1. Introduction
Wood density (or, as usually measured, wood specific gravity) is a key plant trait which is inversely related to mean growth rates and also tends to correlate with drought tolerance and shade tolerance. As part of a larger study on the ecological and biogeographic distribution of tree species across the Indonesian archipelago, we measured twig wood for all 257 morphotypes tree species occurring as individuals (> 10 cm DBH) in six 0.25-ha plots in lowland dipterocarp forest in the Gunung Palung National Park in West Kalimantan, Indonesian.
Wood density (or, as usually measured, wood specific gravity) is a key plant trait which is inversely related to mean growth rates and also tends to correlate with drought tolerance and shade tolerance. As part of a larger study on the ecological and biogeographic distribution of tree species across the Indonesian archipelago, we measured twig wood for all 257 morphotypes tree species occurring as individuals (> 10 cm DBH) in six 0.25-ha plots in lowland dipterocarp forest in the Gunung Palung National Park in West Kalimantan, Indonesian.
2.
Methods
Six plots of
0.25 ha were set up in lowland dipterocarp forest (100-300 m ASL) near the Riam
Parit area of the park. Three plots were in the valleys, on rich alluvial soil,
and three plots were on nearby ridges, with shallower, sandier soil. All
trees were measured for diameter and marked permanently with tree tags. We
collected sterile (or fertile where possible) twigs for identification and
these were subsequently matched at Herbarium Bogoriense. Two living twigs
of 1 cm minimum diameter were collected from a representative tree for each
species by tree limbers, during the preparation of botanical and DNA vouchers,
and cut to 10 cm lengths.
Following Cornelissen et al. (2003), in the lab, we submerged the twig sections in water in a container on a balance to determine displaced volume, and then dried the sections in an oven and weighed them. From the two samples per species, we calculated a mean wood specific gravity.
3. Results
The mean wood density for all 257 species was 0.6135 (SE = 0.0067), with the least dense species being Durio oxleyanus Griff. (at 0.313) and the densest being Reinwardtiodendron humile (Hassk.) Mabb. (at 0.859) (Table 1). The mean of the least dense family was 0.445, for Podocarpaceae, and the most dense was 0.810 for Ochnaceae (Table 2). There was asignificant difference in wood density among the trees classed by plot (Fig. 2), but not when classed by site (high ridge, vs low valley; Fig. 3).
The mean wood density for all 257 species was 0.6135 (SE = 0.0067), with the least dense species being Durio oxleyanus Griff. (at 0.313) and the densest being Reinwardtiodendron humile (Hassk.) Mabb. (at 0.859) (Table 1). The mean of the least dense family was 0.445, for Podocarpaceae, and the most dense was 0.810 for Ochnaceae (Table 2). There was asignificant difference in wood density among the trees classed by plot (Fig. 2), but not when classed by site (high ridge, vs low valley; Fig. 3).
4. Conclusion
We expect the more drought stressed sites to have trees with slower growing, more drought tolerant species. While there was no overall significant difference between trees in high and low plots, the one real ‘real’ hilltop plot (plot B), with shallow, rocky soil, had very high wood density (Fig. 2). The finding that at least some of the hilltop plots had high wood density has an implication for carbon storage in the large degraded areas of Borneo: in these degraded areas, there is often no primary forest left except small patches on the tops of hills. These are likely to have a relatively high carbon density for their area, and should be preserved if at all possible.
We expect the more drought stressed sites to have trees with slower growing, more drought tolerant species. While there was no overall significant difference between trees in high and low plots, the one real ‘real’ hilltop plot (plot B), with shallow, rocky soil, had very high wood density (Fig. 2). The finding that at least some of the hilltop plots had high wood density has an implication for carbon storage in the large degraded areas of Borneo: in these degraded areas, there is often no primary forest left except small patches on the tops of hills. These are likely to have a relatively high carbon density for their area, and should be preserved if at all possible.
5. References
J. H. C. Cornelissen, S. Lavorel, E. Garnier, S. Díaz, N. Buchmann, D. E. Gurvich, P. B. Reich, H. Ter Steege, H. D. Morgan, M. G. A. vander Heijden, J. G. Pausas and H. Poorter. 2003. A handbook of protocols for standardised and easy measurement of plant functional traits world wide. Australian Journal of Botany 51 (4) 335-380.
J. H. C. Cornelissen, S. Lavorel, E. Garnier, S. Díaz, N. Buchmann, D. E. Gurvich, P. B. Reich, H. Ter Steege, H. D. Morgan, M. G. A. vander Heijden, J. G. Pausas and H. Poorter. 2003. A handbook of protocols for standardised and easy measurement of plant functional traits world wide. Australian Journal of Botany 51 (4) 335-380.
6. For
more information, visit : http://xmalesia.info
Family Species Mean SE
Malvaceae Durio
oxleyanus Griff. 0.313 NA
Anacardiaceae Parishia insignis Hook.f. 0.341 NA
Dipterocarpaceae Shorea domatiosa P. S. Ashton 0.359 NA
Myrtaceae Syzygium
leptostemon (Korth.) Merr.&Perry 0.366 NA
Apocynaceae Dyera
polyphylla (Miq.) Steenis 0.379 NA
NA NA 0.385 NA
Burseraceae Santiria
tomentosa Bl. 0.392 NA
Dipterocarpaceae Shorea parvistipulata Heim. 0.395 NA
Myrtaceae Aromadendron
elegans Blume 0.402 NA
Dipterocarpaceae Dipterocarpus tempehes Sloot. 0.415 NA
...
Ochnaceae Gomphia serrata (Gaertn.) Kanis 0.811 NA
Ochnaceae Gomphia serrata (Gaertn.) Kanis 0.811 NA
Fabaceae Dialium 0.813 NA
Melastomataceae Memecylon myrsinoides Bl. 0.815 0.002
Clusiaceae Garcinia
rostrata (Hassk.) Miq. 0.815
0.006
Clusiaceae Garcinia
balicca Miq. 0.819
NA
Clusiaceae Garcinia
rigida Miq. 0.824
NA
Rubiaceae Ixora
elliptica R. Br.et Ridl. 0.830
NA
Myrtaceae Rhodamnia
cinerea Jack. 0.832
NA
Polygalaceae Xanthophyllum stipitatum A. W. Benn 0.842 NA
Meliaceae Reinwardtiodendron
humile (Hassk.) Mabb. 0.860 NA
Fig. 1. Distribution of wood densities for 257 taxa.
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