黄栌根系结构与个体健康程度的关系

以北京延庆八达岭国家森林公园红叶岭景区阳坡黄栌纯林为调查对象，采用人工挖掘法，研究黄栌根系结构与个体健康程度的关系。结果表明:健康程度、树木大小及其交互作用对黄栌根系结构影响显著；健康黄栌根系结构各指标显著高于中等健康黄栌和不健康黄栌，不健康黄栌0.0~0.1 mm、2.0~5.0 mm、>5.0 mm直径范围内的根系显著低于健康黄栌；大树的比根长、比根表面积、比根体积、根尖数量、分枝数量、连接数量和平均连接长度分别比小树低71.8%、54.6%、35.4%、59.3%、26.3%、30.1%和6.9%，在0.0~0.2 mm范围内，小树根系结构各指标及其所占比例显著高于大树根系，而在>1.0 mm范围内则显著低于大树根系；黄栌根系的发育能力随着树木老化和健康程度的降低而减弱，不健康黄栌大树的根系发育能力最弱。因此，根系发育程度和结构变化可较好地反映北京地区黄栌健康程度，恢复根系活力可能成为恢复老龄黄栌生命力的重要措施。

Relationship between Root Structure and Health Level of Cotius coggygria Trees

Cotinus coggygria trees occurring in pure planted stand in the sunny slope of red-leaf hill scenic area were investigated in Badaling National Forest Park situated in Yanqing County in Beijing.The relationship between root structure and health level of C.coggygria trees was studied by using the artificial digging method.The results indicated that the root structure was significantly affected by the level of tree health,tree size and their interactions.Root structure parameters of healthy trees were remarkably higher than those of middle level healthy and unhealthy trees.Roots of unhealthy trees with diameters ranges of 0.0~0.1 mm,2.0~5.0 mm,and >5.0 mm exhibited obvious declines compared with those of healthy trees.The specific root length,specific root surface area,specific root volume,root tips,root forks,root links and average root link length of big trees were lower than small trees by 71.8%,54.6%,35.4%,59.3%,26.3%,30.1% and 6.9%,respectively.The root parameters and their proportions of small trees were remarkably higher than big trees at the diameter range of 0.0~0.2 mm,while the root parameters and their proportions of big trees were significantly higher than small trees at the diameter of >1.0 mm.The root development capacity and health level decreased gradually with tree growth.The root development of the big trees with low health level was the poorest.Therefore,the variation of root development and structure of C.coggygria in Beijing could well reflect the health level of the trees,and root activity recovering may be a major measure to restore the vitality of aging C.coggygria.