关键词: 红锥人工林, 木材, 生长应变, 变异性, 生长弱化处理

Abstract:

Objective: This study aims to investigate the variation of growth strain in standing Castanopsis hystrix trees and examine the influence of growth weakening treatments on this strain, with the objective of developing strategies to mitigate growth stress. Method: Trees of different ages and dominance grades (grade A: dominant and subdominant trees; grade B: intermediate trees; grade C: suppressed and dying trees; grade D: dead standing trees) were selected with the plantation in the southern subtropical region of China. The growth strain indices of standing trees, which reflect growth stress that cannot be directly measured, were determined in different seasons, and their variation patterns were analyzed. This study examined the effects of growth parameters, trunk orientations, trunk heights, and growth weakening treatments (treatment A: ringbarking at the trunk base; treatment B: injecting glyphosate at the trunk base) on growth strain. Result: Significant differences in growth strain were observed in C. hystrix standing trees with respect to dominance grades, seasons, and tree ages. The growth strain diminished as the dominance grades decreased, with the highest and lowest values occurring in summer and spring, respectively. The variation in summer was significantly greater than in other seasons. Growth strain was significantly positively correlated with average soil temperature, air temperature, and monthly precipitation during the measurement month, while it was significantly negatively correlated with soil moisture and air humidity. Growth strain increased with tree age and exhibited significant circumferential variability. Below 9.0 m of trunk height in fallen trees, the differences in growth strain between different trunk heights were not significant. Compared to the control group (no growth weakening treatment), growth weakening treatments significantly reduced growth strain one year later, with Treatment A and B reducing growth strain by 50% and 30%, respectively. Conclusion: The growth strain of C. hystrix is significantly influenced by tree characteristics such as dominance grade, season, tree age, trunk orientation, and meteorological factors such as humidity, temperature, and precipitation during the measurement months. Harvesting outside the summer season is beneficial for reducing growth stress in timber. The growth strain of C. hystrix was not significantly correlated with the height-diameter ratio of trees, and the regulation of tree density could not significantly reduce the growth stress. growth weakening treatments (ringbarking at the trunk base or injecting glyphosate growth inhibitor) can significantly reduce growth strain.

Key words: Castanopsis hystrix, plantation, growth strain, variability, growth weakening treatments