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MODELS FOR CROWN STRUCTURE OF LARCH PLANTATION 总被引:1,自引:0,他引:1
INTRODUCTIONToreflecttree'sgrowthactivityandcompetitioneffectsoftree'sdevelopment,someofcrownvariablescanbeusedtode-velopcompetitionindexes(Mitchelll975,BigingandWensell99O,BigingandDobbertin,l992).Thecrownsizedirectlyinfluencestree'sassimilationanditisoneofthebasicvariableforpredictingincrementoftree.TherefOre,inmanygrowthandyieldmod-els,treecrowndimensionsareoftenusedasanimportantcomponent.Crownvariablesintroducedingrowthmodelsasameanstoimprovethepredictiveabilityandaccuracyoftreeors… 相似文献
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1饲喂
做好初产日龄的控制。采用性成熟期断食法,对推迟育成鸡初产日龄,改善产蛋性能,对鸡群高产稳产都有很好的效果。具体做法是从鸡群产蛋率达到5%开始,断食8~10天。 相似文献
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