间伐对侧柏人工林生物量的影响

The Thinning Effects on Biomass of Platycladus orientalis Plantation

利用相对生长法研究了间伐对于徐州市石灰岩山地侧柏人工林总生物量、单株生物量和径级生物量的影响。结果表明:未间伐样地生物量总量为67.64 t/hm2,1次间伐提高了整个林分的生物量,总量提高到了70.11t/hm2,2次间伐林分生物量反而明显减少,减少到了54.19 t/hm2;1次间伐(间伐强度27.7%)和2次间伐(间伐强度44.7%)都提高了树干生物量在林分总生物量中的比例,由53.12%提高到了58.68%和58.69%。1次间伐和2次间伐后,单株侧柏各器官及单株总生物量都比未间伐林地有显著增加,单株生物量由28.78 kg增加到41.24 kg和41.68 kg,树干生物量增长最为显著,由15.29 kg增加到24.20 kg和24.46 kg。未间伐样地,生物量集中在小径级的立木,间伐后生物量集中到了大径级立木。对照样地14 cm和≥16 cm径级的生物量所占比例分别为22.44%和6.57%,1次间伐之后,14 cm和≥16 cm径级的生物量所占比例增加到了26.44%和30.57%,2次间伐后,14 cm和≥16 cm径级的生物量所占比例达到了34.78%和28.94%。

Using the allometric growth model, the effects of thinning on the biomass of Platycladus orientalis plantation （stand, individual and different diameter class ） in the limestone mountain areas of Xuzhou were studied. The results showed that the stand biomass in the control plots （67.64 t/hm^2） was lower than that in the plots with one time thinning （70. 11 t/hm^2） but higher than that in the plots with two times thinning （54.19 t/hm^2）. Both one time thinning （thinning intensity 27.7% ） and two times thinning （ thinning intensity 44.7% ） increased the proportion of the trunks in total biomass of stand, increased from 53.12% to 58.68% and 58.69%. The individual biomass in the plots with thinning was significantly higher than that in the control plots, from 28.78 kg to 41.24 kg and 41.68 kg, respectively, especially for the biomass of trunks, which was increased from 15.29 kg to 24.20 kg and 24.46 kg. In the control plots, the biomass of 14 cm and ≥ 16 cm diameter class trees was only 22.44% and 6.57% of the total stand biomass; however, in the plots with one time thinning, it was increased by 26.44% and 30.57%, respectively. In the plots with two times thinning, the biomass of 14 cm and ≥ 16 cm diameter class trees was reached to 34.78% and 28.94% , respectively.