Estimation of
o glob
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Hatttem, Marc
ch, 2013
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
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Planbureau voor de Leefomgeving
Client
Planbureau voor de Leefomgeving (PBL)
www.pbl.nl
Consultant
Form international
www.forminternational.nl
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Global recovery potential of forest areas
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
SUMMARY
The PBL-Netherlands Environmental Assessment Agency (Planbureau voor de
Leefomgeving) asked Form international to research the potential stock of degraded areas in
key biomes worldwide. This study is based on work done by the World Resource Institute on
the degradation status and carbon content of these same biomes (Leastadius et al., 2012).
From this study area information was used on the states of degradation. WRI identified
Intact, fragmented, degraded and deforested areas and measured the areas covered by
these categories. This information was combined with the total area per biome in each
continent to get information on the diverse states of degradation for each biome per
continent. The data were coupled to growth and yield information for the various forest types
found in the continents. Calculations have been made on the current biomass, carbon, fiber
and timber stock per biome as well as the expected theoretical biomass, carbon, fiber and
timber stock after restoration to maximum biomass of : i) the entire degraded forest area ii)
the entire degraded forest area minus the current agricultural area, and iii) the most
promising area for forest restoration according to the WRI analysis. The time such natural
regeneration will take was estimated based on information available from literature on forest
types in the biomes. As an alternative to natural regeneration, the effects of plantation
management for biomass restoration were estimated.
The study shows that there are great differences in productivity and biomass stocking
between the various biomes. The forests that achieve the highest stocking in terms of
carbon, fiber or timber are the temperate coniferous forests followed by the tropical or
subtropical moist forests. The least productive areas are the boreal forests and the
Mediterranean forests. The forests that are largest in their potential surface area are boreal
forests, tropical and subtropical moist forests and temperate broadleaf and mixed forests.
Some vegetation types with high above ground biomass, such as the tropical rain forests in
the tropical moist broadleaf forest biome, have a surprisingly low per annum productivity in
their original state. Reason for this is intense competition between plants and the great
diversity in tree species. Only few of the total amount of species are relevant commercially
hence greatly reducing harvestable volumes. Simplified systems such as plantations are
sometimes up to 10 times as productive. In some areas, natural vegetation is more
comparable to plantation forests than in other areas, for instance the evergreen forests of the
boreal biome closely resemble a pine forest plantation. In cases like this, differences are
much less pronounced or even absent compared to areas where natural vegetation and
forest plantation cover are very different. Tropical Pines, Eucalyptus and Paraserianthes can
provide very productive plantations.
When making a comparison between strategies for restoration of degraded lands, natural
regeneration without human assistance is cheap but can also be extremely slow. Intensive
plantation management is very quick, but also cost-intensive. A cost effective strategy could
consist of a mix of planting and managed natural regeneration. Where a mosaic of
plantations and deforested lands can create a favorable environment in which stock
restoration takes place at low cost and limited effort.
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
CONTENTS
Summary ................................................................................................................................. 4
Contents .................................................................................................................................. 5
Definitions ............................................................................................................................... 6
1.
Introduction ..................................................................................................................... 9
2.
Study objectives............................................................................................................ 11
3.
Methodology .................................................................................................................. 12
3.1
Overview .................................................................................................................. 12
3.2
Parameters .............................................................................................................. 16
3.3
Forest regeneration time .......................................................................................... 18
3.4
Annual potential harvest loss ................................................................................... 20
3.5
Forest degradation ................................................................................................... 21
4.
Results ........................................................................................................................... 23
4.1
Description of biomes .............................................................................................. 23
4.1.1 Tropical and subtropical dry broadleaf forest ....................................................... 24
4.1.2 Tropical and subtropical moist broadleaf forest .................................................... 25
4.1.3 Temperate broadleaf and mixed forest ................................................................ 26
4.1.4 Temperate coniferous forest ................................................................................ 26
4.1.5 Boreal forest and taiga ......................................................................................... 28
4.1.6 Mediterranean forest, woodland and scrub .......................................................... 28
4.2
Calculations ............................................................................................................. 29
4.2.1 Natural vegetation ................................................................................................ 29
4.2.2 Harvest loss of natural forest................................................................................ 34
4.2.3 Replacing degraded vegetation with plantations .................................................. 36
4.2.4 Comparing regeneration scenarios ...................................................................... 40
5.
Conclusions................................................................................................................... 44
6.
References ..................................................................................................................... 46
Appendix A. Literature Sources of aboveground biomass for natural forest cover...... 51
Appendix B. Literature sources of root/shoot ratio and growth of natural forest ......... 53
Appendix C. Literature sources of Annual Allowable Cut in managed natural forest ... 54
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
DEFINITIONS
Annual Allowable Cut (AAC): Maximum allowable commercial timber volume (m3/ha/y) that
can be extracted from a forest sustainably. It can be considered as the Maximum
Sustainable Yield per year (see also MSY)
Biomass (tons dry weight/ha): the biological material from living, or recently living plants
and trees, expressed as a weight per area. In this report the biomass is expressed as the dry
weight of the plant material, because this is the most common notation and allows for
relevant comparisons to other biomass calculations (see ‘Dry weight’ below). A distinction is
made between aboveground biomass (stem, leaves, branches) and belowground biomass
(roots).
Cutting cycle, rotation, rotation cycle: Term that expresses the duration (yr) of a plantation
from planting to final harvest. The cutting cycle depends on the plantation species, final
product quality, and climatic conditions of a plantation.
Dry weight (DW), or dry matter (DM): The dry matter of plant material is its solids, i.e. all its
constituents excluding water.
Fiber production (tons dry weight/ha) Fiber is calculated as the commercial timber volume
plus 70% of the other above ground biomass (tree top, branches). This percentage is chosen
based on the biomass harvesting guidelines, suggesting that 30% of residue should remain
in the plantation (Evans et al. 2010).
Fiber: Tree material appropriate for panel production. Whole trees can be converted to chips
or ground to fiber for the production of Medium Density Fiberboard and chipboards or be
used as fuel in a biomass electricity plant.
Harvest: Logging of trees for commercial purposes
• Total harvest: Total timber harvested throughout a rotation cycle, including thinnings
• Final felling: Timber harvested at the end of a rotation cycle.
Increment: Growth of the stem diameter.
Managed (natural) forest: Forest growing in managed conditions.
Maximum standing timber volume (m3/ha): Total round-wood volume available for harvest
at end of rotation
Maximum Sustainable Yield (m3/ha/rotation): The MSY is the maximum volume that can
be extracted from a forest or forest plantation per ha, based on the rule that harvests are
never larger than the forest’s increment over a cutting cycle. Increment and harvest levels
are determined in different ways for different forest types and biomes (see also AAC).
Natural forest: Forest naturally occurring in an area.
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Natural forest regeneration time (yr): time to reach recovery up to 100% of maximum
biomass of intact forest. Growth is calculated with a growth rate derived from literature.
Growth lasts until the first moment the maximum biomass for natural forest is reached for that
specific biome.
• Assisted forest regeneration: regeneration under optimal growth values, which can
only be achieved with active forest management (soil preparation, weeding, climber
cutting, fire prevention and protection from encroachment, grazing or browsing ) and
under optimal ecological conditions.
• Unassisted forest regeneration: regeneration without any intervention, simply
allowing the forest to regrow.
Productivity: the annual production capacity of a forest or forest plantation. Expressed in
ton/ha/y or m3/ha/y. Applicable to biomass, timber, fiber and carbon.
• GrowthV (m3/ha/yr): average annual volume increase, or mean annual increment
(MAI) over a rotation cycle, used in this report to express growth of plantation forest.
• GrowthW (tonDW/ha/yr): average annual weight increase of forest, used in this
report to express growth of natural forest.
Pulp: Pulp consists of the cellulose fibers from wood. Wood pulp is the most common raw
material in papermaking.
Regeneration time increase factor: Factor applied to correct for the difference in
regeneration time between managed and unmanaged forest development in the different
degradation states.
Root-shoot ratio: estimated belowground biomass calculated as a fraction of total
aboveground biomass.
Round-wood: Wood in log form. For the purpose of this study round-wood are whole stems
harvested in the forest (so in fact a gross stem volume). Branches and tip have been
removed. Bark is left on the stem. The reason for this is that forest yield tables present
volumes in this way. A translation from gross volume to commercial log volume is rarely
made in available yield tables. From experience with teak however it is clear that, depending
on the diameter, the difference between gross volume over bark and commercial volume
under bark is about -30%.
Stock: weight or volume of biomass, timber, fiber or carbon stored in a forest or forest
plantation. Expressed in ton/ha or m3/ha.
• Typical stock: stock of intact forest that serves as reference per biome
• Current stock: stock of a forest in its current degradation state
• Potentially additional stock: the production gap between current and typical stock
• Potential stock: current stock + potentially additional stock
Timber log (saw log): Log suitable for the conversion into timber. Generally this is the whole
tree minus branches and minus at the tip where it becomes thinner than 10 cm diameter. The
log is usually measured over bark (including bark). During the growth of a plantation two
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
types of logs are produced: i) fiber or firewood logs and ii) saw logs. During the first years it is
fiber or firewood material exclusively. As the girth and height of the trees increase saw logs
start becoming important. At the final felling the firewood / fiber part can be as little as 10% of
tree volume.
Thinning: felling of trees during a cutting cycle to increase productive volume of standing
trees by increasing light availability and decreasing competition.
Total CO2 stock (tons CO2/ha): the amount of above- and belowground carbon stored in
current or potential biomass, calculated by adding the total belowground biomass (total
aboveground biomass multiplied with the root-shoot ratio) to the aboveground biomass, and
multiplied with the carbon fraction.
