摘要
森林细根生物量与乔木层胸高断面积关系,以及在高大气N沉降背景下细根对土壤氮的响应程度,目前仍不明确。本研究选择广州市受保护40 a左右的南亚热带常绿阔叶次生林为研究对象,在全市范围内设置了48个森林样地,开展乔木层、灌草层、细根（直径≤2 mm）、土壤C含量和N含量的调查,研究乔木胸高断面积、乔木密度、灌草层生物量、土壤N含量、土壤单位碳的N含量与细根生物量之间的关系,探讨地上植被因子和土壤N对细根生物量的影响。结果表明,（1）土壤表层（0~20 cm）和土壤下层（20~40 cm）细根生物量与乔木层总胸高断面积均不相关,但与胸径30 cm以上乔木的胸高断面积所占比例负相关。（2）表层细根生物量与灌草层生物量不相关,下层细根生物量与灌草层生物量负相关。（3）除了表层细根生物量与相应土层土壤N含量不相关外,下层细根生物量与相应土层土壤N含量,以及表层和下层细根生物量与相应土层单位碳的N含量均负相关。研究表明,对于林木胸径组成差异大的南亚热带常绿阔叶次生林,对细根生物量产生影响的是胸径30 cm以上乔木的胸高断面积所占全部乔木总胸高断面积比例,而不是乔木层总胸高断面积。细根生物量与土壤N含量负相关,表明即使在高大气N沉降背景下,南亚热带常绿阔叶次生林的森林植被仍对土壤N存在响应。
The relationship between fine root biomass and tree basal area at breast height, and how fine roots would respond to soilnitrogen （N） in the forests with high atmospheric N deposition both are still not clear. Therefore, a study on the relationships of fineroot biomass with total tree basal area at breast height, the ratio of basal area for big trees （diameter at breast height, DBH ≥ 30 cm）to total trees, tree density, understory biomass, soil nitrogen concentration, and soil N/C ratio was conducted in lower subtropicalevergreen broad-leaved secondary forests in Guangzhou. Forty-eight forest plots with mostly 1 200 m2 area were set up andinvestigated. These forests, called ecological forests, were protected from commercial use and human disturbance for about 40 years.This study was aim to estimate the effects of the stand vegetation factors and soil N on fine root biomass. Our results showed that： （1）Both of fine root biomass in 0~20 cm （topsoil） and 20~40 cm soil layers （subsoil） were not correlated to total tree basal area at breastheight, but were negatively correlated to the ratio of basal area for big trees to total trees. （2） The correlation between fine rootbiomass and understory biomass was not significant in topsoil, but was negatively significant in subsoil. （3） The correlations betweenfine root biomass in each soil layers and the according soil N concentration or N concentration per unit carbon concentration （N/Cratio） were negatively significant, except that for fine root biomass in topsoil and soil N concentration. These results indicated thatthe ratio of basal area for big trees （DBH ≥ 30 cm） to total trees rather than the total tree basal area affect fine root biomass in thesesecondary forests with large different tree DBH composition. The negative correlations between fine root biomass and soil Nconcentration indicate that forest plants still respond to soil N even in these evergreen broad-leaved forests in lower subtropicalChina with high atmospheric N de
出处
《生态环境学报》
CSCD
北大核心
2016年第2期183-188,共6页
Ecology and Environmental Sciences
基金
广州市林业和园林局重点科技项目"广州市森林碳汇计量与监测研究(2013-2016)"
关键词
细根
乔木层胸高断面积
氮沉降
南亚热带
常绿阔叶林
fine roots
tree basal area at breast height
nitrogen deposition
lower subtropical
evergreen broad-leaved forest
