小兴安岭红松活立木树干腐朽与立地土壤理化特性的关系

Correlations between standing trees trunk decay degree and soil physical-chemical properties in Korean pine-broadleaved mixed forest in Xiao Xing'an Mountains of Northeast China

活立木腐朽造成大量木材资源损失.研究活立木腐朽与立地生境之间的关系,对于科学合理地营林管理、减少木材资源损失有着积极的指导意义.2011年5月,使用阻抗仪对小兴安岭林区红松阔叶混交林中15株成熟龄的红松活立木树干根部腐朽状况及胸径进行了检测,同时分别在活立木根部、坡上距根部5 m和坡下距根部5 m处采集土样,测定土壤的含水率、容重、总孔隙度、pH值和有机质含量,并建立了活立木树干根部腐朽程度与其胸径和各样点土壤理化指标的回归方程.结果表明:成熟龄红松活立木树干根部腐朽程度与根部土壤5项理化指标有较强的相关性(R=0.687),且与土壤含水率呈显著正相关(R=0.507),而与坡上和坡下距根部5 m土壤各理化特性指标的相关性不显著.土壤含水率降至18.4%以下时将有助于降低树干根部的腐朽程度.成熟龄红松活立木树干根部腐朽程度与树龄的相关性不显著.

Standing trees decay often causes vast loss of timber resources. To investigate the correlations between the standing trees decay and the site conditions is of importance to scientifically and reasonably manage forests and to decrease wood resources loss. By using Resistograph and meter ruler, a measurement was made on the decay degree of the trunk near root and the diameter at breast height （DBH） of 15 mature Korean pine standing trees in a Korean pine-broadleaved mixed forest in Xiao Xing＇ an Mountains in May, 2011. In the meantime, soil samples were collected from the root zones of standing trees and the upslope and downslope 5 meters away from the trunks, respectively. Five physical-chemical properties including moisture content, bulk density, total porosity, pH value, and organic matter content of the soil samples were tested. The regression equations concerning the trunk decay degree of the standing trees, their DBH, and the 5 soil properties were established. The results showed that the trunk decay degree of the mature Korean pine standing trees had higher correlations with the bulk density, total porosity, pH value, and organic matter content （R = 0.687）, and significant positive correlation with the moisture content （R=0. 507） of the soils at the root zones of standing trees, but less correlation with the 5 properties of the soils at both upslope and downslope 5 meters away from the trunks. The trunk decay degree was decreased when the soil moisture content was below 18.4%. No significant correlation was observed between the trunk decay degree of mature Korean pine standing trees and the tree age.