VARIABILITY in WOOD PROPERTIES of SIX-YEAR-OLD PLANTED MERANTI TREES (Shorea Leprosula, S

IAWA Journal, Vol. 18 (4), 1997: 405-413

VARIABILITY IN WOOD PROPERTIES OF SIX-YEAR-OLD PLANTED MERANTI TREES (Shorea leprosula, S. parvifolia and S. pauciflora, Dipterocarpaceae) by Monique T. M. Bosman

Rijksherbarium / Hortus Botanicus, P. O. Box 9514, 2300 RA Leiden, The Netherlands

SUMMARY

Radial and longitudinal variation in fibre wall percentage, area percen tage of vessels and resin canals and specific gravity was studied in five superior six-year-old plantation grown trees of red meranti (Shorea leprosula, S. parvifolia and S. paucijlora). In another 23 trees of these species specific gravity was measured at breast height. Variation within the trees appeared small and did not show consistent patterns for any of the three parameters. The variance between trees of a species, however, is significantly larger than the variance within the trees and that among the species. For all three parameters, the values found in the six-year-old trees correspond closely to those found in previously studied full-grown trees, which suggests that these superior six-year-old trees will not produce wood significantly better or worse than is the case for the full grown trees. Specific gravity in the planted trees is not significantly correlated to the two recorded growth rate parameters, height and diameter. The limited data on rnicro-environmental conditions at the time of planting, however, show that light and humidity may influence specific gravity, at least in the first years of growth. The suggestion that trees from cuttings perforrn somewhat better than transplanted wildlings because they show relatively high values for specific gravity, can only be confirrned when the influence of micro-environmental conditions and the diameter increment of these trees is known. Key words: Shorea leprosula, Shorea parvifolia, Shorea paucijlora, juvenile wood, tropical hardwoods, fibre wall percentage, specific gravity, tissue proportions, plantations, cuttings, wildlings.

INTRODUCTION

To relieve the pressure on the natural tropical forests of Southeast Asia, various efforts are being undertaken to grow commercially important hardwoods, especially species of the Dipterocarpaceae, on large-scale plantations and in enrichment plantings. The

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Table 1. Trees studied: arranged by species and ascending order of specific gravity. Trees marked with an asterisk (*) have been studied for within-tree variation. Micro-environmental data at the time of planting (light intensity, soil, vegetation type) from data set of Dr. W. Smits (no extra information available). -lep = Shorea leprosula; par =S. parvifolia; pau = S. pauciflora; wild!. = transplanted wildling; cutt. = propagated from cutting; seed!. = seedling; prim. f. = primary forest; sec. f. = secondary forest; fullgr. = fullgrown.

Tree species origin light soil vegeta- height diam. s.g. number tion (inm)

1.276* lep wild!. dark swamp prim. f. 6.3 5.4 0.17 22.35 lep wild!. light slope shrub 6.0 7.5 0.22 s3.20 lep cutt. 8.3 0.24 28.43 lep wild!. light slope shrub 10.0 6.8 0.24 20.35* lep wild!. light down hill shrub 7.3 7 0.24 22.48 lep wild!. light slope shrub 8.0 7 0.27 s9.1 lep cutt. 6.5 0.27 p2 lep seed!. 9.0 0.28 s11.1 lep cutt. 9.1 0.30 s2.13 lep cutt. 9.0 0.31 24.27 lep wild!. light down hill shrub 7.0 6 0.31 s4.14 lep cutt. 9.1 0.32 1.277* par wild!. dark swamp prim. f. 7.0 6.1 0.20 22.36 par wild!. light slope shrub 9.0 7.1 0.23 25.39 par wild!. light down hill shrub 7.1 5.2 0.26 26.44 par wild!. light slope shrub 7.0 6.1 0.27 s4.16 par cutt. 9.5 0.30 slO.19 par cutt. 4.5 0.30 s2.29 par cutt. 7.2 0.34 36.54 pau wild!. light swamp young 8.0 7.2 0.27 sec. f. 20.47 pau wild!. light slope shrub 9.0 7.4 0.28 20.45* pau wild!. light slope shrub 7.1 6.4 0.29 34.39 pau wild!. dark swamp young 5.2 0.31 sec. f. 20.248 pau wild!. medium hill fullgr. 6.8 6.4 0.32 sec. f. 24.48 pau wild!. light slope shrub 8.1 8.7 0.32 48?? pau wild!. 7.0 7.1 0.32 20.39* pau wild!. light down hill shrub 10.0 12.4 0.33 31.48 pau wild\. light slope shrub 6.7 5.7 0.35

