四川盆地丘陵区柏木防护林防护成熟研究

应用典型调查抽样调查对四川盆地丘陵区柏木防护林成熟进行了研究。根据样地调查和树干解析资料,建立柏木林胸径、树高、生物量、及冠幅生长的数学模型,通过数学模型计算出不同立地条件下柏木林的初始防护成熟龄;以林分平均木生物量指标为依据,确定不同立地条件下柏木林的最大防护成熟龄;根据初始防护成熟龄和最大防护成熟龄确定防护成熟期、更新期及合理的更新年龄。3种生长类型Ⅰ、Ⅱ、Ⅲ初始防护成熟龄分别为:13.4a、15.4 a、18.2 a;最大防护成熟龄分别为:97 a,77 a,53 a;防护成熟期分别为:13.4～97 a,15.4 a～77 a,18.2 a～53a;更新期分别为:49 a～97 a、34 a～77 a、23 a～53 a;合理的更新年龄分别为:49 a、77 a、53 a。通过对比研究得出,立地条件越好则柏木林的初始防护成熟期来得越早,最大防护成熟期来得越晚,相应的防护成熟期越长,更有利于发挥林分的防护效益,反之,则防护效益越短。

A Study of Maturity of Protection Forests in Hilly Areas of the Sichuan Basin

Through the typical survey and positioning observation,a research was conducted into the maturity of protection forests in hilly areas of the Sichuan Basin.The mathematical models of diameter,height,biomass and canopy of cypress forests were established by means of the survey of sample plots and stem analysis;Then,the determinations were made on initial protective mature age,maximal protective mature age,protective mature period,regeneration period and rational regeneration age of cypress protection forests.The initial protective mature age of cypress protection forests was 13.4 years,15.4 years and 18.2 years for good,moderate and poor site quality respectively;the maximal protective mature age was 97 years,77 years and 53 years;and the protective mature period was 13.4 years~97 years,15.4 years~77 years and 18.2 years~53 years;the regeneration period was 49 years~97 years,34 years~77 years and 23 years~53 years;and the rational regeneration age was 49 years,77 years and 53 years for good,moderate and poor site quality respectively.It was indicated that the initial protective age came earlier in the good site than that in the poor site,but the maximal protective mature age came up later,and the forests had a longer mature period.