抚育间伐对秦岭南坡锐齿栎天然次生林生长的影响

以秦岭南坡锐齿栎天然次生林为研究对象，探讨间伐对锐齿栎林分生长的影响，以期为秦岭南坡锐齿栎林科学经营提供理论依据。于2012年春季在陕西省宁东林业局沙沟林场，按不同抚育间伐蓄积强度0%（CK）、5%、10%、15%、20%和25%设置锐齿栎次生林试验样地12块，并于2018年10月对所有试验样地进行每木检尺并按径阶打生长锥获取木芯，以分析不同抚育间伐强度下锐齿栎林分胸高断面积和蓄积量变化规律。结果表明:1）间伐能提高锐齿栎林分胸高断面积和蓄积量的生长，间伐强度5%样地的林分胸高断面积和蓄积量年平均增长量（1.31 m²·hm^-2和8.84 m³·hm^-2）、总增长量（9.14 m²·hm^-2和61.88 m³·hm^-2）、年平均增长率（6.80%和7.89%）和总增长率（58.40%和70.16%）最高，且均与CK呈显著差异（P<0.05)。2）间伐强度5%和10%样地林分蓄积量分别在间伐后第4年和第7年达到未间伐样地的林分蓄积量。3）间伐强度5%~20%锐齿栎林分胸高断面积和蓄积量的连年生长量、平均生长量均>CK，其中5%样地林分胸高断面积和蓄积连年生长量在间伐后增长最快。因此，抚育间伐有利于锐齿栎林分胸高断面积和蓄积量的生长，其中5%间伐强度最为有利，该强度下林分蓄积量可以在较短年限达到并超过未间伐样地的蓄积量。

Effects of Thinning on the Growth of Quercus aliena var.acuteserrata Natural Secondary Forest on the Southern Slope of Qinling Mountains

The effects of different thinning intensities on the growth of Quercus aliena var.acuteserrata natural secondary forest on the southern slope of the Qinling mountains were studied to provide a theoretical basis for the scientific management of the forest.In the spring of 2012,12 sample plots of Q.aliena var.acuteserrata natural secondary forest were set up in Shagou Forest Farm of Ningdong Forestry Bureau in Shaanxi Province with different thinning intensities,i.e.,0%(control),5%,10%,15%,20%and 25%.In October 2018,tally stem analysis of all the trees in the sample plots was carried out.Increment cores of the trees were obtained according to the diameter class,so as to analyze the basal area at breast height(BABH)and stand volume(SV)changes of the forest under different tending and thinning intensities.The results showed that 1)thinning improved the growth of BABH and SV.Under the thinning intensity of 15%,the annual increases,the total increments,the annual growth rates,and total growth rates of BABH and SV were 1.31 m^2·hm^-2 and 8.84 m^3·hm^-2,9.14 m^2·hm^-2 and 61.88 m^3·hm^-2,6.80%and 7.89%,and 58.40%and 70.16%,respectively,which were the highest among those of other thinning intensities,and the differences in BABH and SV between 15%and the control were significant(P<0.05).2)The SV of sample plots with 5%and 10%thinning intensities reached the same amounts with unthinned sample plots in the 4th and 7th year after thinning.3)The current annual increment and mean annual increment of BABH and SV of 5%-20%thinning intensity sample plots were all higher than the control,among which the current annual increments of BABH and SV of 5%thinning intensity sample plots were the highest after thinning.Therefore,thinning was beneficial to the growth of BABH and SVof Q.aliena var.acuteserrata forest,and the most favorable thinning intensity was 5%,under this intensity,the SV could reach and exceeded the unthinned sample plots in a short period of time.