Downloaded from Brill.com10/05/2021 07:35:18AM via free access Bosman - Wood properties of planted meranti trees (Shorea) 407 initial problems with cultivation of several of these species have been overcome with the knowledge ofthe essential symbiotic mycorrhiza and the use of cuttings in vegeta tive propagation (Ädjers & Otsamo 1996; Smits 1987). The properties and quality of the wood of plantation grown meranti (Shorea leprosula Miq. andS. parvifolia Dyer) compared to those of naturally grown trees have been the subject of recent studies (Bosman 1996; Bosman et al. 1994; Bosman & Baas 1996). Plantation grown trees had slightly less variable wood, but also a somewhat lower specific gravity than naturally grown trees. The most important result of these studies, however, is the finding of large variation within and among the trees studied. Similar variation has also been found for other fast growing tropical hardwoods (Ismail et al. 1995; Butterfieid et al. 1993). The rotation period for future meranti plantations may vary from 45 to 60 years (DBH = 50 cm) (Apannah & Weinland 1996). Weidelt (1996) advises cutting cycles of at least 35 to 40 years in polycyclic management systems. In planting experiments, especially with cuttings from clones, an early quality assessment of the selected clones and the resulting timber would save time and costs. Therefore, in this study, the varia tion of some wood properties within and between juvenile trees, in relation to other growth factors (means of propagation, micro-environmental factors, growth rate) is discussed and compared with the variation in full grown trees previously studied.

MATERIAL

This study used six-year-old planted dipterocarp trees from the '200 ha plot' near the Wanariset-Samboja station in East Kalimantan (Indonesia). The trees were selected from a large number of trees following the 'early potential plus-tree' selection method to get promising mother trees for progeny testing. The trees were coppiced in March and April 1995 to produce shoots for a study on vegetative propagation (Tolkamp 1996). Two discs, one at 1.30 m and one halfway up the bole, were taken from 28 of these trees for the present study on wood anatomy and specific gravity. This selection encom passed three species: Shorea leprosula Miq., S. parvifolia Dyer, and S. pauciflora King. Shorea leprosula (12 trees) and S. parvifolia (7 trees) both belong to the light red meranti group. The planting stock ofthese trees came from transplanted wildlings (6 and 4 trees, respectively), cuttings (5 and 3 trees) and a seedling (S.leprosula). Shorea pauciflora produces somewhat heavier wood and is classified as dark red meranti. Only transplanted wildlings (9 trees) were available for this species. The height was recorded each year for most of the trees, and the diameter over the last two years and some micro-environmental conditions at the time of planting were recorded for some of them (Table 1). Previously, twelve full-grown light red meranti trees, planted or from natural for ests, were studied for radial and longitudinal variation in wood anatomy and specific gravity (Bosman et al. 1994; Bosman 1996). Samples and data from approximately the same height, to compare with those from the six-year-old trees, are available for only four of these trees (Table 2).

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Table 2. Anatomical parameters and specific gravity in four full grown trees of Shorea leprosula at c. I m and c10se to the pith compared with averages in young (six-year-oId) trees of S. leprosula, S. parvifolia and S. paucijlora. Tree numbers and data of full grown trees from previous studies (Bosman et al. 1994; Bosman 1996). - n = number of trees; LRM =light red meranti; DRM =dark red meranti; SG = specific gravity; FW =fibre wall percentage; AV = area percentage ofvessels and canals.

