森林水文效应的综合分析

引用森林水文实验站和国家水文基本站网中的森林流域和非森林流域的实测资料,进行同步期的对比分析.对于试验小流域或径流场,总结出林冠截留、树干径流和林地拦蓄的一些统计结果,并归纳得到可供利用的计算公式.对于大面积森林流域,主要从基本水文站网中,森林覆盖率明显不同而其它自然地理条件类似的测站进行对比分析,当干旱指数小于1.2的地区,森林使年径流增加,当干旱指数大于1.2的地区,森林使年径流减少.     

农林生态系统中茎流的水文及生物化学特性研究综述

茎流是大气降水与溶解物在植物茎干上的汇集与运移,它对森林和农业生态系统具有重要的水文学和生态意义。本文总结了前人研究成果,加深了对茎流的理解并找出缺陷与误区,以促进对薄弱环节的研究。探讨了气象条件,季节变化,覆被结构,冠层空间型及植被种别等多个复杂易变因素对茎流量和其化学成分的影响。     

玉米茎流与叶面积、降雨强度之间关系研究

为了探求人工降雨条件下,玉米单位时间产生的茎流量、茎流率与叶面积、雨强的关系,从苗期到抽雄结束共进行了5轮试验,用自制降雨茎流收集筒收集试验产生的茎流,通过调节人工降雨装置达到对雨强进行控制的目的,每轮试验设置了6种不同的降雨强度。结果表明:玉米茎流量与叶面积、降雨强度均呈幂函数关系;玉米茎流率与叶面积呈幂函数关系,与降雨强度无直接关系。应选用紧凑型玉米品种,以适当提高栽植密度,增加冠层覆盖度和叶面积指数,从而增加茎流量,削减降雨能量,减轻土壤侵蚀的发生。     

An In Situ Method to Measure and Map Bark pH

Bark pH is an essential parameter which partly governs the chemistry of the bark as well as its suitability as a microhabitat to a wide range of epiphytic organisms. Bark pH is known to vary with tree species, epiphytic cover, stemflow channelization, and anthropogenic influences. To date, reliable methods to quantify the spatial and temporal dimensions of bark pH have remained elusive. The aim of the present study was to develop and validate an in situ method to measure the surface pH of bark with high spatial resolution. Agar-agar panels, prepared with a pH indicator, were used to quantify and map the spatial variation of bark pH for cacao trees in Indonesia. Fine-scale changes of bark pH were clearly detectable and quantifiable with our bark pH mapping method. Bark pH was found to vary as a function of bark microrelief and the presence of epiphytes. The use of pH reference panels validated the bark pH measurements obtained from our method. The bark pH measurement method developed, described, and validated in this article is inexpensive and straightforward. It has the potential for wide adoption by scientists across disciplines who are interested in bark pH and its effect on life in the cortisphere. Unlike conventional methods to measure bark pH in deionized water or KCl extracts, our method is able to identify fine-scale spatial changes in bark pH that are relevant for the colonization of bark by organisms.