Total commercial timber volume (m3/ha): total cumulative round-wood produced during
the rotation of the plantation, including thinnings.
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Planbureau voor de Leefo
omgeving
Global recovery potenntial of forest arreas
1. IN
NTRODU
UCTION
N
Forests are produ
uctive ecosy
ystems tha
at offer a variety
v
of products an d services;; timber,
non-timber forest prod
ducts, wate
er purification and carbon sequeestration. In
n recent
fibers, n
years, m
many foressts have be
een convert
rted from productive ecosystems
e
s to areas with
w
low
producttivity.
PBL-Netherllands Env
vironmentall Assessm
ment Agen
ncy (Plannbureau voor de
The P
Leefomgeving PBL
L) recently commission
c
ned the World Resourc
ces Institutee (WRI) to map
m and
orest degra
adation and
d the cons
sequences of this pprocess for carbon
quantifyy global fo
sequesttration, carb
bon stock and wood stock. The
e total amount of landd (in ha) in several
states o
of degradattion was ca
alculated pe
er biome, or
o ‘major ha
abitat type’,, as defined
d by the
World W
Wide Fund for Nature
e (Olsen e
et al., 2001)). This ec
cological claassification system
identifie
es 14 terresstrial biomes
s, further diivided in 86
67 ecoregions. This stuudy focuses
s on 6 of
the 14 b
biomes, with
h forest as their
t
major vegetation type.
RI produced
d a map tha
at shows the
e current sttatus of areas that are potentially suitable
The WR
for foresst vegetatio
on (Laestadiius et al. 20
012) (Figure
e 1).
Figure 1
1. Current sttatus of area
as potentiallyy suitable for forest vege
etation. Darkk green: inta
act forest;
light green: fragmented forest; orange:
o
degra
aded forest; yellow: defo
orested. Sour
urce: Laestad
dius et al.
2012.
One of the findingss of the WR
RI study wa
as that the vast
v
areas of
o degradedd forest rep
present a
huge am
mount of CO
O2 emitted as a resultt of timber extraction
e
and
a other foorms of hum
man use.
Restorin
ng the degraded fores
sts will pote
entially ads
sorb similarrly huge am
mounts of CO
C 2 and
increase
e the produ
uction capacity of woo
od for timbe
er, pulp and firewood. In order to quantify
this, PB
BL has commissioned
d Form intternational to calculatte the poteential stock
k of the
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
degraded forest ecosystems. This report presents an estimation of the current and potential
carbon sequestration, carbon storage and fiber and timber production of forest ecosystems in
different management scenarios; natural regeneration and forest plantation with a selection
of common plantation species. Data on natural regrowth of forest systems in various
ecosystems as well as the potential stock of forest plantations were linked to the numbers
presented by WRI to calculate the global potential stock including the area of the different
stages of degradation per biome.
It is important to notice that this report only regards productivity and stock aspects of forest
restoration. Important other forest values and ecosystem services such as biodiversity, soil
conservation, water purification, scenic and cultural functions are outside the scope of this
report, but do play an important role in the valuation and comparison of good alternatives for
forest restoration.
The report is set up as follows. After a presentation of the study objectives and methodology,
the results are presented. The first results chapter is divided in sections per biome,
presenting a climatic description and an outline of the different forest types that naturally
occur and the most common forest plantation. Subsequently calculation results are
presented for natural forests, plantations and further analyses are presented. Finally,
conclusions and recommendations are made.
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
2. STUDY OBJECTIVES
This study presents the current and potential productivity of forest ecosystems in terms of
biomass, timber, fiber and carbon storage and sequestration, for different management
scenarios.
Calculations will be based on data from WRI about changes in wood and carbon stock at
different levels of degradation.
The results presented in the report will lead to a better understanding of the potential of
degraded areas and can serve as a basis for policy-making on a global scale.
In order to evaluate the potential for restoration, the following information will be presented in
this report:
- Productivity of the original (intact) vegetation for:
o total area of forest biomes
o total area of forest biomes without current agricultural area
o the area which is most promising for restoration according to WRI analysis
- Productivity of the current degraded vegetation (for different levels of degradation)
- Time required for deforested, degraded and fragmented forest to recover to a
productive forest ecosystem (for different levels of degradation)
- Time required for a forest plantation to develop on deforested, degraded and
fragmented land
- Volumes of products (total timber and fiber production, carbon stock and carbon
sequestration) that can be produced by the forest ecosystem or forest plantation.
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
3. METHODOLOGY
3.1 Overview
In order to evaluate the potential for restoration, the following information will be presented in
this report:
- Productivity and stock of the original (intact) vegetation
- Productivity and stock of the current degraded vegetation (for different levels of
degradation)
- Time required for deforested, degraded and fragmented forest to recover to a
productive forest ecosystem with stock and productivity typical for its respective
biome (for different levels of degradation)
- Time required for a forest plantation to develop on deforested, degraded and
fragmented land.
- Volumes of products (total timber and fiber production, carbon stock and carbon
sequestration) that can be produced by the forest ecosystem or forest plantation.
Calculations of the restoration potential are performed per selected biome. We derived the
total area of each of the 6 selected biomes from the biome dataset created by the WRI (table
1).
Table 1. Areas of forest ecosystems in 6 selected biomes, per level of degradation. Total area is
calculated without agricultural land.
Biome
Total
area
(Mha)
Area
intact
(Mha)
Area
fragmented
(Mha)
Area
degraded
(Mha)
Area
deforested
(Mha)
Agricultural
land (Mha)
Boreal
1247
380
663
178
26
5
Mediterranean
152
4
49
25
75
78
Temperate broadleaf
817
20
438
198
161
334
Temperate coniferous
298
42
193
45
18
16
Tropical dry broadleaf
186
7
53
62
64
99
Tropical moist broadleaf
1726
582
592
396
155
216
Global
4426
1035
1988
903
499
748
Source: WRI report, Laestadius et al. 2012
The areas have further been divided into different forest classes based on two parameters:
forest structure and level of degradation. Forests have different structures, with different
percentages canopy cover. In this study they have been reduced to three categorie: closed
forest, open forest and woodland, see table 2 below. In order to use these percentages for
calculations, Form international used the average of the range presented by the WRI.
Table 2. Canopy cover percentage for different forest structures.
Forest structure
Canopy cover according to WRI
Canopy cover assumed in this study
Closed forest
> 45%
70%
Open forest
25% - 45%
35%
Woodland
10% - 25%
17.5%
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Four different levels of degradation were considered in this study: intact forest, fragmented
forest, degraded forest and deforested land, with different percentages of current and
potential biomass cover (table 3 and 4).
Intact forest areas are covered with natural forest that has not or hardly been degraded.
Potential biomass cover percentage and current biomass cover are therefore the same.
Fragmented forest has been degraded in such a way that approximately 30% of the standing
biomass has been removed, but the remaining 70% is still covered with intact forest. Forest
structure therefore remains unchanged but the current biomass cover is 70% of the potential
biomass cover.
Degraded land is land where the structure of the forest has been altered, i.e. closed forest
has been converted to open forest or woodland, or open forest was converted to woodland.
Potential forest cover and current forest cover are therefore different, depending on the
percentage of degraded land per biome and the severity of the degradation.
Deforested land is land where all of the original forest cover has been removed. Current
biomass cover is therefore always 0%, and potential cover varies per biome.
Table 3. Forest class distribution according to the WRI.
Forest class
Potential
Current
1
2
3
4
5
6
7
8
9
10
11
12
Woodlands
Open forests
Closed forests
Woodlands
Open forests
Closed forests
Open forests
Closed forests
Closed forests
Woodlands
Open forests
Closed forests
Status
Woodlands
Open forests
Closed forests
Nonforest
Nonforest
Nonforest
Woodlands
Woodlands
Open forests
Woodlands
Open forests
Closed forests
Intact
Intact
Intact
Deforested
Deforested
Deforested
Degraded
Degraded
Degraded
Fragmented
Fragmented
Fragmented
Table 4. Biomass cover percentage for different levels of degradation.
Variable
Deforested
Degraded
Fragmented
Intact
Canopy cover according to WRI
<10%
25-45%
No value
No value
Biomass cover assumed in this
study*
0%
Calculated per
biome
70%
100%
no cover
randomly
spread
on 100% of
area
70% intact
forest,
30% deforested
complete
cover
Area covered**
* as percentage of total intact forest biomass
** as percentage of area covered with forest biomass
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Part of the land classified as deforested or degraded is used for agricultural purposes. This
land is not considered part of the area available for regeneration. The agricultural areas were
calculated based on the WRI data on global land use.
For each of the 6 selected, forested biomes, data were collected per continent concerning
the biomass stocks, growth rates and regeneration of natural forest vegetation in the
deforested, degraded and fragmented areas, and the growth and stock production of
common plantation types.
For natural forest vegetation, representative values for total biomass (typical stock) were
searched per continent. The typical biomass values (ton DW per hectare) are considered to
be the values of closed forest, i.e. 70% canopy cover. So 100% typical biomass corresponds
to 70% canopy cover. Biomass values for other forest structures (open forest and
woodlands) are derived from this typical biomass value, according to the percentage canopy
cover in table 2. This means that biomass values for open forest are 50% of closed forest
biomass values and woodlands 25% of closed forest biomass values.
In each biome, land cover of closed forest, open forest and woodland is known. Also, the
typical biomass values of each forest structure have been applied to the area per structure
by using a weighing factor (table 5). These calculations resulted in one weighted average
biomass value (combining closed forest, open forest and woodland) per biome.
