北京古树土壤主要矿质元素特征及对古树健康响应分析

为了分析北京地区典型古树群内的侧柏土壤常见矿质元素的特征，以地坛、香山、永陵、庆王坟的侧柏古树为研究对象，采用常规统计方法分析不同区域和不同级别土壤矿质元素（钙、镁、锌、铁）特征以及土壤矿质元素含量特征与古树健康之间的关系。不同区域侧柏土壤钙、锌和铁含量存在极显著差异，而镁含量无显著差异。不同古树级别下土壤锌的含量存在显著差异，其余3种矿质元素无显著差异。古树健康等级与矿质元素相关性分析表明，钙、铁对古树健康程度的响应趋势为随古树健康等级的上升，钙含量先增加后减小；镁含量与古树健康等级呈负相关性，镁含量越小，古树健康等级越高；锌含量与古树等级呈正相关。北京地区侧柏古树土壤钙、镁、锌、铁含量较高，均为中等变异；镁含量与古树健康等级呈负相关关系，锌含量为正相关关系，其余2种元素为先正后负的关系。明确土壤矿质元素含量与古树健康等级的关系对古树的维护具有指导意义。

Soil main mineral elements characteristics of ancient trees and the response to tree health in Beijing

The objective of this study was to analyze the mineral elements characteristics of Platycladus orientalis（Linn.） Franco soil in typical ancient trees group in Beijing.Statistical methods were used to analyze the characteristics of Ca,Mg,Zn and Fe of Platycladus orientalis（Linn.） Franco in Ditan,Xiangshan,Yongling and Qingwangfen.Also the relationships between healthy degree and mineral elements were analyzed.Location diversities were dramatically reflected on Ca,Zn and Fe content and no obvious difference on Mg.However,the diversity was not shown among different tree classes.The correlation between tree health and trace elements content indicated that the Ca and Fe content increased first and then decreased with the increase of tree health condition.Mg content was the opposite trend as healthy degree increase,while the Zn content was the same trend with the healthy degree.Ca,Mg,Zn and Fe were relatively high content and shown medium variation.The relationships between health degree and Mg were negative and between health degree and Zn were positive.The rests were found to positive first and negative then.The clear relationship between mineral elements and ancient trees health degree could be instructional for ancient trees maintenance.