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A large scale solid wood flooring factory is to be established in Sri Lanka. On the planning
stage of this industry it was found that information on wood properties of local timbers such as
Hevea brasiliensis for wood flooring are not available. Hence, the present study has been
conducted to gather data on selected wood properties of Rubber wood and how the wood
quality changes with growth rate of trees.
Hevea brasiliensis 35 year old trees were selected from three size classes: suppressed, codominant and dominant. Sample disks were removed at top (80%), middle (50%) and breast
height of the log length. Radial variations were also studied at percentage distances from pith
to bark.
Wood quality was assessed by ring specific gravity. Ring width remained more or less constant
from pith towards bark with slight decrease towards the bark indicating the uniform growth
rate. However no specific variation was observed in ring specific gravity. This radial variation
of growth rate and specific gravity was similar in all three size classes.
Application of Rubber wood as solid wood elements for flooring was experimentally assessed
by hardness to loads applied to the wood and specific gravity. The mean specific gravity of
suppressed, co-dominant and dominant trees were 0.564, 0.629 and 0.631 respectively
indicating that the specific gravity of Rubber wood lies within the required standard for flooring
which is 0.5-0.75. In the hardness test, it was observed that all three size classes generally show
a gradual increase in hardness from pith towards bark. The values of average hardness of
suppressed, co dominant and dominant trees were 341 kgf, 405 kgf and 433 kgf, hence co
dominant and dominant trees have hardness values above 400 kgf, the standard value for wood
flooring. These results indicate that Hevea brasiliensis has wood properties which are within
European standard and Indian standard for manufacture of wooden flooring.