The relative occurrence of each forest structure (closed forest, open forest, woodland) is
different per degradation level (intact, fragmented, degraded, deforested). Therefore, for
each degradation level the weighted average biomass value is determined separately. This
resulted in weighted average biomass values per biome and per degradation level. This
value shows the potential biomass that these particular areas can reach.
The table below presents an example matrix of the calculations performed to derive the
average biomass values for natural forest in each biome. For each level of degradation, such
a matrix was produced (see table 5 for the matrix of intact forest).
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Table 5. Example matrix for average typical biomass calculation in natural forest, for different
degradation levels (this is the matrix for intact forest). CC = canopy cover.
Biome
Closed
Open
Woodlands
Typical
Weighi
Average
forests area forests area area (ha):
biomass
ng
typical
(ha): 70%
(ha): 35%CC 17.5% CC
closed
factor
biomass
CC
forest
(tDW/ha)
(tDW/ha)
127,125,600
88,168,600
164,865,700
60.1
0.56
33.6
Boreal forest
Mediterranean
12,500
2,424,800
1,469,500
35.5
0.41
14.5
Temperate
broadleaf
Temperate
Coniferous
Tropical Dry
Broadleaf
Tropical Moist
Broadleaf
13,649,400
1,780,800
4,390,200
145.9
0.79
115.1
20,028,900
11,626,600
10,563,800
363.6
0.67
245.3
6,417,300
322,600
86,600
154.9
0.97
149.7
573,853,900
4,278,500
4,046,200
246.8
0.99
244.6
In degraded areas a shift has occurred in forest structure due to degradation (e.g. closed to
open forest). Therefore, for degraded areas, two matrices were produced: one for the current
average biomass and one for the potential average biomass. Potential biomass corresponds
to the biomass cover before degradation (table 6). The difference between potential and
current biomass is potential additional biomass that can be gained through natural forest
restoration. For intact and fragmented forest a single matrix was produced, because the
forest structures have not changed due to degradation. For fragmented forest it was
assumed that 30% of the land is deforested while 70% remains intact. For deforested areas
0% forest is left. Thus, the matrix for deforested areas represents the potential biomass that
can be attained in these areas.
Table 6. Calculation of potential additional biomass in degraded forest per biome.
Biome
Potential average
Current
Potential
biomass (tDW/ha) average
additional
biomass
biomass
(tDW/ha)
(tDW/ha)
52.9
37.2
15.6
Boreal forest
Potential
growth (%)
30%
Mediterranean
32.4
22.0
10.4
32%
Temperate broadleaf
141.4
99.8
41.7
29%
Temperate Coniferous
355.2
281.6
73.6
21%
Tropical Dry Broadleaf
135.7
112.8
22.9
17%
Tropical Moist Broadleaf
245.5
196.4
49.1
20%
For forest plantations, three common plantation tree sprecies were selected per biome for
each continent. This selection was further narrowed down to a selection of three
representative plantation types per biome. This selection was based on plantation
characteristics and suitability for the biome, using the following criteria:
- Availability of information
- Variation in products and product quality
- Suitability for the major habitat types within the biome
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Global recovery potential of forest areas
Frequency of occurrence within the biome
High potential productivity within the biome
Typical biomass per plantation type was derived from literature, as well as other parameters,
described in the following section (Paragraph 3.2: Parameters).
3.2 Parameters
The following parameters and assumptions were used to calculate the desired output, as
described above:
- Total aboveground biomass at adult (climax) stage
- Growth rates of natural forest ecosystems and forest plantations
- Biomass Conversion Expansion Factor (BCEF)
- Root/shoot ratio
- Carbon fraction (0.47)
- Thinning factor
- Regeneration time increase factor
A detailed description of these parameters is presented below.
Total aboveground biomass of intact closed forest per biome per continent was derived
from various sources in literature, but a major part originates from Roy et al. (2001). In case
multiple data points were found for a biome on a single continent, an aggregate variable was
calculated. For plantations, total aboveground biomass at the end of the rotation cycle was
calculated as a derivative from the total harvest, using a Biomass Conversion Expansion
Factor (as explained below) and a factor for the amount of timber generated by thinnings
(thinning factor). The total harvest was found in several sources of literature, e.g. Cubbage et
al. (2010) and FAO (2001).
GrowthW (tonDW/ha/year) of natural forest were derived from the IPCC values on aboveground biomass and biomass growth per ecological zone (IPCC 2006) and from data
presented in Roy et al (2001). GrowthV (m3/ha/yr) of different plantation types was derived
from various literature sources. Both for natural forests and plantations growth rates are
expressed as a mean annual increment over a specific time frame. This provides a linear
figure for calculation purposes, but the underlying growth curve is a logistic curve, as this is
the natural forest growth pattern. In Figure 2 this pattern is illustrated for the boreal biome,
but the pattern is applicable to each of the biomes. The presented values for natural forests
are valid for the regeneration period, plantation values are valid for their respective rotation
periods.
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Example growth curve of boreal forest
Above‐ground biomass (tonDW/ha)
60
y = 2,3064x ‐ 0,1532
50
40
30
Boreal forest
20
10
0
0
5
10
15
20
25
30
Regeneration time (years)
Figure 2. Example growth curve of boreal forest demonstrating linear and logistic forest growth
curves.
The Biomass Conversion and Expansion Factor (BCEF) for expansion of merchantable
stock volume (in m3/ha) to above-ground biomass (in ton/ha) was derived from the IPPC
guidelines (2006). This BCEF was applied to convert plantation volumes for stock and
productivity to biomass. It is important to note that this conversion has two components:
conversion of volume to weight and expansion from commercial stem part to the total above
ground biomass. The conversion from volume to weight is made through a species specific
wood density, which can range from 80-1100 kg/m3. Also the ratio between commercial stem
volume and total above-ground biomass is species specific. Therefore species specific BCEF
values are applied.
The ratio of below-ground biomass to above-ground biomass, or root-shoot ratio (R), was
determined based on the values in the IPCC guidelines (2006). These are values adopted
from Mokany et al. (2006).
The carbon fraction of aboveground forest biomass was standardized at 0.47 ton C per ton
DW as recommended by the IPCC guidelines, McGroddy et al. (2004) (see IPCC 2006)
(2006).
For forest plantations, a thinning factor was developed to determine the fraction of wood
extracted from thinnings compared to the final felling at the end of the rotation cycle. This
factor was based on a comparison of yields of final felling volumes and thinning volumes in
several yield tables for different rotation cycles (table 7). This factor is necessary to apply,
since in most cases literature cites the total timber production per rotation cycle, pooling
thinning and total harvest volumes together.
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Table 7. Biomass from final felling expressed as a percentage of the total harvest after a full rotation
(including thinnings).
Rotation cycle (yr)
Percentage final felling of total harvest
0-20
80%
20-30
60%
30+
45%
Regeneration time increase factor: see next section.
3.3 Forest regeneration time
For the degraded forest state, the time (in years) for recovery up to the full biomass stocks is
calculated taking the biomass stock percentages given table 4 as starting point. It is
assumed that full stock potential is reached when the biomass level reaches the level of
intact forest (typical stock = 100% biomass). The equation used for regeneration time for
natural forest is as follows:
Natural forest regeneration time = (Biomasspotential – Biomasscurrent) / growth rate
Based on the definitions given in table 4, it is assumed that forest develops from 0% biomass
in the deforested situation, since no forest is left. In the degraded situation, the current and
potential biomass cover differ per biome, so the potential additional biomass is calculated per
biome based on the shift in forest structure (see table 6 for potential and current values). In
fragmented areas it is assumed that 70% of the area is covered with intact forest and on 30%
of the area no forest is left. Therefore, the forest development is calculated for 30% of the
area, starting from 0% biomass.
To further complete our model for estimating regeneration times for natural forests we will
have a closer look at the dynamics of forest restoration.
The development time of forest ecosystems starting from various initial situations typically
depends on the initial land use situation, in which biotic (flora and fauna) and abiotic (soil,
hydrology, climate) determine the speed and direction of spontaneous forest recovery. As an
example of forest restoration dynamics we can regard an example of tropical forests. The
general picture of tropical forest recovery through secondary succession after pasture or
agricultural use (shifting cultivation) is that forest structural characteristics such as tree
density, canopy height, basal area and biomass accumulation develop fast and can reach a
situation similar to old growth forest in about 30 to 50 years (Finegan, 1996; Brearley et al.,
2004; Chazdon, 2003; Van Gemerden et al, 2003). Species richness develops in a slower
pace and floristic composition remains different for a long time, due to limited seed dispersal
capacity of many primary forest species.
The rate of forest structural and compositional recovery is accelerated when the extent and
intensity of forest degradation prior to reforestation is limited, soils are fertile and if remnant
forest is nearby (Chazdon, 2003, Guariguata and Ostertag, 2001). Forest recovery is much
more difficult or slower when these factors are adverse. This will be of great influence on the
biodiversity aspects as well. Estimates for unassisted natural regeneration have been made
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showing that it may take more than 150, 200 or even 500 years to arrive at primary forest
composition (Finegan, 1996; Chazdon, 2003), but with low intensity, smaller-scale
disturbances in a forested landscape with sufficient seed dispersal this may already be
achieved in 50-60 years (Van Gemerden et al, 2003).
Based on literature we determined forest development times for managed natural forests.
These values were mainly based on IPCC and Roy et al. (2001). These values must be seen
as optimal growth values, which can only be achieved with active forest management and
under optimal ecological conditions. In the early growing stages of deforested and heavily
degraded ecosystems this generally includes soil preparation, weeding, climber cutting, fire
prevention and protection from encroachment, grazing or browsing. After canopy closure
management must focus on regular thinning to keep optimal growth. Without thinning growth
slows down due to competition and higher natural mortality rates.
