Growth at the microscale:long term thinning effects on patterns and timing of intra-annual stem increment in radiata pine

作     者：David M.Drew Geoffrey M.Downes 

作者机构：Department of Forest and Wood ScienceStellenbosch UniversityPrivate Bag X1Matieland 7800South Africa Forest Quality Pty LtdPO Box 293 HuonvilleTASAustralia. 

出 版 物：《Forest Ecosystems》 (森林生态系统（英文版）)

年 卷 期：2018年第5卷第4期

页      面：438-450页

核心收录：

学科分类：0710[理学-生物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 0907[农学-林学] 0829[工学-林业工程] 09[农学] 0901[农学-作物学] 0833[工学-城乡规划学] 0713[理学-生态学] 0834[工学-风景园林学（可授工学、农学学位）] 

基　　金：funded in large part by a grant(PNC 196-1011)from Forest and Wood Products Australia(FWPA)and funding and in-kind support from HVP FSA and CSIRO 

主　　题：Monterey pine Dendrometer Intra-annual growth Drought Thinning 

摘      要：Background: Stem radial growth in forests is not uniform. Rather, it is characterized by periods of relatively fast or slow growth, or sometimes no growth at all. These fluctuations are generally a function of varying environmental conditions(e.g. water availability) and, importantly, will also be associated with adjustments in proprties in the wood formed. Stand level conditions and forest management, particularly thinning and stand density will, thowever, also have a major influence on patterns of growth variation. We explore how different thinning histories and/or stand densities influence these dynamics of tree growth in the important commercial plantation species Pinus radiata D. ***: Daily stem size change was measured using electronic point dendrometers over two growing seasons on P. radiata trees at two sites, subjected to different thinning regimes. Timing, rates and periodicity of annual growth were calculated from these ***: Greater overall cross-sectional growth in thinned plots was driven mainly by two dynamics. First, the cessation of seasonal growth occurred at least 3 weeks later in the stands in which thinning had taken place. There was no difference between thinned/unthinned stands, however, in the timing of growth onset. Second, within the longer season, trees in thinned plots had more growth days(as much as 20% more) than unthinned plots. The rates of growth on days when growth occurred were not different, however. In this context, it is notable that in trees in the unthinned plots experiencing the most severe competition there were strong pulses of growth following drought-breaking rainfall events. Unthinned plots at high stand densities also maintained a smaller(but consistent) zone of dividing cells throughout the season than thinned ***: In Pinus radiata growing under conditions as in our study, conditions late in summer, particularly drought, have an important effect on the timing of cessation of growth. Earl