CAJ | 학술논문

树干液流在微时空尺度上具有较大的变异性,尺度扩展过程中又极易引起误差,而有些环境因子则是在较大空间尺度上发生变化,容易降低液流密度研究结果的可靠性.引入单位面积液流日累积量(Q_a)和液流密度峰值(J_(smax))这2个参数,根据树高和胸径划分不同优势度,研究木荷树干液流时空动态特征及与环境因子的关系,探讨液流密度研究更合理的方法.结果表明:2007年9月到2008年4月木荷优势木、中等木和劣势木液流日进程均呈现单峰格型,根据树高划分优势度等级的木荷中等木平均液流密度要略大于优势木,劣势木的平均液流密度远远低于优势木和中等木;而根据胸径划分优势度等级的木荷优势木液流大于中等木,中等木液流大于劣势木;光合有效辐射是影响优势木和中等木液流密度的主要环境因子,劣势木液流密度主要受气温影响;在干旱胁迫下,土壤含水量对优势木和中等木液流密度瞬时变化的影响比劣势木显著;总体而言,土壤湿度对液流瞬时值影响不大,但显著影响大时间尺度上优势木液流累积量的变化.按树高划分的木荷等级对环境因子的响应更敏感,而按胸径划分的木荷等级显示树形因子对液流的影响不可忽略.根据研究的需求不同,按树高或胸径分级各有优势.
수간액류재미시공척도상구유교대적변이성,척도확전과정중우겁역인기오차,이유사배경인자칙시재교대공간척도상발생변화,용역강저액류밀도연구결과적가고성.인입단위면적액류일루적량(Q_a)화액류밀도봉치(J_(smax))저2개삼수,근거수고화흉경화분불동우세도,연구목하수간액류시공동태특정급여배경인자적관계,탐토액류밀도연구경합리적방법.결과표명:2007년9월도2008년4월목하우세목、중등목화열세목액류일진정균정현단봉격형,근거수고화분우세도등급적목하중등목평균액류밀도요략대우우세목,열세목적평균액류밀도원원저우우세목화중등목;이근거흉경화분우세도등급적목하우세목액류대우중등목,중등목액류대우열세목;광합유효복사시영향우세목화중등목액류밀도적주요배경인자,열세목액류밀도주요수기온영향;재간한협박하,토양함수량대우세목화중등목액류밀도순시변화적영향비열세목현저;총체이언,토양습도대액류순시치영향불대,단현저영향대시간척도상우세목액류루적량적변화.안수고화분적목하등급대배경인자적향응경민감,이안흉경화분적목하등급현시수형인자대액류적영향불가홀략.근거연구적수구불동,안수고혹흉경분급각유우세.
A Granier TDP method was applied to continuously monitor sap flow of Schima superba which is native tree species in South China and data of the changes of environmental factors was synchronously collected to explore dynamic characteristic of trunk sap flux density at different temporal scales and its relation with different dominance and environment factors.The results showed that the daily pattern of sap flux density of dominant,middle and depressed woods exhibited a single-peak curve.The maximum sap flux density of middle wood was slightly higher than that of dominant wood,but the depressed wood was far below those of middle and dominant.Photosynthetically active radiation (PAR) was major factor influencing trunk sap flux density of dominant and middle woods,while air temperature (TA) influenced mainly the depressed wood under the drought stress.Soil moisture (SM) did not apparently influence instantaneous sap flux density,but daily accumulated amount of flux in dominant woods.