摘要
介绍质量平衡法的理论、估测方法及其应用,并对其进行评价。质量平衡理论认为:一段树干组织产生的CO2,应该是CO2通量的总和,包括通过树皮向外扩散的CO2释放通量、该段树干液流中的CO2运输通量(流入和流出液流的CO2浓度之差)及液流中的CO2储存通量(液流中CO2浓度在时间上的变化量)。应用质量平衡法测定树干呼吸的关键是要估测树干内部的CO2通量,即液流中CO2的储存、运输和扩散。对于液流中CO2的估测主要有2种方法:1)用仪器直接测定木质部液流中的CO2浓度;2)通过测定树干液流停止流动或相对很低时(夜间)树干的CO2释放通量与液流流动时(白天)树干CO2释放通量的差值,间接估测木质部液流中CO2浓度。质量平衡方法提供了一个更为精确地估测木本组织呼吸的方法,其结果更为合理。
Stem respiration is an important part of the carbon balance research of forest community and ecosystem. A new method to estimate stem respiration, demonstrated in the United States, namely mass balance approach, was introduced in this paper, including the theory, measurement methods and some study cases. Mass balance theory considers that the CO2 production of a segment of stem tissue should be sum of CO2 fluxes, including CO2 leaving the segment by diffusion through bark （efflux to atmosphere）, CO2 entering and leaving the segment in flowing sap （influx and efflux transported） and the CO2 increased or decreased in mean sap concentration over time （storage flux）. The key item of mass balance approach is to determine the CO2 flux of sap flow （ storage and transport flux and efflux）. There are two methods to estimate CO2 concentration in sap flow by mass balance approach： 1 ） Directly measurement using instruments; 2） Indirectly estimation by calculating the efflux deference between the sap flow ceased or at vary low velocity （ night time） and the sap is flowing （ day time）. Mass balance approach provides a more accurate method to evaluate stem respiration and makes the results more reasonable.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2007年第10期106-111,共6页
Scientia Silvae Sinicae
基金
国家自然科学基金(30471372)资助
