Technical Journal of Engineering and Applied Sciences
Available online at www.tjeas.com
©2013 TJEAS Journal-2013-3-22/3098-3101
ISSN 2051-0853 ©2013 TJEAS
A comparative study on wood density and pH of Oak,
Maple and Iron trees in the North of Iran
Maryam Babai Khalkhali
Department of chemistry, Khalkhal Branch, Islamic Azad University, Khalkhal, Iran
Corresponding author: Maryam Babai Khalkhali
ABSTRACT: Wood density and pH has been frequently studied as an indicator of wood quality. In this
research wood density and pH of Oak, Maple and Iron trees were studied in the Guilan forest area in the
North of Iran. The mean of wood density of Oak, Maple and Iron wood was determined 0.75, 0.61 and
-3
0.82 gr.cm . The mean of pH value of Oak, Maple and Iron wood trees were determined 4.3, 4.2 and 4.4.
The ANOVA test showed that the tree species had significantly effect on wood density but not had
significantly effect on pH value. The results showed that the Maple tree had the heist radial growth and
the Iron wood had lowest radial growth in the study area.
Keyword: Wood characteristics, wood density, radial growth, Hyrcanian forest
INTRODUCTION
Wood is a natural renewable material. Wood is an extremely versatile material with which to work. Physical
properties are the quantitative characteristics of wood and its behavior to external influences other than applied
forces. Indeed according to Cown et al., (1992) much of the variation in wood strength, both between and within
species, can be attributed to differences in wood density. Donaldson et al. (1995) also expressed the opinion that
density is one of the most important properties influencing the use of a timber. Wood density has been frequently
studied as an indicator of wood quality (Evans and Ilic, 2001). Wood density and wood specific gravity both indicate
the amount of actual wood substance present in a unit volume of wood (Zobel and Jett, 1995). The wood density is
a measure of the cell wall material per unit volume and as such gives a very good indication of the strength
properties and expected pulp yields of timber. Variations in wood density originate from differences in wood
anatomical characteristics, such as the proportion, size and distribution of woody tissues (Kramer and Kozlowski,
1979; Zobel and van Buijtenen, 1989), which occur amongst others due to variations in environmental factors.
Wood quality can be defined in terms of attributes that make it valuable for a given end use (Jozsa and Middleton,
1994). Wood density is related to a number of plant functional traits and is an important indicator of the mechanical
properties of woods (Panshin and de Zeeuw, 1980; Chave et al., 2009). The pH value of wood or woody materials
is an important criterion of its suitability for various applications (Kalnins and Feist, 1993; Good, 1992). The real
temperate commercial deciduous forests, with an area of almost 2 million ha, are extended in the north of Iran, in
the Caspian Region, the so called Hyrcanian forest (Rouhi-Moghaddam et al., 2008). These are the most valuable
forests in Iran. The marketable species include beech (Fagus orientalis) and hornbeam (Carpinus betulus), maple
(Acer insigne), oak (Quercus castanefolia), alder (Alnus subcordata), elm (Ulmus glabra), ash (Fraxinus excelsior),
and Iron wood (Parrotia persica). Wood quality can be defined in terms of attributes that make it valuable for a
given end use (Jozsa and Middleton, 1994). The aim of this study was to determine density and pH of Oak, Maple
and Iron trees in the Caspian forest, north of Iran.
MATERIAL AND METHODS
In this research 10 normal trees from each tree species (Quercus castanefolia, Acer insigne and Parrotia
persica) were selected in Shafarood forest area in the Guilan province, North of Iran. Disks and logs from each
selected tree were cut at breast height. The age of trees was 75 to 80 years old. The annual rainfall and annual
average temperature was 1241 mm and 11.2°C, respectively. The altitude of this site was 240 m. The soil type is
forest brown and soil texture varies between sandy clay loams to clay loam. From each tree, a cross-sectional of
Tech J Engin & App Sci., 3 (22): 3098-3101, 2013
approximately 5 cm in thickness was taken at diameter at breast height (DBH) levels. These discs were used for
the determination of density and pH values. The wood density was determined by ASTM-D143 standard method.
The pH value was determined by TAPPI T509 OM-96 Standard method.
RESULTS AND DISCUSSION
The trees and site characteristics are shown in table1. The diameter at breast height (dbh) of Oak, Maple
and Iron wood was 75.6, 64.3 and 45.5 cm (Table1). The density of trees in Oak, Maple and Iron wood were 244,
279 and 260 trees per hectare.
Table1. Characteristics of sampled trees and sites
Tree Species
Tree
characteristic
s*
Oak
(Quercus castaniefolia)
Maple
(Acer velutinum)
Iron wood
(Parrotia persica)
Site
characteristic
s**
DBH (cm)
Height (m)
Age (year)
Density (st.h1
)
Slope (%)
Soil texture
75.6
19.7
71
244
37
SL
64.3
18.9
53
279
35
LS
45.5
14.3
63
260
36
SL
*: DBH: Diameter at breast height, **: SL: Sandy loam, LS: Loam sandy
-3
The mean of wood density of Oak, Maple and Iron wood was determined 0.75, 0.61 and 0.82 gr.cm
(Fig.1). The Iron wood had the heist wood density and the Maple tree had lowest wood density. The mean of wood
density of Iron wood had significantly differences (α=0.05) with means of wood density of maple and oak trees and
the mean of wood density of maple tree had significantly differences (α=0.05) with wood density of Oak tree from
Duncan test (Fig.1). Cown (1992) reported that the density of wood is recognized as the key factor influencing
wood strength. Density is one of the most important wood characteristics that wood strength and stiffness, pulp
yield, and caloric content are all closely correlated with wood density (Haygreen and Bowyer, 1996).
