Osunkoya2007
Data contributor: Olusegun O. Osunkoya
Email: segun.osunkoya@jcu.edu.au
Address:
- College of Marine and Environmental Sciences, James Cook University, P.O. Box 6811, Cairns Queensland 4870, Australia
Citation: Osunkoya OO, Omar-Ali K, Amit N, Dayan J, Daud DS and Sheng TK (2007). 'Comparative height crown allometry and mechanical design in 22 tree species of Kuala Belalong rainforest, Brunei, Borneo.' American Journal of Botany, 94(12), pp. 1951-1962.
Abstract: In rainforests, trunk size, strength, crown position, and geometry of a tree affect light interception and the likelihood of mechanical failure. Allometric relationships of tree diameter, wood density, and crown architecture vs. height are described for a diverse range of rainforest trees in Brunei, northern Borneo. The understory species follow a geometric model in their diameter-height relationship (slope, {beta} = 1.08), while the stress-elasticity models prevail ({beta} = 1.27-1.61) for the midcanopy and canopy/emergent species. These relationships changed with ontogeny, especially for the understory species. Within species, the tree stability safety factor ({SSF)} and relative crown width decreased exponentially with increasing tree height. These trends failed to emerge in across-species comparisons and were reversed at a common (low) height. Across species, the relative crown depth decreased with maximum potential height and was indistinguishable at a common (low) height. Crown architectural traits influence {SSF} more than structural property of wood density. These findings emphasize the importance of applying a common reference size in comparative studies and suggest that forest trees (especially the understory group) may adapt to low light by having deeper rather than wider crowns due to an efficient distribution and geometry of their foliage.
The dataset includes records for 367 individuals from 22 species belonging to 13 family(ies), presenting 1 functional type(s), growing in 1 condition(s) within 1 major type(s) of habitat, with data included for the following variables:
| Variable | Label | Units | N | Min | Median | Max |
|---|---|---|---|---|---|---|
| latitude | Latitude | deg | 367 | 4.5 | 4.5 | 4.5 |
| longitude | Longitude | deg | 367 | 115 | 115 | 115 |
| a.stbh | Stem area at breast height | m2 | 367 | 0.002 | 0.0074 | 0.77 |
| a.cp | Crown area | m2 | 354 | 0.36 | 16 | 207 |
| h.t | Height | m | 367 | 2.7 | 12 | 53 |
| h.c | Height to crown base | m | 363 | 0 | 7 | 40 |
| d.bh | Dbh | m | 367 | 0.05 | 0.097 | 0.99 |
| h.bh | Height of d.bh measurement | m | 367 | 1.3 | 1.3 | 1.3 |
| d.cr | Crown width | m | 354 | 0.8 | 4.2 | 20 |
| c.d | Crown depth | m | 363 | 0.17 | 5.1 | 24 |
And locally within the country:
The sites sampled are:
| Location | Longitude | Latitude | Vegetation |
|---|---|---|---|
| Brunei, Borneo | 115.1667 | 4.5 | Tropical rainforest |
The growing conditions of sampled plants was:
| Location | Grouping | growingCondition |
|---|---|---|
| Brunei, Borneo | growth_form = canopy | field wild |
| Brunei, Borneo | growth_form = subcanopy | field wild |
| Brunei, Borneo | growth_form = understorey | field wild |
| Species | Family | Pft |
|---|---|---|
| Horsfieldia polyspherulaa | Myristicaceae | evergreen angiosperm |
| Knema ashitoniia | Myristicaceae | evergreen angiosperm |
| Litsea ferrugiinea | Lauraceae | evergreen angiosperm |
| Payena sp | Sapotaceae | evergreen angiosperm |
| Shorea parvifolia | Dipterocarpaceae | evergreen angiosperm |
| Syzygium sp. | Myritaceae. | evergreen angiosperm |
| Syzygium caudatum | Myritaceae | evergreen angiosperm |
| Dacryodes apiculata | Burseraceae | evergreen angiosperm |
| Dillenia excelsa | Dilleniaceae | evergreen angiosperm |
| Diospyros borneensis | Ebanaceae | evergreen angiosperm |
| Mallotus sp. | Euphorbiaceae | evergreen angiosperm |
| Noescortechinia kingii | Euphorbiaceae | evergreen angiosperm |
| Aporusa elemeri | Euphorbiaceae | evergreen angiosperm |
| Aporusa grandistipula | Euphorbiaceae | evergreen angiosperm |
| Aporusa subcaudata | Euphorbiaceae | evergreen angiosperm |
| Chionanthus spicatusi | Oleaceae | evergreen angiosperm |
| Fordia sp. | Fabaceae | evergreen angiosperm |
| Fordia splendidissima | Fabaceae | evergreen angiosperm |
| Ixora grandifolia | Rubiaceae | evergreen angiosperm |
| Mallotus eucaustus | Euphorbiaceae | evergreen angiosperm |
| Mallotus wreyi | Euphorbiaceae | evergreen angiosperm |
| Urophyllum arboreum | Rubiaceae | evergreen angiosperm |
Sampling strategy: All trees > 5 cm in diameter in a 1 ha permamant plot were sampled.
Stem cross sectional area: Tree diameter at breast height determined, using diameter tapes.
Height: Tree height determined using clinometers. Crown depth is the difference between tree height and fork height. Fork height itself is defined as distance between the stem base and the lowest major brach
Crown area: Crown diameter were measured in four directions, and crown projection area estimated as a function of tree fork and crown heights and crown width; see Osunkoya et al 2007 for details.
Growth environment: Mixed dipterocarp rainforest.
Year collected: 2004
Acknowledgements: P. Becker initially set up the permanent plots used
This is how the study Osunkoya2007 fits in the entire dataset (grey). each colour represents a species. A legend of species names with colours is included at the end for reports with 1 < n < 20 species.
