Variation of Heartwood and Sapwood and Growth Characteristics of Artificial Dahurian Larch
We selected 10 sample plots of dahurian larch ( Lar ix gmelinii Rupr.) plantations from Lilin Farm in Wuying Forest Bureau in Heilongjiang Province , and three trees with dominant tree , average tree and suppressed trees .Wood discs were cut at intervals of 1 m along the stem of felled tree .We measured the diameter outside and inside bark , overall ring num-ber, sapwood ring number , sapwood width at two directions of northeast and southwest .We studied the variations in heart-wood and sapwood among two orientations , trees and stands , from base to the top of the tree , and growth correlation with individual tree variables using normal distribution test , t test, nonparametric test, variance analysis, multiple comparison, and correlation and regression analysis methods .There were no significant variations among two orientations ( P>0.05 ) . There are significant variations among trees and stands ( P<0.05) and diameter at breast better explained the variations of heartwood and sapwood among trees .Heartwood radius , heartwood area , sapwood area decreased from the stump to top of the tree height for dahurian larch .However , sapwood width was bigger at stem base , remained relatively constant above 1 m to stem, and then decreased at top of the tree .Heartwood radius, heartwood area, sapwood width, and sapwood area had significant correlation with cambial age and outside and inside bark diameter (P<0.0001).Ring number of heartwood and sapwood increased with the increase of cambial age .Cambial age could account for over 90%of the variation of heartwood ring number , only 46%of the variation of sapwood ring number .
Larix gameliniiHeartwood variationSapwood variationGrowth characteristic of heart woodGrowth characteristic of sapwood
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