In cases where degradation negatively impacted biotic and abiotic success factors such as
soil quality (e.g. fertility, physical properties, depth), seed dispersal (seed banks, distance to
seed sources, species pool, seed dispersing animals) and microclimate, the optimal growth
rate must be reduced to account for these regeneration barriers.
Figure 3. Degraded vegetation on the site of former dry semi-deciduous forest in Ghana.
In order to correct for the difference in regeneration time between managed and unmanaged
forest development and the different degradation states, we developed a Regeneration time
increase factor per degradation state and per biome that differentiates between optimal
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forest development times in managed regenerating forests and increased development times
under unmanaged conditions (see table 8 below). It was assumed that the regeneration time,
calculated with the growth rates for natural forest as found in IPCC (2006) and Roy et al.
(2001), would apply to growth under managed conditions for all degradation levels. This
assumes that management is more intensive in more degraded states in order to achieve
optimal growth rates (Figure 3). For example in fragmented forest, conditions are still good
and only exclusion of degradation factors (encroachment, fire, grazing etc.) is needed,
whereas in degraded and deforested areas also, soil preparation, weeding and probably
(enrichment) planting or seeding needs to be carried out. For unmanaged conditions, the
increase factors below apply (table 8). The factors for tropical forests are based on the
literature review described earlier in this section where in optimal conditions tropical forest
can be restored in 30-50 years, whereas in adverse conditions this may take 3 times longer.
Another assumption with these factors is that the causes of degradation are removed. If
degradation continues, the regeneration time is negative or slowed down significantly.
Table 8. Increase factors for regeneration time of managed forest compared to unmanaged forest, per
degradation level, per biome, as applied for calculations in table 7.
Biome
Deforested
Degraded
Fragmented
Boreal
1.5
1.25
1.12
Mediterranean
1.5
1.25
1.12
Temperate broadleaf
1.5
1.25
1.12
Temperate coniferous
1.5
1.25
1.12
Tropical dry broadleaf
3
2
1.5
Tropical moist broadleaf
3
2
1.5
Plantation development time: The time it takes for plantations to develop from a clearfelled area to maximum stock capacity is given as the rotation time, which is available in
literature and presented in this study.
3.4 Annual potential harvest loss
To provide an insight into the annual potential harvest loss from non-intact forests an
overview is created of the lost annual harvest potential in deforested, degraded and
fragmented forests compared to the situation in which they would all still be intact and fully
productive as sustainably managed natural forests. Sustainable management of natural
forests is based on the principles of harvesting according to maximum sustainable yields
(MSY). The MSY is based on the rule that harvests are never larger than the forest’s
increment over a cutting cycle. Increment and harvest levels are determined in different ways
for different forest types and biomes. To make sense in a practical way they need to take into
account the silvicultural system that is applied (e.g. selective, clear felling, monocyclic,
polycyclic) and the harvesting objective (timber, fiber, fuel wood, non-timber products). In
practice forests are managed with a variety of management objectives, targeted products
and species. However, to make comparison between biomes and forests possible a scenario
was chosen that all forests are managed to produce commercial timber. The annual
allowable cut (AAC) is an accepted forestry measure to express the maximum sustainable
harvest level and is therefore applied to make comparison between biomes possible. A
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representative figure was determined based on literature for the annual allowable cut (AAC)
per biome for forests managed to produce commercial timber (roundwood). The AAC per
biome is a weighted composite value based on representative values per continent.
For the tropical moist forest biome a selective logging system was chosen, which is the most
widely applied silvicultural system there. Also, for tropical dry forests a selective logging
system was chosen, but we do need to remark that they are generally not managed for
commercial timber production, but rather for livestock ranching and charcoal making. For all
other biomes a system based on intermediate thinning and clear felling was chosen. In
practice this system is widely applied in all biomes outside the tropics, and differences in
scale and technical characteristics of silvicultural systems across these biomes are largely
included in this basic management model.
In the tropics only part of the available tree species is commercially used. This has to be
accounted for in calculating the AAC. The AAC value is therefore much lower than the
annual increment for the complete forest ecosystem. Outside the tropics the vast majority of
available species have commercial value. However, in practice not the full annual increment
is harvested due to practical, market and societal constraints to harvesting. In Europe,
harvest rates are typically 65% of annual wood increment. This factor was taken into account
to determine potential harvest loss.
The potential harvest loss is 100% of the AAC in deforested and degraded areas, because
the ecosystems are below their threshold level for sustainable harvesting. In fragmented
forests potential harvest loss is 30% of AAC, because there is still 70% of well-functioning
forest.
3.5 Forest degradation
Forest degradation is frequently caused by overexploitation of natural forest. Large trees are
removed at a faster rate than the time required for them to regenerate, changing forest
composition and impoverishing the standing stock. This process commonly takes place
unintentionally and is only noticed when degradation is in a stadium in which it is difficult and
time-consuming to reverse. In order to keep up with the desired productivity, logging
standards are dropped and the forest degrades even further. Over time the vegetation cover
converts to fast growing species and grasses. This will lead to an increased fire hazard and
provides opportunities for agricultural land use. Regular burning causes a decrease in soil
quality: nitrogen mineralization increases temporarily, resulting in a short term increase in
nutrient availabiliy. On the long term however, burning destroys living material in the soil,
which leads to reduced moisture retention capacity and increased soil density. It removes the
organic material that would add humus and nitrogen and causes increased soil erodibility.
Organic matter content decreases, as well as total nitrogen, total sulfur, carbon/nitrogen
ratios, extractable carbon, polysaccharide, ammonium, and available phosphorus. Apart from
the soil, burning also affects the microclimate. All of these factors make unassisted natural
forest regeneration difficult. In reverse, tree/vegetation cover can improve impoverished soils
in a number of ways:
‐ organic matter addition
‐ enhanced mineral weathering
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‐
‐
‐
‐
Global recovery potential of forest areas
nutrient pumping and recycling
symbiotic N-fixation
interception of particles and dusts from the air
improved soil structure through root action
Addition of organic matter is the most important factor contributing to soil quality; this
improves physical, chemical and biological soil properties. According to Bongers &
Tennigkeit (2010), soil organic matter “improves soil structure, decreases soil bulk density,
binds soil particles together to form stable aggregates that are resistant to erosion, allow
water infiltration and thereby reduce runoff, improves water-holding capacity, prevents the
effect of soil dispersion by raindrops and reduces surface crusting and hard setting”. Indirect
effects that benefit the soil include changes in microclimatic conditions and decreasing soil
erosion.
Because of the capacity of trees to improve soil quality and build topsoil, assisted forest
regeneration can take place even on very shallow soils (e.g. lithic leptosols, commonly less
than 10cm deep), although trees will not reach their maximum capacity on these soils, at
least during the first years/decades of plantation establishment. In this report we assume that
the area where forest regeneration cannot take place due to insufficient soil thickness is
negligible and therefore this factor is not taken into account.
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Global recovery potenntial of forest arreas
4. R
RESULTS
S
4.1 D
Descriptio
on of biomes
The WW
WF divides the world’s terrestrial ssurface into
o 8 terrestrial ecozoness, or realms
s, based
on the distribution
nal pattern
ns of terresstrial organ
nisms; Afro
otropic, N
Neotropic, Nearctic,
N
Palearcctic, Antarcttic, Indoma
alaya, Austtralasia and Oceania. In each ecozone, different
regions can be reccognized ac
ccording to
o their clima
atic and geo
ological chaaracteristics
s, taking
sification
into acccount the evolutionary history of tthe planet. The WWF has termeed this class
ed as a "la
‘biomess’, or ‘major habitat ty
ypes’, define
arge units of land or water conttaining a
geograp
phically disstinct assem
mblage of species, natural
n
com
mmunities, and enviro
onmental
conditio
ons". The global biome
es are the re
esults of regional analy
yses of bioddiversity ac
cross the
continen
nts and oceans of the
e world, co
ompleted in
n collaboration with huundreds of regional
experts worldwide and by co
onducting exxtensive lite
erature reviews. The 14 major te
errestrial
habitat types desscribe diffe
erent areass of the world
w
that share sim
milar enviro
onmental
ons, habitatt structure and
a
pattern
ns of biolog
gical comple
exity, and tthat contain
n similar
conditio
communities
an
nd
specie
es
adapta
ations
(O
Olson
et
al.,
2 001,
see
e
also
orldwildlife.o
org/biomes) (Figure 4) .
www.wo
Figure 4
4. “Terrestria
al Biomes” ha
ave been divvided in 14 biiomes and 8 bio-geograpphical areas (Olsen et
al. 2001)).
This stu
udy deals with
w 6 of the 14 terrestri al biomes, selected ba
ased on theeir large fore
est cover
and pottential carbo
on content:
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-
Global recovery potential of forest areas
Tropical and subtropical dry broadleaf forests
Tropical and subtropical moist broadleaf forests
Temperate broadleaf and mixed forests
Temperate coniferous forests
Boreal forests and taiga
Mediterranean forests, woodlands, and scrub
In the following paragraphs, each of the selected biomes is introduced, describing the range,
climatic conditions and major forest types. The descriptions are largely based on the
information presented on the website of the WWF (Source: www.worldwildlife.org/biomes).
4.1.1
Tropical and subtropical dry broadleaf forest
Range: southern Mexico, southeastern Africa, the Lesser Sundas, central India, Indochina,
Madagascar, New Caledonia, eastern Bolivia and central Brazil, the Caribbean, valleys of the
northern Andes, and along the coasts of Ecuador and Peru. The most biologically diverse dry
forests in the world occur in southern Mexico and in the Bolivian lowlands.
Climate: warm year-round, up to several hundred centimeters or rain per year, with long dry
seasons lasting several months. Dry season duration and time of occurrence vary with
geographic location. The seasonal droughts have great impact on all forest life.
