Timber Management
Elements of
Forestry
Kenneth Williams
Fisheries Extension Specialist
Langston University Aquaculture
Extension Program
Forest Management

Used to mean biological manipulation of
the forest for timber production.
 Broader meaning now.
Forest Management

Internal variables to forest management
– Temperature
– Rainfall
– Soil type
– Tree species
These variables control production possibilities
Forest Management

External influences
– Federal and state legislation
– Taxation
– Market forces
Forest Management

Balancing the relative productivity of a
forest site with the relative net value of the
product determines which forest
management alternative is selected.
 Analytical techniques are used to choose
management alternatives.
Forest Management

Timber management decisions must
consider impacts on other products desired
from the
forest.
Regulated Forest

A forest that produces a continuous flow of
products of about the same size, quality and
quantity over time is called a regulated
forest.
 What are the advantages of this type of
forest?
Sustained Yield
Flow of timber products over multiple –
year periods must be more or less
continuous.
 Difficult to maintain sustained yield while
transitioning to regulated forest.
 Why? – trees may all be same age. Can not
harvest all of them. Must cut fewer trees
during transition period.

Sustained Yield

The larger the land area the easier a
sustained yield can be managed.
 Large areas offer greater variability in age
classes and more flexibility in timing
harvests.
 Small land owners must use uneven aged
management to achieve sustained yield.
Sustained Yield

Tree crops that make up
sustained yield may come
from the forests of 1
individual or it may be
made up of the combined
forests of many
individuals in a multicounty or state wide area.
Sustained Yield

Practical industrial mill operations require a
continuous daily yield over a wide
geographic area for economic operation.
Even-aged Management

Example: 25 acre forest where trees take 25
yrs. to mature. Then the even-aged
regulated forest would have 25 stands of
equal productivity, each 1 acre in size and
each 1 yr older than the next.
 The 25 yr old stand is harvested each yr and
immediately regenerated.
 Yield is the same each year.
Even-aged Management

Conversion to even – age management from
the example where all trees in the 25 acre
tract were the same age would take 25
years.
Even-aged Management

Problems –
– Must decide the desired age structure of the
forest
– How to manipulate existing forest to obtain it.
– Existing tree species may not be those that are
desired.
Uneven-aged Stands

Trees differ greatly in age, at least 10-20
years difference.
Uneven-aged Stands Harvest
Example

Suppose a stand has sufficient age classes
that some trees were mature every 4 yrs.
 Then the stand could be harvested every 4
yrs.
 Only 4 different stands would be needed to
obtain regulation.
 1 stand cut ea. yr. ea. stand cut every 4 yrs.
 Thus producing regulated forest and
sustained yield.
Rotation Age

Length of time from final harvest cut to
final harvest cut in even-aged management.
 There is no final harvest cut in uneven-aged
management. The stand always exists and is
partially harvested.
 Length of time between cuts in uneven-aged
management is called cutting cycle.
The Normal Forest

Developed in Germany and Austria mid1800’s.
 Based on cutting small, uniform blocks of
even-aged timber.
 3 requirements:
– Normal increment growth
– Normal age class distribution
– Normal growing stock levels
The Normal Forest

Increment growth
considered normal if it
was the maximum
attainable for a
particular species.
 (Increment growth –
increase in all
dimensions of tree
growth or value.)
The Normal Forest

Normal age class distribution consisted of
a series of equally productive stands that
varied in age with oldest age class equal to
rotation age.
The Normal Forest

Normal growing stock is automatically
obtained when increment and age class
distribution are normal.
The Normal Forest

The normal forest does not exist!
 But the conceptual model has influenced
and provides the basis for modern forest
management.
 Ex. Equal annual yields of timber, uniform
age rotation and maximum increment
growth.
Allowable Cut

Amount of timber available for cutting
during a specified time period, usually 1
year.
Allowable Cut

Allowable cut is often not obtained.
– Fluctuations in timber demand
– Weather that prevents access
– Availability of labor
Goal is to achieve allowable cut over a multi-year
period.
Undercutting one year is balanced by over-cutting
in other years.
Even-aged Forest Mgmt. Most
Common

Commercially desirable species grow best
in even-aged stands because they are shade
intolerant.
 Less harvest expense when clearcutting
 Less expense to artificially regenerate a
clearcut stand
 Wildlife habitats are encouraged by creating
forest openings.
Reasons For Uneven-Aged
Management

Small land owners may want as much of a
sustained yield as possible to generate cash
more frequently.
 Other forest products may require
continuous forest cover. Ex – recreation or
aesthetic value.
 Tree species diversity can enhance wildlife
habitat. Both food and shelter.
Choice of even-aged or unevenaged management ?

Depends on land owner objectives.
Even-Aged Management
First – determine rotation age. Trees grow
quickly when young then decrease growth
and finally growth rate levels off.
 At some point volume lost to mortality may
exceed growth.
 Rotation age depends on landowner
objectives.
 Rotation age is chosen that provides
maximum value

Rotation Age

Most common objectives:
– Maximize wood cut or wood flow
– Maximize net cash flow
Rotation Age

Max. wood flow is obtained by maximizing
annual yield. Called Mean Annual
Increment (MAI)
 Total vol. available for harvest in a year
divided by the age of the stand.
Rotation Age

Maximum net cash flow is determined by
economic calculations that take into account
costs, land prices and interest rates. The
results are called land expectation values
(LEV)
 Rotation age is determined by optimizing
the LEV
A forest may never be fully
regulated because:

Changes in ownership
 Additions or subtractions of acreage
 Changes in ownership objectives
 Changes in technology and utilization
Harvest Scheduling
Area control – cutting is controlled by
specifying the number of acres to cut.
 Basically, total acres in forest divided by
rotation age determines how many acres to
cut.
 Oldest stand usually cut first

Harvest Scheduling
Volume control – cutting controlled by
specifying the volume of timber to cut.
 Based on net annual growth of the stand.
 Usually used with uneven-aged
management.

Management Plans

Management objectives and policy
 Forest description
 Economic expectations
 Legal restrictions and public policies
 Silviculture practices, cutting
 Protection from fire, insects and disease
Uneven-Aged Management

Determine desirable level of growing stock
for stand.
 Allow it to grow 5-10 years
 Cut volume of timber equal to growth
 Forest is regulated by manipulating stands
so that an equal volume of timber is cut
each year.
Uneven-Aged Management

Reserve growing stock – that part of the
growing stock left uncut to produce growth
for future cuts.
Uneven-Aged Management

Like living on interest without touching
principal.
Uneven-Aged Management

Difficult and complex decisions required for
optimal use of the management strategy.
– Optimal, sustainable diameter distribution for a
stand. (number of trees in each dia. class.
– Optimal species mix for the stand
– Optimal conversion strategy and conversion
period for ea. stand.
– Optimal treatment scheduling
Harvest Scheduling

Computer models now used for both
management systems. Especially for large,
complex forests
External Influences On Timber
Management

Market for forest products
 Federal and state legislation
 taxation
External Influences On Timber
Management
Markets – decisions based on future
predictions of timber market prices.
 Some silviculture practices based on current
price of materials and labor
 Consumer demand for product drives
pricing of timber and non-timber products
of the forest.

External Influences On Timber
Management

4 types of legislation affect forest
management decisions
– Environmental legislation
– Health and safety legislation (OSHA)
– Federal forest management legislation
– State forestry legislation
External Influences On Timber
Management

Taxation –
– Property taxes
– Income taxes
– Estate taxes
THE END