By: Ayodele O. C.; Adenaiya A. O.; Oyediji O. T.; Ogunsanwo O. Y.;
Abstract:
The rate of depletion of the economic timber species in the forests makes imperative the need to search
for alternative timber species. Polyalthia longifolia is well known for its ornamental and medicinal
services but little is known about its wood properties which can aid in ascertaining its suitability for
timber. Therefore, this study investigated the between and within-tree variation in selected physical
properties of P. longifolia with a view to identifying its suitability as a timber species. Five 21-yearold P. longifolia trees (T) were harvested from Akobo area in Ibadan, Nigeria. Bolts of 60 cm length
were obtained from the breast height of the trees; central planks were obtained from each bolt and each
central plank was radially partitioned into three radial zones (RZ): innerwood, middlewood and
outerwood. Test samples were collected from each radial zone and the Moisture content (MC), Specific
gravity (SG), Longitudinal shrinkage (LS), Tangential Shrinkage (TS), Radial Shrinkage (RS), and
Volumetric shrinkage (VS) were evaluated. Using a Factorial design, the data obtained were subjected
to one-way analysis of variance (ANOVA) at 5% probability level. The mean MC was 13.76%, ranging
from 13.11% (innerwood) to 14.68% (outerwood) and also ranged from 13.09% (T1) to 15.29% (T4)
between trees. The SG was highest in the inner wood (0.57) and T3 (0.54), and least in the middle wood
(0.49) and T1 (0.49). The LS decreased consistently from the inner wood (0.44%) to the outerwood
(0.23%).The mean TS and RS both varied radially from 3.95% and 3.37% (middle wood) to 4.65% and
3.77% (outerwood), respectively. The mean VS was 7.96%, ranging from 8.13% (innerwood) to 8.42%
(outerwood), while it was highest in T5 (9.07%) and least in T4 (7.47%).The wood had a uniform MC,
LS, TS and VS between and within-tree (p>0.05), while it significantly varied in its SG within-tree, and
RS between trees (p<0.05). Based on the results, it is concluded that P. longifolia wood exhibited
properties, which compare well with those of some other commercial timber species, hence, the wood
is in no way inferior to some of the highly sought timber species.
Keywords: Polyalthia longifolia; moisture content; moisture content; moisture content;
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