Potential natural vegetation: deciduous trees predominate. In order to conserve water during
the dry season, many tree species have a leafless period (e.g. Tectona grandis, Adansonia
spp., Delonix regia). During the leafless period sunlight can penetrate the canopy and allows
the growth of thick underbrush.
Selected plantation types: • Eucalyptus camaldulensis (Red river gum)
• Shorea robusta (Sal)
• Tectona grandis (Teak)
Fauna: a wide variety of wildlife including monkeys, large cats, parrots, various rodents, and
ground dwelling birds.
Degradation risks: highly sensitive to excessive burning and deforestation (Figure 5);
overgrazing and exotic species can also quickly alter natural communities. Fauna are
threatened by hunting, wildlife trade, and land conversion. Restoration is possible but
challenging, particularly if degradation has been intense and persistent.
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Global recovery potential of forest areas
Figure 5. Fire is a serious risk to dry tropical forests.
4.1.2
Tropical and subtropical moist broadleaf forest
Range: large, discontinuous patches centered on the equatorial belt, particularly in the IndoMalayan Archipelagos, the Amazon Basin, and the African Congo.
Climate: low variability in annual temperature, high levels of rainfall (>200 centimeter
annually). The warm, wet climate promotes explosive vegetation growth.
Tropical and subtropical moist forests are dominated by semi-evergreen and evergreen
deciduous tree species. Species diversity is higher than any other terrestrial biome. Half of
the world's species can be found in these forests and a square kilometer can harbor over
1,000 tree species. In general, biodiversity is highest in the forest canopy which can be
divided into five layers: overstory canopy with emergent crowns, a medium layer of canopy,
lower canopy, shrub level, and finally understory.
Selected plantation types:
• Tectona grandis (Teak)
• Paraserianthes falcataria
• Eucalyptus grandis (Giant gum)
Fauna: The canopy is home to apes and monkeys. Below the canopy, a lower understory
hosts snakes and big cats. The forest floor, relatively clear of undergrowth due to the thick
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Global recovery potential of forest areas
canopy above, is prowled by other animals such as gorillas, antelopes and deer. Emergent
trees are the realm of hornbills, toucans, and the harpy eagle. High diversity of invertebrate
species, including New Guinea’s unique stick insects and bird wing butterflies that can grow
over one foot in length.
Degradation risks: clearing for pasture and crops, large-scale commercial logging of tropical
hardwoods as well as natural catastrophes (hurricanes) threatens some moist forests. Due to
challenging climatic and soil conditions the forests are highly sensitive to disturbance like
plowing, overgrazing and excessive burning.
4.1.3
Temperate broadleaf and mixed forest
Range: central China and eastern North America, Caucasus, Himalayas, southern Europe,
and the Russian Far East. Examples of forest regions are the Himalayan broadleaf forests,
Appalachian-Blue Ridge forests, East Central Texas forests, Mississippi lowland forests.
Climate: wide range of variability in temperature and precipitation, with on average 60-150
cm of rainfall per year. In regions where rainfall is evenly distributed throughout the year,
deciduous trees mix with evergreen species.
Potential natural vegetation: characteristic tree species are oak (Quercus spp.), beech
(Fagus spp.), birch (Betupa spp.) and maple (Acer spp.). In contrast to tropical rain forests,
most biodiversity is concentrated close to the forest floor.
Selected plantation types:
• Cryptomeria japonica (Japanese cedar)
• Quercus robur (Pedunculate oak)
• Populus deltoides (Poplar)
Fauna: bobcats, bears, cougars and wolves are examples of species occurring in temperate
forests of North and South America. Australian forests house endemics like koalas, possums
and wallabies. Animals like the Giant panda and red panda are found in temperate
rainforests of Asia. Other than the animals mentioned above, the list of forest animals found
in this region also includes several species of reptiles, birds, insects, microorganisms and
primates.
Degradation risks: many forests are impacted by fire, and few old-growth forest groves
remain because of human use. Exotic species can have extensive and significant impacts on
native communities; the loss of large native predators has many cascading impacts on forest
structure and ecology. However, restoration potential for these forests is relatively high.
4.1.4
Temperate coniferous forest
Range: Forest communities dominated by huge trees (e.g., giant sequoia, Sequoiadendron
gigantea; redwood, Sequoia sempervirens; mountain ash, Eucalyptus regnans, occur in
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Global recovery potential of forest areas
western North America, southwestern South America, as well as in the Australasian region in
such areas as southeastern Australia and northern New Zealand. Temperate rain forests
only occur in 7 regions around the world - the Pacific Northwest, the Validivian forests of
southwestern South America, the rain forests of New Zealand and Tasmania, the
Northeastern Atlantic (small, isolated pockets in Ireland, Scotland, and Iceland),
southwestern Japan, and those of the eastern Black Sea and in the coastal areas of
Washington state, USA.
Climate: warm summers and cool winters. Mainly coastal areas of regions that have mild
winters and heavy rainfall, or inland in drier climates or montane areas.
Potential natural vegetation: great variety in plant life. Either dominated by needle leaf trees
or home primarily to broadleaf evergreen trees or a mix of both tree types. Tree species
include pine, cedar, fir and redwood. The understory commonly contains a wide variety of
herbaceous and shrub species. Temperate conifer forests sustain the highest levels of
biomass in any terrestrial ecosystem and are notable for trees of massive proportions in
temperate rainforest regions.
Selected vegetation types:
• Cryptomeria japonica (Japanese cedar)
• Abies grandis (Grand fir)
• Thuja plicata (Western red cedar)
Fauna: badgers, boars and wolves inhabit the temperate coniferous forests of Europe. Owls,
stoats and birds of prey are commonly found throughout this biome.
Figure 6. Larch forest in temperate coniferous biome.
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Global recovery potential of forest areas
Degradation risks: logging and fragmentation of natural forests. Late-successional species
typically regenerate slowly. Exotic species can have extensive and significant impacts on
natural forest communities.
4.1.5
Boreal forest and taiga
Range: extensive tracts of boreal forest and taiga still exist in the northern Nearctic and
Palearctic, the largest expanses being in central and eastern Russia.
Climate: low annual temperatures, precipitation ranges from 40-100 cm/yr, mainly snow.
Nutrient poor soils as a result of permafrost and the resultant poor drainage.
Potential natural vegetation: low levels and variation of species richness and endemism.
Dominated by conifer species (Abies, Picea, Larix, and Pinus) and species of deciduous
trees (Betula spp., Populus spp.). Ground cover is dominated by mosses and lichens.
Selected plantation types:
• Larix gmelinii (Eastern larch)
• Picea abies (Norway spruce)
• Pinus banksiana (Jack pine)
Fauna: large-scale migrations of caribou, reindeer (Rangifer tarandus) and intact predator
assemblages can still be found in some regions, as well as relatively unaltered natural
disturbance regimes.
Degradation risks: acid rain and other forms of pollutants. Regeneration of mature forests
takes a long time due to the challenging climate and soil conditions.
4.1.6
Mediterranean forest, woodland and scrub
Range: the Mediterranean, south-central and southwestern Australia, the fynbos of southern
Africa, the Chilean matorral, and the Mediterranean biomes of California.
Climate: hot and dry summers, cool and moist winters in which most of the precipitation
occurs.
Potential natural vegetation: broadleaf trees, e.g. oak and mixed sclerophyll forests
(California and the Mediterranean), Eucalyptus (Southwest Australia), Nothofagus (central
Chile), pine and oak (California) and coniferous forests (Mediterranean). Forests are often
found in riparian areas because of the (summer) water supply.
Most plants are fire adapted and dependent on this disturbance for their persistence.
Selected plantation types:
• Eucalyptus grandis (Giant gum)
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•
•
Global recovery potential of forest areas
Pinus halepensis (Aleppo pine)
Pinus radiata pulpwood (Radiata pine)
Fauna: characteristic species for the European and African Mediterranean forests are the
Iberian lynx, Barbary macaque and the Barbary stag. Many of the fauna species in the
Mediterranean woodlands and forests have disappeared as a result of human disturbance,
which has affected especially the large predators like the Egyptian wolf, Atlas bear, Barbary
lion and the Barbary leopard. In the Chilean matorral, several species of lizards, including
various South American swifts of the genus Liolaemus can be found. Other animals include
five endemic rodents, a species of mouse opossum, and 15 endemic birds, including three
species of tapaculo birds, the Chilean mockingbird, the Chilean Tinamou, and the Giant
hummingbird.
Degradation risks: habitat fragmentation, grazing, and alteration of fire regimes (over burning
or fire suppression), native species are particularly at risk from exotic plants and animals that
establish and spread with ease in these communities. Restoration of communities is feasible
but fire regimes must be restored and exotics controlled effectively.
4.2 Calculations
4.2.1
Natural vegetation
To provide insight in the potential productivity of degraded vegetation, information was
collected concerning the productivity of natural vegetation in the biomes, as well as
information on the potential for natural regeneration. The information was collected per
biome per continent and then summarized so as to present information per biome. In table 1
the area per biome is presented. These areas have been obtained from the Ecoregion
dataset elaborated by WRI and provided by PBL.
Each biome has a specific species composition and therefore its own productivity. Between
the continents, the biomes differ in productivity as well. In the table below key productivity
parameters for intact vegetation are presented per biome (see appendix A for numbers per
continent and sources). The numbers are composed of averages for each continent,
weighted by area (table 9). These numbers represent the biomass values for closed forest,
hence at 70% canopy cover, and were used as a basis for calculating the typical productivity
values per biome, based on the fraction of closed forest in each biome. For each level of
degradation a matrix was produced to calculate these values per biome.
