The more the water shortage , the thicker the dried layer ( 4 )嚴(yán)重土壤干層使天然下種更新不良。
Through the stand investigation by setting up the sample site , the investigation results showed that the average dbh of 15 - year - old alniqhtllm fortunei planted under nature was 60 % larger than that of 17 - year - old pinus massoniana plantation under the same condition , the average tree height of the above was 38 % larger than that of the latter , the average single - tree volume of the above was 3 . 2 times higher than that of the latter , the above showed the absolute dominance in stands 摘要設(shè)立標(biāo)準(zhǔn)地進(jìn)行林分調(diào)查,在標(biāo)準(zhǔn)地中選取擬赤楊標(biāo)準(zhǔn)木進(jìn)行樹干解析,采用生長對(duì)比方式分析擬赤楊在馬尾松人工林中的生長情況,調(diào)查結(jié)果表明,在同一環(huán)境條件下, 15年生天然下種的擬赤楊比17年生馬尾松人工林平均胸徑大60 % ,平均樹高高38 % ,平均單株材積大3 . 2倍,在林分中表現(xiàn)出絕對(duì)優(yōu)勢(shì)。