Full grown trees (LRM) Tree number SO at 1 m FW at 1 m AVat 1 m (origin, age) near pith near pith near pith

no.4 (planted, 34) 0.29 45 5.9 no. 6 (natural) 0.20 39 6.7 no. 7 (planted,62) 0.22 40 9.2 no. 10 (planted,62) 0.32 54 12.6 Average 0.26 (n = 4) 45(n=4) 8.6 (n = 4)

Young trees Category SO average FW average AVaverage

S. leprosula - LRM 0.26 (n = 12) 47 (n = 2) 9.4 (n = 2) S. parvifolia - LRM 0.27 (n = 7) 45 (n = 1) 10.2 (n = I) S. pauciflora - DRM 0.29 (n = 9) 54 (n = 2) 9.4 (n = 2) cuttings - LRM 0.30 (n = 8) wildlings - LRM 0.24 (n = 10) seedling - LRM 0.28 (n = 1) wildlings - DRM 0.29 (n = 9)

METHODS

SampIes of approximately 1 cm 3 each were taken for anatomical studies from five trees (marked * in Table I). Discs were cut at 1.30 m and halfway up the bole and sampies were taken from two opposite radii, one sampIe near the pith and one near the bark. This resulted in 8 sampies per tree. In one tree, with a relatively large diameter (tree no. 20.39), an additional sample halfway along each radius was taken, resulting in 12 sampies for this tree. Three parameters were studied: the basic specific gravity, the cell wall percentage within the fibre tissue ('fibre wall percentage') and the area percentage of vessels and resin canals. The latter parameter is almost complementary to the area percentage of fibre tissue, and much easier to measure (Bosman et al. 1994). Methods of sectioning and measuring were the same as for the study on radial and longitudinal variation in older trees (Bosman et al. 1994; Bosman 1996). An image analyser (VIDAS System of Kontron Elektronik) was used for quantitative anatomy and the water displacement method of Olesen (1971) was used to measure green volumes for the basic specific gravity determination.

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In the five extensively studied trees the speeifie gravity of the sampie from the basal dise (at 1.30 m) near the bark was the closest to the average value for the whole tree. Thus, for the other 23 young trees the speeifie gravity was measured from a sampie taken at this loeation.

RESULTS

Variation within and between trees The variation for the studied parameters within the young trees is small, espeeially when eompared with the variation within full grown trees (Bosman et al. 1994; Bos- man 1996). No eonsistent patterns were found in radial or in longitudinal variation (Table 3). As in full grown trees (Bosman et al. 1994; Bosman 1996), a signifieant positive eorrelation was found between speeifie gravity and fibre wall pereentage. As expeeted, the averages for fibre wall pereentage and speeifie gravity are distinetly higher in the dark red meranti (S. pauciflora) than in the light red meranti (S. leprosula and S.

Table 3. Variation of the parameters studied within five trees. Included sampies: A = at 1.30 m, B = halfway the bole, T = tree total. Pattern: for A and B: radial pattern from pith to bark; for T: longitudinal pattern from pith-to-bark average at 1.30 m to pith-to-bark average at halfway the bole. -lep = Shorea leprosula; par = S. parvifolia; pau = S. pauciflora; i = increase; d = decrease; - = no consistent increase or decrease; FW = fibre wall pereentage; AV = area percentage of vessels and canals; SG = specific gravity.

0) 0) 0) OJ} 0) OJ} 0) OJ} 0) 0) Q OJ} Q OJ} OJ} '" 0; Q i5...... 0; E ...0; ...0; E ...0; ...0; E Ei 0) 0) 0) 0; ~ ~ ~ CZl ~ ..< 0- ~ ..< 0- "CZl ..< 0- 1.276 A 40-47 43 8.2-10.9 9.3 0.17-0.18 0.18 lep B 42-46 44 d 9.3-11.7 10.7 0.16-0.18 0.17 T 40-47 44 8.2-11.7 10.0 0.16-0.18 0.17 d

20.35 A 48-53 50 9.1-9.9 9.4 0.24 0.24 lep B 44-52 47 d 8.8-10.5 9.8 0.23-0.27 0.25 T 44-53 49 d 8.8-10.5 9.6 0.23-0.27 0.24

