不同立地条件下水曲柳人工林生长状况的初步研究

The primary research of growth condition of Fraxinus mandshurica plantation in different site condition

不同立地条件的水曲柳人工幼龄林生长指标的调查结果表明：缓坡造林，8a生胸径最大值为6．0cm，树高最大值为6．5m；轻微水湿地造林，经2次施肥后，12a生时平均胸径、平均枝下高生长量较缓坡造林的8a生水曲柳仅具有微弱生长优势，平均树高、平均冠幅和平均枝下高低于8a生缓坡水曲柳幼龄林；农耕地10a生水曲柳人工幼龄林平均树高为4．50m，为其他立地的150％，最大值为6．8m，胸径最大值为7．3em，单位面积立木蓄积为其他立地的158．3％。水曲柳造林后第四年开始，胸径、树高、材积生长较快，胸径连年生长量由0．65cm增至0．80cm以上；树高生长量在4～6a增长最大，连年生长量达1．00m，平均生长量也持续在0．60m以上；材积平均生长量、连年生长量自第四年开始，增幅较大，第六年连年生长量为第五年的1．92倍。

The investigation result of Fraxinus mandshurica young growth plantation growth index of different site condition showed that the diameter at breast height and tree height maximum of 8 years was 6.0cm and 6.5m with gentle slope affor- estation. The average diameter at breast height and height under branch growth amount of 12 years after twice applying fer- tilizer with slight water wetland afforestation had little growth advantage compared with 8 years Fraxinus mandshurica of gen- tle slope afforestation. The average tree height, crown breadth and height under branch was lower than the Fraxinus mand- shurica young growth of 8 years of gentle slope. The young growth plantation of 10 years Fraxinus mandshurica of farm land whose average tree height was 4.50 m was the 150% of other siteg. The maximum value was 6.8m. The maximum value of diameter at breast height was 7.3 cm. The unit area timber accumulation was 158.3% of other site~. The growth of diame- ter at breast height, tree height and volume of wood was fast at the forth year after afforestation. The current annual incre- ment of diameter at breast height increased from 0. 65 cm to more than 0. 80 cm. The tree height growth amount increased most between 4 and 6 year. The current annual increment was 1.00 m. The average growth amount lasted more than 0.60 m. The average volume of wood and current annual increment increase width was larger from the forth year. The current an- nual increment of the sixth year was 1.92 times as much as the fifth year.