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Table 9. Typical stock per hectare of intact natural forest ecosystems (70% canopy cover) per biome
Biome
Typical aboveTypical total
Typical
Typical
Typical total
ground
biomass
standing
fiber
carbon
3
(tC/ha)
biomass
(tDW/ha)
timber (m /ha) (tDW/ha)
(tDW/ha)
60
82
38
53
38
Boreal
36
53
22
31
25
Mediterranean
146
181
81
126
85
Temperate
broadleaf
364
436
214
319
205
Temperate
coniferous
155
198
96
137
93
Tropical dry
broadleaf
247
338
127
211
159
Tropical moist
broadleaf
Figure 7. Potential biomass of intact closedl forest in selected biomes in tonDW/ha.
The growth information can be converted to present the current values for the biomes in
above ground biomass, standing timber, total carbon and fiber (Figure 7) (see appendix B for
the used root/shoot ratio and annual growth, and sources). The rules for calculating these
values are as follows:
- intact forest area is included completely, - fragmented forest area is included for 70% - degraded forest area is included completely, using the current biomass cover
percentage - 30 -
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Global recovery potential of forest areas
deforested area is not included at all since biomass stocks are 0%. In table 10, the total stock of each biome was calculated, taking into account the various
levels of degradation in each biome.
Table 10. Current stock of forest ecosystems per biome
Biome
Current above
ground biomass
(MtDW/biome)
Current total
biomass
(MtDW/biome)
Current
standing
timber
(Mm3/biome)
Current
fiber
(MtDW/bio
me)
Current
Carbon
(MtC/
biome)
Boreal
37,541
51,055
23,648
33,373
23,996
Mediterran
ean
1,178
1,766
734
1,044
830
Temperate
broadleaf
60,777
75,363
33,765
52,673
35,421
Temperate
coniferous
61,193
73,432
35,996
53,634
34,513
Tropical
dry
broadleaf
12,025
15,391
7,492
10,665
7,234
Tropical
moist
broadleaf
317,384
434,816
162,761
270,997
204,363
Global
490,096
651,824
264,395
422,386
306,357
The degraded vegetation presents a potential to regenerate and provide commodities again
during its restoration. For each biome, information has been collected on the recovery time
from a given state of degradation to fully productive vegetation (in terms of total biomass).
Total biomass was used as a criterion because through forest management activities the
composition of products may change over time, but the biomass will stay more or less
constant from a certain moment onwards. Over time, biomass becomes distributed over
fewer, but bigger and more valuable trees. In this way, the forest starts to produce fiber and
is gradually able to produce more quality timber. Carbon stocks evolve as a more or less
constant fraction of forest biomass.
The time it takes for forest vegetation to recover depends greatly on whether or not the area
is managed. This is presented in the table below (table 11). Please note that it is assumed
that forest develops from 0% biomass in the deforested situation. In degraded areas, the
current and potential biomass cover differ per biome, so the potential additional biomass is
calculated per biome. In fragmented areas it is assumed that 70% of the area is covered with
intact forest and on 30% of the area no forest is left. Therefore, the forest development is
calculated for 30% of the area, starting from 0% biomass (see also table 4).
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Table 11. Productivity (typical growth), and regeneration time (in years) of natural forest for different
levels of degradation in managed and unmanaged conditions, per biome.
Fragmented forest
Degraded forest
Deforested
reg. time
managed
(yr)
reg. time
unmanag
ed (yr)
reg. time
managed
(yr)
reg. time
unmanag
ed (yr)
reg. time
managed
(yr)
Biome
Typical
GrowthW
(tDW/ha/
yr)
reg. time
unmanag
ed (yr)
Boreal
2.3
19
17
9
7
33
22
Mediterra
nean
1.5
13
11
9
7
18
12
Temperat
e
broadleaf
4.0
36
32
13
11
50
33
Temperat
e
coniferou
s
10.2
31
28
9
7
48
32
Tropical
dry
broadleaf
4.4
36
24
10
5
68
23
Tropical
moist
broadleaf
7.9
44
29
12
6
84
28
In the figure below, the typical GrowthW of natural forest per biome is presented (Figure 8).
Figure 8. Typical growth of timber under natural forest regeneration per biome, in tDW/ha/yr
- 32 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
The vegetation in the biomes can regenerate to a certain additional stock. In addition to the
current stocking values presented in Table 10. Table 12 shows the potential stock values that
can be reached after complete regeneration (stock over the rotation cycle = stock over x
years), excluding the area designated for agricultural purposes.
Table 12. Potential additional stock of natural forest ecosystems per biome, excluding agricultural
land.
Biome
Potential
Potential
Potential
Potential
Potential
additonal
additonal
additonal
additional
additonal
above ground total
standing
fibre
carbon
biomass
biomass
timber
(MtDW/
(MtC/
(MtDW/
(MtDW/
(Mm3/
biome)
biome)
biome)
biome)
biome)
18,481
25,135
11,642
16,430
11,813
Boreal
Mediterranean
2,399
3,599
1,495
2,128
1,692
Temperate broadleaf
65,897
81,713
36,610
57,111
38,405
Temperate coniferous
38,190
45,829
22,465
33,473
21,539
Tropical dry broadleaf
16,571
21,211
10,324
14,697
9,969
Tropical moist
broadleaf
Global
173,460
237,641
88,954
148,108
111,691
315,000
415,127
171,490
271,947
195,110
Table 13 below shows the potential total stock of natural forest ecosystems. This is the sum
of the current natural forest stock (table 10) and the potential additional stock (table 12).
Table 13. Total potential stock of natural forest ecosystems per biome, excluding agricultural land.
Biome
Potential
above ground
biomass
(MtDW/
biome)
Potential
total
biomass
(MtDW/
biome)
Potential
standing
timber
(Mm3/
biome)
Potential
fibre
(MtDW/
biome)
Potential
carbon
(MtC/
biome)
Boreal
56,022
76,190
35,290
49,802
35,809
Mediterranean
3,577
5,366
2,229
3,173
2,522
Temperate broadleaf
126,674
157,076
70,374
109,784
73,826
Temperate coniferous
99,383
119,260
58,461
87,107
56,052
Tropical dry broadleaf
28,595
36,602
17,816
25,362
17,203
Tropical moist
broadleaf
490,844
672,457
251,715
419,105
316,055
Global
805,096
1,066,950
435,885
694,333
501,467
- 33 -
Planbureau voor de Leefomgeving
4.2.2
Global recovery potential of forest areas
Harvest loss of natural forest
Table 14 below shows that Annual Allowable Cut (AAC) per biome is lowest for tropical
biomes. This is mainly due to the small percentage of harvestable species, but also to slow
growth in mature natural forest. As a rule of thumb, the AAC in non-tropical biomes is
approximately 65% of the annual (commercial and non-commercial) growth of natural forests
presented in table 18 (converted to volumes). Table 14 shows that the global total potential
harvest losses due to deforestation and degradation are large. The annual potential harvest
loss is largest in the temperate broadleaf biome, followed by temperate coniferous and
boreal biomes. The AAC and annual harvest loss are presented as volumes (m3) as they
apply to commercial timber volumes that are harvested. An expression in volumes (m3) is
consistent with forestry practices and literature. The timber volumes can be transformed to
weight and to other variables (carbon, fibre, biomass) by applying the conversion factors
explained in the methodology chapter.
Table 14. Annual Allowable Cut and annual harvest loss of deforested, degraded and fragmented
forest ecosystems and agricultural land compared to potential annual harvest per biome.
Biome
AAC
Annual potential harvest loss (Mm3/yr)
3
(m /ha/yr)
Fragmented Degraded
Deforest
Agricultu Total
ed
re
2.5
506
452
66
12
Boreal
1,036
Mediterranean
1.6
23
40
120
126
310
Temperate broadleaf
3.2
421
635
518
1,071
2,646
Temperate coniferous
9.5
549
424
170
156
1,299
Tropical dry broadleaf
0.2
4
14
14
22
53
Tropical moist
broadleaf
Subtotals
0.9
165
368
144
201
878
1,669
1,933
1,032
1,587
6,222
In the figure below, the typical growthV in m3/ha/yr of timber of the original forest cover is
presented per biome (Figure 9).
- 34 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Figure 9. Typical productivity of natural forest vegetation per biome in m3/ha/yr.
The data presented can be compared to those presented in the chapter on plantations below
to evaluate the differences between natural regeneration and regeneration through planting.
It should be noted that natural regeneration is calculated to the level of maximum biomass
stocking, whereas plantations are often managed for certain products. Long rotation
plantations might reach their maximum biomass stocking well before the end of the rotation
cycle. This goes for regenerating natural forests as well.
- 35 -
Planbureau voor de Leefo
omgeving
4.2.3
Global recovery potenntial of forest arreas
Repla
acing deg
graded ve
egetation with plan
ntations
Figure 1
10. Vegetatio
on repeatedly
y logged with
hout the requ
uired time forr regrowth beecomes degrraded.
A method for accelerating re
ecovery of land to a productive state is thhe establish
hment of
plantatio
may take long to de
ons. Where
e natural vegetation
v
evelop to a productiv
ve state,
plantatio
ons can ach
hieve this in
n a short pe
eriod of time
e. To estimate the prodductivity pe
er biome,
yield tab
bles of vario
ous common plantation
n species have been consulted (seee referenc
ces).
Per biom
me speciess have been
n selected tthat are fre
equently pla
anted and w
whose silvic
culture is
well und
derstood (ta
able 15).
- 36 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Table 15. Selected plantation tree species per biome and their main products. Pu: Pulp (thinning), Po:
Poles (thinning), St: Sawn timber (thinning + final harvest).
