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旺盛的蒸腾是竹子迅速生长的重要代谢保障,对林区生态系统水循环和水量平衡发挥关键作用,如何准确估测竹林的蒸腾耗水是迫切需要解决的方法难题。目前研究树木水分生理和森林水文广泛采用的热消散液流测定方法(TDP)却少有在竹林中应用,而仅有的几项研究报道由于缺乏严谨的实验验证,结果误差较大而缺少说服力。作者认为,竹壁结构异质性和竹竿中央空腔造成热量的不均匀分布是基于热通量交换的液流测定系统测量竹子蒸腾不准确的主要原因,提出以自行设计的注水变压液流特性测定法和传统的整树容器称重法,验证热消散液流测定系统估测竹子水分利用的适用性。本文还结合竹子的种群结构和无次生生长的特点,提出竹株借助相互连接的地下茎进行水分再分配,异株补偿水力限制,蒸腾主要受年龄而不是竹形大小影响的观点,建议通过分析竹子蒸腾的年龄效应,研究不同种植密度竹林水分利用的变化规律,为竹林生产和集水区水源管理提供有效的林型设计和措施。
Exuberant transpiration is an important metabolic guarantee for the rapid growth of bamboo, and plays a key role in water cycle and water balance in forest ecosystems. How to accurately estimate transpiration water consumption of bamboo forest is an urgent problem to be solved. At present, there are few applications of TDP in the study of water physiology and forest hydrology. However, only a few studies have reported that due to the lack of rigorous experimental verification, the results of errors are large and lack of persuasion force. The author believes that the structural heterogeneity of bamboo wall and the uneven distribution of heat caused by the central hollow of bamboo stem are the main reasons for the inaccurate measurement of bamboo transpiration by the flow measurement system of heat flux exchange. Characterization and traditional whole-tree container weighing method to verify the applicability of heat dissipation flow measurement system to estimate bamboo water use. Based on the characteristics of population structure and secondary growth of bamboo, this paper proposed the idea that bamboo should be redistributed with underground stems connected to each other, hydraulic compensation of different plants, and transpiration should be influenced mainly by age rather than bamboo size. The age effect of bamboo transpiration, the study on the variation of water use efficiency in different plantation density bamboo forests, providing effective forest design and measures for water management in bamboo production and catchments.