敖汉旗小流域主要树种生长过程的研究

The Growth Process of Main Tree Species in Small Watershed of Aohan

在内蒙古赤峰市敖汉旗小流域选择小叶杨、白榆、油松为研究对象,采用样地法和标准木树干解析木法,对标准地内林木进行每木检尺,同时对标准木树干解析,从而对流域内3种人工造林树种进行树高、胸径以及材积生长过程分析.结果表明：立地条件对不同人工林都存在明显的生长抑制作用.（1）小叶杨在种植19年后,树高、胸径、材积量生长均出现下降或减缓;从材积生长来看,第5～ 19年时为小叶杨的速生期;（2）白榆在种植后9 ～ 10年间树高和胸径生长速度开始降低,树高连年生长量与平均生长量相交于10年.材积量的快速积累可达22年;（3）油松在种植后14～19年开始出现树高和胸径生长降低现象,种植后19年是油松生长的转折期,应在此时实施疏伐调整.从材积生长来看,第7～20年时为油松的速生期.

Taking Populus simonii, Ulmus pumila and Pinus tabulaeformis chosen from the small watershed in Ao- han, Inner Mongolia as the studying object, by use of the sample plot method and standard wood stem analysis method, the trees in standard plot have been made each wood gauging, and the stem analysis has been made to the standard wood. And the growing process of tree height, DBH and volume of three tree species for artificial afforesta- tion have been analyzed in watershed. The results show that the site conditions can restrain the growth of different planations obviously. （1） For Populus simonii, after planting for 19 years, the growth of tree height, DBH and vol- ume decrease and slow down. The fifth year to the 19th year is the fast -growing period for Populus simonii. （2） For Ulmus pumila, after planting for 9 - 10 years, the growth of tree height and DBH decrease, the current annual increment and mean annual increment of tree height meet in 10 years. And the rapid accumulation of volume can be up to 22 years. （3） For Pinus tabulaeformis, after planting for 14 - 19 years, the growth of tree height and DBH decrease. After planting for 19 years, the thinning should be done. From the growth of volume, the rapid growing stage for Pinus tabulaeformis is from the 7th year to the 20th year.