次生阔叶林改建为食用菌原料林后的群落恢复和林分生长

选择林相较好的12年生天然次生阔叶林,通过择伐更新和皆伐人促更新两种经营方式定向培育食用菌原料 林。结果表明:择伐经营的经济效益较高,且有利于群落的快速恢复,经过7a的封育,林分蓄积量已达到择伐前当 年的水平。皆伐人促更新获得的食用菌材虽较择伐利用高出40％左右,但因经营强度过大,保留的幼树受损严重 而不利于伐后林木的生长与恢复,封育期内蓄积增长量分别为择伐更新和对照未经营区的64.7％和73.4％。动态 监测结果显示,采用择伐和皆伐人促更新措施后,群落恢复较快。疏伐后因透光度的急剧增加,阳性和中性树种大 量侵入,地面芽植物和1年生植物的比例增高。到第7年时,高位芽植物的比例已接近未经营区的状态,乔、灌、草 各层的物种多样性指数高于未经营的天然阔叶林,物种均匀度则与其相近。研究还发现,两种更新经营方式对土壤 养分的损失较小,经过7a的恢复,林地土壤肥力已基本达到原有天然林水平。

Community Recovery and Stand Growth after Transforming the Secondary Broadleaved Forest into the Edible Fungi Raw Material Forest

The research found that the economic benefit was relatively high for the selection cutting which was advantageous to the rapid community recovery. The stand stocking already reached the level before the selection cutting with 7-years forest conservation. Although the amount of edible fungi timber gained was great for the clean cutting regeneration, the reserved young trees were damaged heavily, which was disadvantage to the growth and recovery of forest after felling. The increase amount of stand stocking during the forest conservation period was 64. 7% and 73. 4% of that with the selection cutting regeneration and the control in the area without management. The dynamic monitor result showed that the community recovery was relatively rapid after adopting the measures of selection cutting and the clean cutting regeneration with artificial promotion. The ground bud plant and 1 -year-old plant proportions increased because of the transmittance' s increasing sharply and the mass intrusions of heliophilous and indeteminate tree species after the thinning. In the 7th year, the phaenerophyte proportion was already close to that of the area without management. The species diversity indexes of different layers of arbor, brush and grass were higher than that of natural broadleaved forest without management, but the species homogeneous degrees of the different layers were close to the degree of natural broadleaved forest. The study also found that the soil nutrient loss was small for the two reproduction management modes. The forest land soil fertility already reached the former natural forest land soil fertility level through the 7-year' s recovery.