Abstract:

Variation in growth ring width,wood basic density and hot extracts content of rubbertree were reported in this paper and its wood improvement and processing utilization of its wood resources were also discussed.The significant difference in wood basic density was found between the individuals within clones(DF95,PR107 and PRIM600),but not found among clones.Wood basic density in radial direction within trees of PR107 first increased gradually,levelled off after the 6～7th growth ring and decreased a little within over matured wood near bark.Wood basic density in longitudinal direction within trees augmented from base to top until its maximum,then reduced.Variant range of wood basic density within trees varied from 0.470 g·cm^-3 to 0.650 g·cm^-1,its variant coefficient was within range of 3.0% to 8.2%. Variant range of wood basic density between trees varied from 0.421 g·cm^-1 to 0.580 g·cm^-3 and its variant coefficient was within range of 5.16% to 7.05%.The hot extracted content of rubberwood was high compared to the others hardwoods and it varied from 6.65% to 11.53% within trees and among trees.The positive correlation equations of extracted wood density with unextracted wood density of three clones of rubbertree were significant at 0.01 level or 0.001 level.Relationship models of growth ring width and wood basic density of rubbertree clones with the tree age were expressed with equations of 5～6 times multinomial.Their relationship coefficients were from 0.8362 to 0.9787.

Key words: Hevea brasiliensis (rubbertree), Wood basic density, Extractives, Growth ring width, Variation, Modelling equation