Longitudinal Growth Strains in Melia dubia
Logs of many fast-grown tree species develop end splitting immediately after felling, and timber from such logs suffers from excessive warping and twisting on sawing. Such distortions are attributed to the presence of high magnitude of inherent growth str
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Abstract Logs of many fast-grown tree species develop end splitting immediately after felling, and timber from such logs suffers from excessive warping and twisting on sawing. Such distortions are attributed to the presence of high magnitude of inherent growth stresses. This results in low recovery of quality sawn material and therefore devalues a tree species for timber purposes. For the efficient utilization of any timber species, prior knowledge on the intensity and distribution of growth stresses in trees is vital. Melia dubia is increasingly gaining popularity as the plantation species because of its fast growth and is becoming a preferred species for plywood manufacturing. For ensuring the suitability of the species as a timber for other applications, the propensity of growth stresses needs to be known. Since inherent growth stresses cannot be measured directly, in lieu longitudinal growth strains are measured by relieving the stresses. In this paper, magnitude of longitudinal growth strain measured in trees and logs of M. dubia from three age groups growing in different locations are presented. The longitudinal growth strains were measured using wire strain gauge method. The magnitude of growth strain was ranging from 56 to 730 microstrains. The observed growth strains are in the range which does not raise a serious concern in processing and utilizing this species as timber. Keywords Growth stress
Growth strain Melia dubia Plantation Timber
Introduction Plantation forestry is rapidly becoming a major source for solid wood, wood-based composites and engineered wood. Consequently, there has been a significant emphasis on obtaining higher value wood products from fast-grown plantation timbers. One of the important concerns with such material is the enormous S. Sharma S. Sumbali P. Aggarwal S.S. Chauhan (&) Institute of Wood Science and Technology, Bengaluru, India e-mail: [email protected]; [email protected] © Springer Nature Singapore Pte Ltd. 2017 K.K. Pandey et al. (eds.), Wood is Good, DOI 10.1007/978-981-10-3115-1_6
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variability in wood quality between and within species. Many plantation species like Eucalyptus spp., Acacia auriculiformis, Nothofagus spp. are prone to have relatively high magnitude of growth stresses, excessive shrinkage, processing difficulties, etc., limiting their utility for solid wood products. Understanding the natural variability of such wood quality traits and their influence on product qualities plays a critical role in effective utilization of such timbers. High magnitude of longitudinal growth stresses has a significant implication in recovery and processing of high quality timber. Though the longitudinal growth stresses are inherent to all trees, their magnitude varies between species to species and also within species. These stresses cause ring shake and brittle heart in standing trees, end splitting in logs within a short span of felling a tree, severe warping in timber immediately after sawing and twisting and cracking in timber during
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