Effects of Pruning to Promote Trunk Extension on Annual Growth Rhythm of Paulownia

(整期优先)网络出版时间:2004-01-11
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Thispaperaimstoconfirmtheoptimalpruningintensitytopromotepaulowniagrowth.Annualdynamicof8growthindicatorsforpruningofthree-year-oldPaulowniatopromotetnmkextensionweresimulatedunder7treatments.TheresultsshowedthatannualgrowthprocesscouldbemodeledreliablybyRichards'function.Eightgrowthparametersweredevelopedincludingfast-growingpoint(t0),initialpointoffast-growingperiod(tl),finalpointoffast-growingperiod(t2),fast-growingperiod(t),growthperiod(Dg),maximumdayincrement(AGRmax),maximumannualincrement(A).Effectsofpruningtopromotetrunkextensionongrowthparameterswereanalyzed.Paulowniaremaining3-6lowerbranchesafterpruninghadrelativelylongerfast-growingperiod(t),growthperiod(Dg),higheraveragedayincrement(Am),maximumdayincrement(AGRmax)andmaximumannualincrement(A).Therefore,lowerdiametergrowthoforiginaltrunkdidnotdecreasesignificantly,andupperdiametergrowthincreasedtosomeextent,Heightanddiametergrowthofgraftingtrunk,andformratioofgraftingtrunkwererelativelyhigher.Totalstockvolumeincrementwasimprovedsignificantlyundertheconditionthatstockvolumeincrementoforiginaltrunkdidnotdecrease.