1.277 A 43-46 45 8.9-11.1 10.2 d 0.20-0.24 0.18 d par B 42-47 44 9.1-9.8 9.4 0.16-0.19 0.20 T 42-47 44 d 8.9-11.1 9.8 d 0.16-0.24 0.20

20.39 A 54-67 58 9.3-10.5 9.7 0.28-0.36 0.32 pau B 57-66 61 8.4-12.1 10.5 0.30-0.37 0.34 T 54-67 59 8.4-12.1 10.1 0.28-0.37 0.33

20.45 A 48-55 50 8.5-9.8 9.1 d 0.28-0.33 0.31 d pau B 50-60 56 8.4-9.6 9.0 d 0.27-0.29 0.28 T 48-60 53 8.4-9.8 9.0 d 0.27-0.33 0.29 d

Downloaded from Brill.com10/05/2021 07:35:18AM via free access 410 IAWA Journal, VoI. 18 (4),1997 parvifolia). Analysis of variance of specific gravity and fibre wall percentage shows that, within each of the two meranti groups, the variance between trees is significantly larger than the variance within trees. For the area percentage of vessels and canals the variance between trees does not differ significantly from that within trees.

Variation within and between species Table 1 presents the specific gravity of all trees studied. As was expected, the high est values were found for S. pauciflora (0.31), with values of 0.26 for S. leprosula, and 0.27 for S. parvifolia. Analysis of variance of the specific gravity of all studied species shows that the differences within the species are significantly larger than the differ ences between the species.

Variation in young trees compared with Jull grown trees For all parameters the values for young trees fall within the range found in the full grown trees available for comparison (Table 2). Averages for specific gravity and fibre wall percentage correspond in the young and full grown trees of light red meranti and in the young trees of dark red meranti. The average area percentage of vessels and canals is relatively high in the six-year-old trees, when compared with that in the full grown trees.

Specijic gravity in relation to growth rate, site factors and means of planting stock production Height ofthe trees varies from 4.5-10.0 m, with an average of7.7 m. The averages per species do not differ much (8.0 m in S. leprosula, 7.3 m in S. parvifolia and 7.5 m in S. pauciflora). The diameter, which has only been recorded for the transplanted wildlings, varies from 5.2-8.7(-12.4) cm, with an average on cm (6.6 cm, 6.1 cm and 7.6 cm in the respective species) (Table 1). No significant correlation was found between specific gravity and the two avail able growth rate parameters, height and diameter. Analysis of variance of height (n = 27) and diameter (n = 18) shows that the variance between the three species is not significantly larger than the variance within the species. The micro-environmental factors recorded (only for transplanted wildlings, see Table 1) seem to be related to the specific gravity in at least two trees of the light red meranti group (no. 1.277 and 1.276). They were planted in a dark, wet spot in primary forest and have the lowest values for specific gravity (0.17 and 0.20, respectively), far below the average for wildlings of light red meranti (0.24). Also, these two trees have relatively small diameters (5.4 and 6.1 cm). Two trees of S. pauciflora also were planted in wet spots, but in young secondary forest. One of these (no. 36.54, in a relatively light spot) has the lowest value (0.27) for specific gravity for this species (species aver age ofO.31). The other (no. 34.39, in a relatively dark spot) has a specific gravity of 0.31, equalling the average. Most light red meranti trees grown from cuttings show higher values for specific gravity than those grown from transplanted wildlings, except for one cuuing, no. s3.20, with a relatively low value and one wildling, no. 24.27, with a high value (Table 1).

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Accordingly, the average specific gravity for trees from cuttings is higher (0.30) than that for the six-year-old trees from transplanted wildlings (0.24) and higher than that for juvenile wood of the fuH grown trees (0.26; Table 2). The one tree grown from seed (no. p2, S. leprosula) has a specific gravity of 0.28, close to the average of the species (0.26).