Biome
Species
Common name
Product types
Boreal
Larix gmelinii
Eastern larch
St
Picea abies
Norway spruce
Pu, St
Pinus banksiana
Jack pine
Pu, St
Eucalyptus grandis
Giant gum
Pu, St
Pinus halepensis
Aleppo pine
Pu, St
Pinus radiata
Radiata pine
Pu
Cryptomeria japonica
Japanese cedar
Pu, St
Quercus robur
Pedunculate oak
Pu, St
Populus deltoides
Poplar
Pu
Cryptomeria japonica
Japanese cedar
Pu, St
Abies grandis
Grand fir
Pu, St
Thuja plicata
Western red cedar
Pu, St
Eucalyptus camaldulensis
Red river gum
Pu
Shorea robusta
Sal
Pu, St
Tectona grandis
Teak
Po, St
Tectona grandis
Teak
Po, St
Paraserianthes falcataria
Albizia
Pu, St
Eucalyptus grandis
Giant gum
Pu, St
Mediterranean
Temperate broadleaf
Temperate coniferous
Tropical dry broadleaf
Tropical moist broadleaf
Of these species, information on growth was collected from articles and yield tables. Yield
tables often provide the best insight in the growth of a species in plantations. Unfortunately
yield tables cannot always be found for suitable species or only very summarized information
is available. To be able to make meaningful calculations information about rotation length
and growth is needed. In the table below basic information on the selected species is
presented (table 16).
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Table 16. Basic parameters of selected plantation types per biome.
Biome
Plantation type
Rotati Growt Abovegr
Total
on
hV
ound
biomass
3
age
(m /ha biomass
(tDW/
(yr)
/yr)
(tDW/
ha)
ha)
190
0.4
27.4
37.2
Boreal
Larix gmelinii
Mediterranea
n
Temperate
broadleaf
Temperate
coniferous
Tropical dry
broadleaf
Tropical
moist
broadleaf
Global min max
Final
Harvest
(m3/ha)
Total
fiber
(tDW/
ha)
47
39
Picea abies
74
6.2
109
149
206
139
Pinus banksiana
100
4.1
92
125
184
119
Eucalyptus
grandis
Pinus
halepensis
Pinus radiata
pulpwood
Cryptomeria
japonica
Quercus robur
29
16.0
184
276
278
212
120
3.9
114
171.5
161
110
16
20.0
141
211
256
175
80
7.8
196
243
280
222
120
6.5
282
350
352
303
Populus
deltoides
Cryptomeria
japonica
Abies grandis
8
14.0
72
89
90
77
80
7.8
196
236
280
222
150
7.9
375
451
536
424
Thuja plicata
80
24.2
610
733
872
689
Eucalyptus
camaldulensis
Shorea robusta
10
12.0
63
81
96
73
50
9.5
141
181
214
163
Tectona grandis
30
8.6
102
131
155
118
Tectona grandis
20
17.0
258
354
272
262
Paraserianthes
falcataria
Eucalyptus
grandis
8
50.0
304
416
320
309
16
15.0
182
250
192
185
639 1631
838 2,104
866 2,243
707 1,814
In the figure below, the GrowthV of forest plantations is presented for the selected plantation
types, per biome (Figure 11).
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Figure 11. GrowthV (MAI) of forest plantations for selected tree species per biome, in m3/ha/yr.
To be able to conclude what the potential is for these biomes the areas they represent have
to be multiplied with the values per hectare.
Using the area per biome and the productivity data per species, a list of potential plantation
forest stock per biome is calculated. The areas included in this calculation are the areas that
are currently without forest cover: 100% of deforested land, 100% of degraded land
(assuming that the current, degraded vegetation is removed before replanting with the
plantation species), 30% of fragmented land (assuming that the 70% of intact forest remains
untouched). Stock numbers were calculated with each selected plantation tree species
applied to the whole biome. This allows for a comparison per biome between stocks in
natural regeneration or assisted natural regeneration and plantation development (table 17).
Please note that the timber stock presented in this table illustrates the total amount of timber
produced in the rotation cycle, including the thinnings.
- 39 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Table 17. Potential stock of selected plantation types for each biome.
Biome
Plantation type
Total timber
(Mm3/biome)
Total fiber
(Mt/biome)
Total carbon
(MtC/biome)
Boreal
Larix gmelinii
31,811
12,010
7,046
Picea abies
184,653
55,756
28,150
Pinus banksiana
164,208
48,031
23,616
Eucalyptus grandis
53,012
24,237
14,800
Pinus halepensis
52,783
16,270
9,210
Pinus radiata
pulpwood
36,560
20,035
11,341
Cryptomeria japonica
305,808
108,715
56,141
Quercus robur
384,149
148,666
80,598
Populus deltoides
54,949
37,805
20,495
Cryptomeria japonica
75,233
26,745
13,366
Abies grandis
143,870
51,146
25,560
Thuja plicata
233,910
83,155
41,556
Eucalyptus
camaldulensis
17,074
10,409
5,424
Shorea robusta
67,586
23,175
12,076
Tectona grandis
36,753
16,803
8,756
Tectona grandis
247,765
191,274
121,247
Paraserianthes
falcataria
291,488
225,029
142,644
Eucalyptus grandis
174,893
135,017
85,586
390,520 1,214,798
238,256 - 560,018
141,127 319,824
Mediterranea
n
Temperate
broadleaf
Temperate
coniferous
Tropical dry
broadleaf
Tropical
moist
broadleaf
Global min max
4.2.4
Comparing regeneration scenarios
In order to compare growth in natural and plantation forests, GrowthW (in tonDW/ha/yr), was
converted to GrowthV (in m3/ha/yr), using the Biomass Conversion and Expansion Factor
(BCEF), see paragraph 3.2. Comparing the results from the study on natural regeneration of
degraded vegetation, in managed and unmanaged conditions to plantation forestry shows
that results can often be obtained quicker and with more certainty when the option of planting
is chosen (table 18). The GrowthV of forest in the natural regeneration option is divided into
commercial and non-commercial growth. Commercial growth is equal to Annual Allowable
Cut (AAC), indicating the growth that is harvested in practice. This number can be compared
to the growth of plantation forest, as both numbers represent commercialized volumes. Noncommercial growth in the natural regeneration option is calculated as total growth of timber
minus the AAC. This number represents the growth volume of timber that is not harvested in
practice.
- 40 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Table 18. GrowthV for plantations and GrowthW of natural forest, per biome.
Biome
Plantation option
Natural regeneration option
Plantation type
GrowthV
(m3/ha/yr)
GrowthV noncommercial
(m3/ha/yr)
GrowthV
commercial
(m3/ha/yr)
Boreal
Pinus banksiana
4.1
1.4
2.5
Mediterranean
Eucalyptus grandis
16.0
0.9
1.6
Temperate broadleaf
Cryptomeria japonica
7.8
1.7
3.2
Temperate coniferous
Thuja plicata
24.2
5.1
9.5
Tropical dry broadleaf
Eucalyptus
camaldulensis
12.0
7.1
0.2
Tropical moist broadleaf
Tectona grandis
17.0
7.5
0.9
In the table below, we present the potential total timber stock for the plantation option and the
natural forest regeneration, including the time required to reach the maximum timber stock
(table 19). The rotation age and regeneration time indicate the time required to reach the
indicated stock levels for the plantation scenario and the natural forest scenario respectively.
The bottom row presents the global sum of the potential timber stock, achieved in a full
plantation coverage and full natural forest scenario.
Table 19. Potential total timber stock and rotation time/regeneration time of plantation and
regenerated natural forest per biome.
Plantation option
Natural regeneration option
Biome
Rotatio
n age
Total timber
(Mm3/biome)
Regeneration
time managed
(yr)
Regeneration
time
unmanaged
(yr)
Total timber
(Mm3/biome)
Boreal
100
73,893
22
33
11,642
Mediterranean
29
31,807
12
18
1,495
Temperate
broadleaf
80
137,614
33
50
36,610
Temperate
coniferous
80
105,260
32
48
22,465
Tropical dry
broadleaf
10
13,660
23
68
10,324
Tropical moist
broadleaf
20
198,212
28
84
88,954
Global
560,445
171,490
The areas most promising for forest restoration were calculated per biome (table 20). These
areas fall in the deforested and degraded areas as presented in table 1.
- 41 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Table 20. Area of most promising land for reforestation, per degradation level, per biome.
Biome
Deforested land (ha)
Degraded land (ha)
Boreal Forest
3,298,800
42,372,300
Mediterranean
4,663,500
5,981,800
Temperate broadleaf
24,597,800
70,602,400
Temperate Coniferous
4,836,900
24,113,300
Tropical Dry Broadleaf
4,861,600
21,669,900
Tropical Moist Broadleaf
31,783,300
152,408,200
Total
74,041,900
317,147,900
The potential stock that can stand on the most promising areas for forest restoration was
calculated for both the natural regeneration and the plantation forest scenario (table 21 and
22).For the plantation option, it was assumed that the most promising areas on degraded
land were cleared before planting.
Table 21. Potential plantation stock on most promising areas for forest restoration, per biome.
Biome
Plantation
type
Potential
aboveground
biomass (MtDW)
Potential
total
biomass
(MtDW)
Potential
timber
(Mm3)
Potential
fiber
(MtDW)
Potential
carbon
(MtC)
Boreal
Pinus
banksiana
4,193
5,702
8,385
5,450
2,680
Mediterra
nean
Eucalyptus
grandis
1,956
2,934
2,964
2,964
2,258
Temperat
e
broadleaf
18,692
23,178
26,703
26,703
21,095
Cryptomeria
japonica
Temperat
e
coniferou
s
Thuja
plicata
17,673
21,208
25,247
25,247
19,946
Tropical
dry
broadleaf
Eucalyptus
camaldulens
is
1,681
2,152
2,547
2,547
1,941
Tropical
moist
broadleaf
Tectona
grandis
47,595
65,205
50,100
50,100
48,347
91,790
120,379
115,947
113,012
96,267
Total
- 42 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
Table 22. Potential natural forest stock on most promising areas for forest restoration, per biome.
