五台山华北落叶松人工林生物生产力与营养元素的积累

Increase of Biomass and Accumulation of Nutrient Elements in Larix principis-rupprechtii Plantation

在太行五台山地区，调查华北落叶松人工林林分１６块标准地，并测定了单株平均木各器官生物量及营养元素含量，拟合了华北落叶松林木各器官生物量随年龄变化的ｌｏｇｉｓｔｉｃｓ生长方程。试验表明：华北落叶松立木及林分生物量年平均生长随年龄呈抛物线变化，２４年生时达到高峰，而叶片对干材的净光合同化率１８年生时即达顶峰，约为４００ｇ／ｍ２。１５年生林木各器官主要营养元素总积累量，从大到小顺序为Ｎ、Ｃａ、Ｋ、Ｍｇ、Ｐ，林分每公顷可积累以上五种营养元素的总量是８８８．９１ｋｇ。Ｎ为４０６．８６ｋｇ，其中叶片中Ｎ积累２１４．５６ｋｇ，占总Ｎ积累的５２．７４％；干中Ｎ积累５４．３５ｋｇ，占总Ｎ积累的１３．３６％。１５年生华北落叶松林分，生产１吨干物质即固定Ｎ３．５ｋｇ；而生产１ｍ２木材需固定Ｎ４．６ｋｇ；伐倒１ｍ３木材所消耗的Ｎ仅为０．６１１ｋｇ，占１ｍ３木材需固Ｎ总量的１３．３６％。

sample plots of Larix principis-rupprechtii plantation were investigated inWutaishan Mountain region. Biomass of organs and content of nutrient elements of averagetrees were measured in the sample plots. Regression models of tree biomass and DBH wereselected.Annual biomass increment response was simulated according to the logistics equa-tion. The results were as follows. BiOmass of tree and annual forest increment response isshowed by a parabola,its peak is at the age of 24;the peak of the amount of net photosyn-thesis rate of needle(400g/m2)is at the age of 18.When this larch plantation is of 15-year-old,the order of accumulation of nutrient elements is as follows:the amount of the nutrientelement accumulated(including N、Ca、K、Mg、P)are 888.91 kg/hm2 ,among which N 406. 86 ks/hm2(including 54.35 kg/hm2 in stems and 214.56 kg/hm2 in needles).Besides,thereare N 3.5 kg in 1 ton of dry matter and N 4.6 kg in 1 m3 of wood,but only 0.611 kg of Nwas in 1 m3stem(accounting for 13.36%of the total),the rest of the N was in the branch-es,leaves,barks and roots.