DISCUSSION AND CONCLUSION

The most striking resuIt of this study is the large variation of fibre wall percentage and specific gravity between trees of the same species. This variation may offer possibili ties for selecting superior clones for further planting experiments. However, further research is needed into the influence of environmental factors, because the nature of this influence may differ for different species. In Eucalyptus and Quercus, for instance, the environmental variation appears to be overshadowed by genetic diversity (Mosedale et al. 1996; Wilkes 1988), while in teak the opposite seems to be true (Purkayastha et al. 1973). Also, the influence, interaction and heritability of suitable selection pa rameters need to be studied. Selection on specific gravity alone seems to be most straight forward, because this parameter usually is considered to be most important for strength and durability, but it may be feasible to include other parameters, such as fibre wall percentage and mechanical properties (Zhang 1995; Zhang & Chui 1996). For all three parameters, the values found in the six-year-old trees correspond closely to those found in the four full grown trees, which suggests that at least at this age these superior six-year-old trees do not produce wood significantly better or worse than that of the full grown trees. This is opposed to the findings of Butterfieid et al. (1993), who found significant differences between young (5.5 -year-old) plantation grown trees and naturally grown trees. Compared to the full grown trees, the planted trees showed a lower average specific gravity in Hyeronima and less prominent radial increase in specific gravity in Vochysia. In the four full-grown trees (Table 2), the values of specific gravity and fibre wall percentage found close to the pith appeared to be positively correlated with those found at 6-13 cm from the pith. Thus, specific gravity and fibre wall percentages of juve nile wood in Shorea leprosula may have a predictive value for these characteristics in later-formed wood. InitiaHy macerations were made to measure fibre lengths. In the four fuH grown trees this parameter appeared to be significantly and positively correlated with specific gravity and fibre wall percentage. However, no significant correlation was found be tween the fibre lengths dose to the pith and those at 6-13 cm from the pith. Therefore, this parameter was excluded from further studies. No significant correlation was found between specific gravity and height or diam eter, suggesting no apparent correlation between specific gravity and growth rate. This is in part surprising, because generally a correlation between specific gravity and ra dial growth rate is assumed, although this may depend upon species (Taylor & Wooten 1973; Purkayastha et al. 1982; Land et al. 1983; Zobel & Van Buijtenen 1989; Sedenio 1991; De Castro et al. 1993). In this study, however, the diameters of only 18 trees were available.

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The scanty data available on micro-environmental conditions at the time of planting suggest that dark and wet spots in primary forest are unfavourable for higher specific gravity and, somewhat less so, for diameter increment. The suggestion that trees from cuttings perform somewhat better than transplanted wildlings, because they show rela tively high values for specific gravity, can only be confirmed when the influence of micro-environmental conditions on the specific gravity and the diameter increment of these trees is known.

ACKNOWLEDGEMENTS

This study has been financed by the Tropenbos Foundation and was executed at the Rijksherbarium / Hortus Botanicus of Leiden University. I thank Mr. Willie Srnits and all other staff members of the Wanariset in East Kalimantan for their help in providing sampies and data and for their warm wel come and fruitful discussions during a short stay at the research station.

