腐烂等级、径级对阔叶红松林木质残体含水率和密度的影响

【目的】含水率和密度是木质残体重要的物理性质。为了更合理地评估森林生态系统养分含量和生产力变化,对阔叶红松林木质残体的含水率和密度进行研究。【方法】以东北典型阔叶红松林中主要树种红松、臭冷杉、枫桦、槭树、椴树、水曲柳、榆树的木质残体为研究对象, 对5个腐烂等级(Ⅰ—Ⅴ)下的3个径级(ⅰ—ⅲ)进行取样, 分析腐烂等级、径级、树种、结构组分(边材、心材)对木质残体含水率、密度的影响。【结果】随腐烂等级的增加, 木质残体含水率显著增加, 密度显著降低; 除腐烂等级Ⅲ和总体木质残体边材密度显著高于心材外, 其余腐烂等级木质残体含水率、密度在边材与心材之间均无显著差异; 除腐烂等级Ⅰ的木质残体心材含水率外, 其余腐烂等级木质残体边材、心材的含水率和密度在部分树种之间均有显著差异。木质残体含水率、密度在径级间均无显著差异; 径级ⅰ的木质残体边材、心材含水率在部分树种间有显著差异, 径级ⅰ、ⅲ的木质残体边材、心材的密度在部分树种间均有显著差异。【结论】受不同因素的影响,阔叶红松林木质残体的含水率、密度有不同的变化规律, 且腐烂等级以及树种是导致木质残体分解过程中引起含水率、密度显著变化的重要因素。

Effects of decay class and diameter class on moisture content and wood density in a typical mixed broadleaf-Korean pine forest

【Objective】Moisture content and wood density are important physical properties of woody debris.However,the effects of decay class and diameter class on the wood density and moisture content of the main species in a typical mixed broadleaf-Korean pine(Pinus koraiensis)forest remain unclear.This study provides basic data on the moisture content and wood density of sapwood and heartwood of the main tree species in a typical mixed broadleaf-Korean pine forest and examines the variation patterns of moisture content and wood density with decay class and diameter class.【Method】The main tree species,Pinus koraiensis,Abies nephrolepis,Betula costata,Acer spp.,Tilia spp.,Fraxinus mandshurica and Ulmus spp.in the mixed forest were chosen for this study.The study samples were divided into five decay classes(Ⅰ-Ⅴ),and three diameter classes(ⅰ-ⅲ)were sampled for each decay class.The study aimed to explore the effects of decay class and diameter class on the moisture content and wood density of the different structural components(sapwood and heartwood)of the main tree species.【Result】The moisture content increased with increasing decay class,but the wood density decreased significantly.The wood density of sapwood was significantly higher than that of the heartwood in decay classⅢand overall;however,in the other decay classes,the wood density did not significantly differ between sapwood and heartwood.The moisture content and wood density of sapwood and heartwood were significantly different among some tree species in most decay classes.There was no significant difference in moisture content and wood density among the diameter classes.The moisture content of sapwood and heartwood was significantly different among some tree species in diameter classⅰ,and the wood density of sapwood and heartwood was significantly different among some tree species in diameter classⅰandⅲ.【Conclusion】Therefore,influenced by different factors,the moisture content and wood density of woody debris exhibited unique patterns,and decay class and interspecies difference were important factors affecting the variations in the moisture content and wood density.