摘要
Background:Stemradialgrowthinforestsisnotuniform.Rather,itischaracterizedbyperiodsofrelativelyfastorslowgrowth,orsometimesnogrowthatall.Thesefluctuationsaregenerallyafunctionofvaryingenvironmentalconditions(e.g.wateravailability)and,importantly,willalsobeassociatedwithadjustmentsinpropertiesinthewoodformed.Standlevelconditionsandforestmanagement,particularlythinningandstanddensitywill,however,alsohaveamajorinfluenceonpatternsofgrowthvariation.Weexplorehowdifferentthinninghistoriesand/orstanddensitiesinfluencethesedynamicsoftreegrowthintheimportantcommercialplantationspeciesPinusradiotaD.Don.Methods:DailystemsizechangewasmeasuredusingelectronicpointdendrometersovertwogrowingseasonsonP.rodiatatreesattwosites,subjectedtodifferentthinningregimes.Timing,ratesandperiodicityofannualgrowthwerecalculatedfromthesedata.Results:Greateroverallcross-seaionalgrowthinthinnedplotswasdrivenmainlybytwodynamics.First,thecessationofseasonalgrowthoccurredatleast3weekslaterinthestandsinwhichthinninghadtakenplace.Therewasnodifferencebetweenthinned/unthinnedstands,however,inthetimingofgrowthonset.Second,withinthelongerseason,treesinthinnedplotshadmoregrowthdays(asmuchas20%more)thanunthinnedplots.Theratesofgrowthondayswhengrowthoccurredwerenotdifferent,however.Inthiscontext,itisnotablethatintreesintheunthinnedplotsexperiencingthemostseverecompetitiontherewerestrongMpulsesMofgrowthfollowingdrought-breakingrainfallevents.Unthinnedplotsathighstanddensitiesalsomaintainedasmaller(butconsistent)zoneofdividingcellsthroughouttheseasonthanthinnedplots.Conclusions:InPinusradiatogrowingunderconditionsasinourstudy,conditionslateinsummer,particularlydrought,haveanimportanteffectonthetimingofcessationofgrowth.Earlyseasontemperatureappearstohavenoeffectin
出版日期
2018年04月14日(中国Betway体育网页登陆平台首次上网日期,不代表论文的发表时间)