REFERENCES

Adjers, G. & A. Otsamo. 1996. Seedling production methods of dipterocarps. In: A. Schulte & D. Schöne (eds.), Dipterocarp Forest Ecosystems: towards sustainable management: 391- 410. World Scientific Publishing Co. Pte. Ltd., Singapore. Appanah, S. & G. Weinland. 1996. Experience with planting dipterocarps in peninsular Malaysia. In: A. Schulte & D. Schöne (eds.), Dipterocarp Forest Ecosystems: towards sustainable management: 411-445. World Scientific Publishing Co. Pte. Ltd., Singapore. Bosman, M.T.M. 1996. Longitudinal variation in selected wood properties of naturally and plantation grown light red meranti (Shorea leprosula and S. parvifolia, Dipterocarpaceae). IAWA 1. 17: 5-14. Bosman, M.T. M. & P. Baas. 1996. Wood structure and properties of naturally and plantation grown light red meranti. In: A. Schulte & D. Schöne (eds.), Dipterocarp Forest Ecosystems: towards sustainable management: 578-590. World Scientific Publishing Co. Pte. Ltd., Sin gapore. Bosman, M.T.M., 1. de Kort, M.K. van Genderen & P. Baas. 1994. Radial variation in wood properties of naturally and plantation grown light red meranti (Shorea, Dipterocarpaceae). IAWA J. 15: 111-120. Butterfieid, R.P., RP. Crook, R Adams & R. Morris. 1993. Radial variation in wood specific gravity, fibre length and vessel area for two Central American hardwoods: Hyeronima alchorneoides and Vochysia guatemalensis: natural and plantation-grown trees. IAWA J. 14: 153-161. De Castro, F, G.B. Williamson & RM. De Jesus. 1993. Radial variation in the wood specific gravity of Joannesia princeps: the roles of age and diameter. Biotropica 25: 176-182. Ismail, J., M.Z. Jusoh & M.H. Sahri. 1995. Anatomical variation in planted Kelempayan (Neolamarckia cadamba, Rubiaceae). IAWA J. 16: 277-287. Land, S.B., S.G. Dicke, G.A. Tuskan & P.E. Patterson. 1983. Genetic, site and within-tree vari ation in specific gravity and moisture content in young sycamore trees. Tappi 66: 149-155. Mosedale, J.R., B. Charrier & G. Janin. 1996. Genetic control of wood colour, density and heartwood ellagitannin concentration in European oak (Quercus petraea and Q. robur). Forestry 69 (2): 11-124. Oleson, P. O. 1971. The water displacement method. A fast and accurate method of deterrnining the green volume of wood sampies. Forest Tree Improvement, Arboretet Horsholm 3: 3-23.

Downloaded from Brill.com10/05/2021 07:35:18AM via free access Bosman - Wood properties of planted meranti trees (Shorea) 413

Purkayastha, S.K., R.D. Tandon & K.R. Rao. 1973. A note on the variation in wood density in some 36-year-old teak trees from different seed origins. Indian For. 99: 215-217. Purkayastha, S. K., S. P. Agrawal, R. D. Tamdon & L. Chauhan. 1982. Studies on the variation in wood quality of Eucalyptus tereticornis Sm. trees grown in different plantations. Part I: wood specific gravity. Ind. For. Rec., Wood Anat. 3: 1-27. Sedenio, P.E. 1991. Influence of growth rate on specific gravity, fibre length and cell wall thick ness of an even-aged mahogany stand (Swietenia macrophylla King). CMU J. of Sci. 4: 2-20. Smits, W.Th.M. 1987. Production of dipterocarp planting stocks in nurseries. In: A.J.H.G. Kos termans (ed.), Proc. Third Round Table Conf. Dipterocarps: 153-157. UNESCO Regional Office for Science and Technology for Southeast Asia, Jakarta. Taylor, EW. & T.E. Wooten. 1973. Wood property variation of Mississippi delta hardwoods. Wood & Fibre 5: 2-13. Tolkamp, G.w. 1996. Early selection and vegetative propagation of six year old superior dip terocarp trees through cuttings from stumps. Wanariset technical paper nr. 1996-11. The International MoF-Tropenbos Kalimantan Project, Balikpapan, Indonesia. Weidelt, H.J. 1996. Sustainable management of dipterocarp forests - opportunities and con straints. In: A. Schulte & D. Schöne (eds.), Dipterocarp Forest Ecosystems: towards sus tainable management: 249-273. World Scientific Publishing Co. Pte. Ltd., Singapore. Wilkes, J. 1988. Variations in wood anatomy within species of Eucalyptus. IAWA Bull. n. s. 9: 13-23. Zhang, S.Y. 1995. Effect of growth rate on wood specific gravity and selected mechanical prop erties in individual species from distinct wood categories. Wood Sci. & Techno!. 29: 451- 465. Zhang, S. Y. & Y. H. Chui. 1996. Selecting dry fibre weight for higher and better quality jack pine fibre production. Wood & Fiber Sci. 28: 146-152. Zobel, B.J. & J.P. van Buijtenen. 1989. Wood variation: Its cause and contro!. Springer Verlag, Berlin.

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