珍稀濒危植物珙桐的生存与人为活动的关系

近年来，由于人类活动的加剧，区域开发项目的增多，致使珍稀濒危树种珙桐的天然分布面积和天然种群数量急剧下降，现天然分布种群已濒临灭绝。为此，本文系统分析了珙桐在不同地质阶段和不同历史阶段的地理分布状况，探讨了促使其地理分布及种数数理动态变化的主要原因，通过大面积的野外调查和查阅资料，提出了珙桐的保护措施。

Relationship between human activities and survival of rare and endangered species Davidia involucrata

In recent years,the increasing intensity of human activities and the increase of regional developing items led to a sharp decrease of natural distributed area and natural population number of rare and endangered species Davidia involucrata, and now, its natural distributed population is on the point of extinction.This paper analyzed the geographic distribution situation of Davidia involucrata in different geologic and historical periods,and discussed the major reasons for forming the geographic distribution and dynamic changes of population.Through many field investigations and references,some protecting measures were presented.