Biome
Potential
aboveground
biomass (MtDW)
Potential total
biomass
(MtDW)
Potential
timber
(Mm3)
Potential
fiber
(MtDW)
Potential
carbon
(MtC)
Boreal
2,407
3,273
1,516
2,140
1,538
Mediterranean
278
417
173
247
196
Temperate broadleaf
13,231
16,407
7,351
11,467
7,711
Temperate coniferous
10,158
12,190
5,976
8,904
5,729
Tropical dry broadleaf
3,427
4,387
2,135
3,040
2,062
Tropical moist
broadleaf
44,502
60,968
22,822
37,998
28,655
Total
74,004
97,642
39,973
63,795
45,892
- 43 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
5. CONCLUSIONS
In order to provide insight into the extent to which forest and related functions may be
potentially restored, data on current forest status and on growth potential is useful. Though
exact information on the extent of lands available for forest restoration, reforestation or land
reclamation is not currently available, rough estimates can be made with existing data sets.
When comparing the information from the World Resource Institute (Laestadius et al. 2012)
with information on biomes form the World Wildlife Fund (Olson et al., 2001) the 6 biomes we
studied cover 4,426 million hectares (44 million km2) of which 1,035 million hectares (10
million km2) are currently intact forests (total terrestrial area without ice cover is about 130
million km2). Approximately 1,988 million hectares of forest is fragmented and 903 million ha
is degraded. Of the potential range of forest within the biomes studied, 499 million hectares
are deforested. Another 748 million hectares of deforested and degraded land is classified as
agricultural land. The total area that has the potential for forest restoration is approximately
1998 Mha, 491Mha of which is classified as most promising for reforestation.
The various biomes differ in stock and productivity due to climatic and soil conditions, but
also due to the species composition of the vegetation. The forests in the Mediterranean
zones and in the boreal zones have a low annual productivity whereas the temperate
coniferous forests and the temperate moist broadleaf and mixed forests have a high natural
stock and productivity when managed responsibly. The stock and (economic) productivity of
tropical and subtropical moist forests is surprisingly low. The reason for this is that of the total
tree biomass only a few species are currently of commercial interest.
The regeneration time for degraded forest vegetation to recover to a vegetation with
maximum biomass is quite variable between the biomes. This rate is low for boreal forests
and Mediterranean forests and quite high for tropical and subtropical moist forest and
temperate coniferous forests. The time it will take in Boreal forests to go from deforested to
forest with maximum above ground biomass is 33 years when no assistance is provided and
22 years when assistance is provided. For tropical and subtropical moist forest these
recovery times are 84 and 28 years respectively. The difference between unmanaged boreal
and tropical can be explained by the much higher pressure of degrading impacts on tropical
lands and the rapid loss of ecosystem integrity following forest loss. Once vegetation has
been cleared it will often stay that way due to shifting cultivation, fire and grazing activities.
Also, degradation leads to persistent disturbance vegetations, degraded soils and loss of
biotic recovery potential such as seed dispersal capacity.
When comparing the recovery rate of natural vegetation with the rate at which plantations
can accumulate biomass and be productive, the difference between boreal and (sub)tropical
moist forest is caused by different aspects. Plantation forests in the boreal forest areas are
very similar to natural forests in that area, regarding tree species and forest composition. To
a lesser extent this is true for temperate broadleaf and mixed forest and temperate
coniferous forest as well. The growth of plantations and forests regenerating spontaneously
will be rather similar for this reason. Plantations in (sub)tropical moist forests are usually very
different from the original vegetation. High yielding exotic species are mostly used to create
- 44 -
Planbureau voor de Leefomgeving
Global recovery potential of forest areas
plantations. In terms of the harvestable volume per hectare per year the difference can be as
much as tenfold.
When deciding a strategy on how to deal with degraded forests or degraded lands, choices
have to be made on resources that can be allocated to restoration activities. From the study
it becomes clear that plantations can be a means to quickly install a productive vegetation in
a given area. Depending on the condition of the soil, the climate and biotic and abiotic risks,
this can be an expensive activity. Unfortunately areas where the adverse factors decrease
growth potential of tree plantations, thereby increasing production costs, are also areas
where spontaneous regeneration, suffering from these same factors, is extremely difficult.
The possibilities have to be studied on a case by case basis. One of the feasible options is to
design a strategy so that the areas with highest risk for further degradation and the areas
with best possibility for high production are planted with priority. This would avoid the risk of
losing the best terrains and may halt the degradation beyond recovery of the others.
Combined strategies of assisted natural regeneration and plantation development can also
be explored, especially in areas where mosaics of different degradation states and other land
uses are found. Internal analyses performed by Form international indicated in 2010 that
natural forest restoration combined with forest plantation development can be very costeffective.
A great body of scientific information exists on the productivity of natural vegetation in the
various biomes. Currently only few publications exist that bundle the stock and productivity of
natural vegetation from all biomes. For the productivity of plantations such bundling does not
exist. Much of the information on the productivity of plantations is still only found in grey
literature and currently little research is done on this subject. It would be good that more
information on plantation species becomes available so the choice whether or not to invest in
plantations becomes easier and based on research and quantitative data. We believe that
detailed species information may also increase diversity in plantation activities.
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
6. REFERENCES
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Global recovery potential of forest areas
APPENDIX A. LITERATURE SOURCES OF ABOVEGROUND BIOMASS FOR NATURAL
FOREST COVER
Biome
Continent
Abovegound biomass
Source
Boreal
Asia
56
Shivdenko & Nilsson 1994 (p243)
Europe
101
Stanners & Bourdeau 1995 (p244)
North America
47
Kurz & Apps 1993 (p241)
Total
60
Africa
523
Rambal in Roy et al (2001)
Asia
111
Rambal in Roy et al (2001)
Australia
470
Rambal in Roy et al (2001)
Europe
258
Rambal in Roy et al (2001)
North America
249
Rambal in Roy et al (2001)
South America
61
Rambal in Roy et al (2001)
Total
36
Australia
360
IPCC (2006)
Asia
125
IPCC (2006)
Europe
120
IPCC (2006)
North America
162
Whittaker 1974
South America
155
IPCC (2006)
Total
146
Africa
120
IPCC (2006)
Asia
125
IPCC (2006)
Europe
120
IPCC (2006)
North America
550
Tsui (2012)
Mediterranean
Temperate broadleaf
Temperate coniferous
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Tropical dry broadleaf
Tropical moist broadleaf
Global recovery potential of forest areas
Total
364
Africa
130
IPCC (2006)
Asia
145
IPCC (2006)
North America
210
IPCC (2006)
South America
167,6
IPCC (2006), Klinge & Herrera (1983), Jordan & Uhl (1978), Saldarriaga
(1985)
Total
155
Africa
285
IPCC (2006)
Asia
262
IPCC (2006)
Australia
220
IPCC (2006)
South America
221
IPCC (2006), Klinge (1976), Fölster et al. (1976)
Total
247
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SEIA Afrenso Brohuma
FORM Ghana
APPENDIX B. LITERATURE SOURCES OF ROOT/SHOOT
RATIO AND GROWTH OF NATURAL FOREST
Biome
Root/shoot
ratio
Source
GrowthW
(tonDW/ha/yr)
Source
Boreal
0.36
Gower
2.3
Roy et al (2001)
Mediterranean
0.5
Roy et al. (2001)
1.5
Mooney (1981), Specht
(1969a)
Temperate
broadleaf
0.24
Monkany (2006)
(in IPCC 2006)
3.95
IPCC (2006) weighted
average by surface area of
continents
Temperate
coniferous
0.2
Monkany (2006)
(in IPCC 2006)
10.2
IPCC (2006) weighted
average by surface area of
continents
Tropical dry
0.28
Monkany (2006)
(in IPCC 2006)
4.4
IPCC (2006)
Tropical moist
0.37
Fittkau & Klinge
(1973) (in IPCC
2006)
7.9
IPCC (2006)
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Planbureau voor de Leefomgeving
Global recovery potential of forest areas
APPENDIX C. LITERATURE SOURCES OF ANNUAL
ALLOWABLE CUT IN MANAGED NATURAL FOREST
Biome
BCEF
GrowthV
(m3/ha/yr)
Yield
factor
AAC
(m3/ha/yr)
Source
Boreal
GrowthW
(tonDW/ha/
yr)
2.3
0.59
3.9
0.65
2.54
Roy et al (2001)
Mediterranean
1.5
0.61
2.5
0.65
1.61
Temperate
broadleaf
3.95
0.8
4.9
0.65
3.21
Temperate
coniferous
10.2
0.7
14.6
0.65
9.47
Tropical dry
broadleaf
Tropical moist
broadleaf
4.4
0.61
7.3
0.22
7.9
0.95
8.4
0.93
Mooney (1981), Specht
(1969a)
IPCC (2006) weighted
average by surface area
of continents
IPCC (2006) weighted
average by surface area
of continents
Dauber et al. (2005),
FAO 2002
Lamprecht (1989), De
Graaf (1986), Sist et al.
(1998), Sist & Fereira
(2007), Pinard et al.
(2000), Bertault & Sist
(1997), Sist et al.
(2003), Medjibe & Putz
(2012), Holmes et al.
(2002), Vanclay (1993),
Form valuations (2011),
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