Figure 1. Mean and Standard error of wood density in tree species
Panshin and de Zeeuw (1980) reported that density is a general indicator of cell size and is a good
predictor of strength, stiffness, ease of drying, machining, hardness and various paper making properties.
Research has shown that higher density species tend to have stronger timber than lower density species (Walker
3099
Tech J Engin & App Sci., 3 (22): 3098-3101, 2013
and Butterfield, 1996). The wood density affected by the cell wall thickness, the cell diameter, the earlywood to
latewood ratio and the chemical content of the wood (Cave and Walker, 1994). Each tree species has its own
characteristic wood density. Density variation between species is basically due to differences in anatomical
structure. The maximum wood density was demonstrated to provide additional information on climate−growth
relationships for a variety of tree species (Hughes et al., 1984; Schweingruber et al., 1993).
The mean of pH value of Oak, Maple and Iron wood trees were determined 4.3, 4.2 and 4.4 (Fig.2). These
means were not significant differences at α=0.05 from Duncan test. The pH is closely related to glue bond quality
and total manufacturing cost, and must be considered as one of the important factors in determining the suitability
of the raw material. Maloney (1993) explained that the effect of acidity on cure rate or press times is due to the
combination of pH, buffer capacity and the existing or potential total free volatile acid content of the material.
Figure 2. Mean and standard error of wood pH in tree species
-1
The results showed that the Maple tree had the heist radial growth (6.1 mm.year ) and the Iron wood had
-1
-1
lowest radial growth (3.6 mm.year ) in the study area (Fig3). The radial growth of Oak wood was 5.3 mm.year .
Figure3. Mean of radial growth in tree species
The ANOVA test showed that the tree species had significantly effect on wood density but not had
significantly effect on pH value (Table2).
Table2. Analysis of variance (ANOVA) for effect of tree species on value of wood density and pH
Density
pH
SS
0.233
0.245
Df
2
2
Ms
0.117
0.123
F
493.11
0.224
P-value
0.000**
0.801NS
**: Significant at α=0.01, NS: No Significant
CONCLUSION
Wood density and wood pH value of Oak (Quercus castaniefolia), Maple (Acer velutinum) and Iron wood
(Parrotia persica) were studied in the Hyrcanian forest in the north of Iran. The wood density of these tree species
was significantly differences, but pH value was not significantly differences. Wood density can vary among
provenances and is very variable among trees and within individual trees of a given provenance (Zobel and Van
Buijtenen, 1989). Wood density is influenced by the environment, which determines the rate of tree growth.
3100
Tech J Engin & App Sci., 3 (22): 3098-3101, 2013
REFERENCES
Cave ID, Walker JCF. 1994. Stiffness of wood in fast-grown plantation softwoods: the influence of microfibril angle. Forest Products Journal
44(5):43-48.
Chave J, Coomes D, Jansen S, Lewis SL, Swenson NG, Zanne AE. 2009. Towards a worldwide wood economics spectrum. Ecology Letters 12:
351–366.
Cown DJ, Young GD, Burdon RD. 1992. Variation in wood characteristics of 20 year old half - sib families of Pinus radiata. New Zealand Journal
of Forest Science 22(1): 63-76.
Cown DJ. 1992. Corewood - should we be concerned? New Zealand Journal of Forest Science 22(1): 87-95.
Donaldson LA, Evans R, Cown DJ, Lausberg MJF. 1995. Clonal variation of wood density variables in Pinus radiata. New Zealand Journal of
Forest Science 25(2): 175-188.
Evans R, Ilic J. 2001. Rapid prediction of wood stiffness from microfibril angle and density. Forest Products Journal 51(3): 53-57.
Good RJ. 1992. Contact angle, wetting, and adhesion: A critical review. J. Adhesion Sci. Technol. 6(12):1269-1302.
Haygreen JG, Bowyer JL. 1996. Forest Products and Wood Science (An introduction). 3rd ed. - Ames: Iowa State University Press, 490 pp.
Hughes MK, Schweingruber FH, Cartwright D, Kelly PM. 1984. July–August temperature at Edinburgh between1721 and1975from tree-ring
density and width data. Nature 308:341-344.
Jozsa LA, Middleton GR. 1994. A discussion of wood quality attributes and their practical implications. Forintek, Canada Special Publication No.
SP - 34.
Kalnins MA, Feist WC. 1993. Increase in wettability of wood with weathering, Forest Products Journal 43(2): 55-57.
Kramer PJ, Kozlowski TT. 1979. Physiology of woody plants. Academic Press, New York, 811 p.
Maloney TM. 1993. Modern particleboard and dry-process fiberboard manufacturing (updated edition), Miller Freeman, San Francisco.
Panshin AJ, De Zeeuw C. 1980. Textbook of wood technology. New York, NY: McGraw-Hill Publishing Co.
Rouhi-Moghaddam E, Hosseini SM, Ebrahimi E, Tabari M, Rahmani A. 2008. Comparison of growth, nutrition and soil properties of pure stands
of Quercus castaneifolia and mixed with Zelkova carpinifolia in the Hyrcanian forests of Iran. Forest Ecology and Management 255:
1149–1160.
Schweingruber FH, Briffa KR, Nogler P. 1993. Atree-ring densitometric transect from Alaska toLabrador. International Journal of Biometeorology
37:151-169.
Walker JCF, Butterfield BG. 1996. The importance of the microfibril angle for the processing industries. New Zealand Journal of Forestry 40(4):
34-40.
Zobel BJ, Jett JB. 1995. Genetics of wood production. Springer-Verlag, Berlin, 337 pp.
Zobel BJ, Van Buijtenen JP. 1989. Wood variation: Its causes and control. Springer-Verlag, New York. 363p.
3101