側(cè)柏人工幼齡林單木生長的競爭效應(yīng)模型1)

馬士友 楊華 張恒 尚旭陽 張詠 張永福

(省部共建森林培育與保護(hù)教育部重點實驗室(北京林業(yè)大學(xué))，北京，100083) (北京市十三陵林場)

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側(cè)柏人工幼齡林單木生長的競爭效應(yīng)模型1)

馬士友 楊華 張恒 尚旭陽 張詠 張永福

(省部共建森林培育與保護(hù)教育部重點實驗室(北京林業(yè)大學(xué))，北京，100083) (北京市十三陵林場)

為量化采伐對林木生長的影響，以北京郊區(qū)側(cè)柏人工幼齡林為研究對象，以競爭指數(shù)、采伐指數(shù)作為自變量，伐后5 a胸高斷面積生長量為因變量，構(gòu)建側(cè)柏人工幼齡林競爭效應(yīng)模型，采用判斷系數(shù)(R2)、剩余標(biāo)準(zhǔn)差(RMSE)、赤池信息準(zhǔn)則(AIC)對模型進(jìn)行評價。結(jié)果表明：斷面積比競爭指數(shù)(CI2)、采伐指數(shù)(RI2)優(yōu)于其余4種指數(shù)；得到了以5種競爭指數(shù)和采伐指數(shù)為自變量的競爭效應(yīng)模型，根據(jù)模型R2、RMSE、AIC值，推斷出側(cè)柏人工幼齡林的最佳競爭范圍的半徑為4 m；以CI2r4、RI2r4為自變量的模型比只有CI2r4的模型R2提高了33.8%，說明采伐對側(cè)柏單木生長的影響顯著。

側(cè)柏人工幼齡林；競爭范圍；采伐；競爭指數(shù)；采伐指數(shù)

Platycladusorientalisyoung plantation were selected to quantify the cutting influence on tree growth in Beijing suburb. We used the competition index, cutting index and 5-year basal area growth after cutting as dependent variables to constructP.orientalisyoung plantation competition effect model. The model was evaluated by the judgment coefficient (R2), the residual standard deviation (RMSE) and the Akaike Information Criterion (AIC). The basal area ratio competition indexCI2, cutting indexRI2were superior to the other four indexes. Then the competition effect model with five kinds of competition index and cutting index were got as independent variables. According to theR2,RMSE,AIC, the best competition range of semi diameter ofP.orientalisyoung plantation was 4 m. TheR2of the model, which usedCI2r4andRI2r4as the independent variables, was increased by 33.8%, indicating that cutting has a significant influence on individual tree growth.

競爭是生物間相互作用的一個重要方面，是指2個或多個生物體在對同一環(huán)境資源和能量的爭奪中所發(fā)生的相互作用。由于林分內(nèi)存在大小不同的樹木，它們所占據(jù)的生長空間不同，各自承受著不同的競爭壓力，這種壓力必然導(dǎo)致林木個體生長的差異性。為描述這種單木的生長動態(tài)，引入了單木競爭指數(shù)[1]，為了更好的描述不同林分的競爭狀態(tài)，建立了各種各樣的競爭指數(shù)模型[2-12]。

對象木最佳競爭范圍指對某一株對象木而言，周圍鄰近木能夠?qū)ζ洚a(chǎn)生影響的空間范圍。……