马尾松天然次生林近自然经营研究

Research on close-to-nature management of natural secondary Pinus massoniana forest

对湖南慈利县乔木层22年生马尾松天然次生林进行近自然经营,对目标树周围干扰树采用不同强度的处理,6年生长数据分析和根据NPV及现金流量表分析发现:(1)不同强度伐除干扰树对整体林分和目标树的树高生长增量影响极低,但对胸径生长增量影响较大。高强度伐除干扰树能提高整体林分的平均胸径生长增量,6年可达到3.6 cm;(2)经过人为干扰的目标树生长增量远超于未做干扰的其它树,一代和二代目标树平均胸径生长增量均高于其它树,达到3.0 cm和2.6 cm,尤其是阔叶树种人为干扰后生长迅速,最快的是樟树,6年平均胸径生长增量达到6.0 cm;(3)高强度的伐除干扰树对目标树经营效果最好,目标树生长增量远超其它处理强度,尤其是二代目标树6年平均胸径生长增量达到了4.1 cm,一代目标树和其它树也分别达到3.5 cm和2.9 cm;(4)以1 hm^2为计算单位,在100年限内人工林经营3次周期累计净现值为26 459元,马尾松目标树经营为37 158元,目标树经营超出人工林经营10 699元。随着经营年限增加目标树经营将进一步拉大与人工林经营的经济收益。

Close-to-nature management on the arbor layer of the 22 years old natural secondary Pinus massoniana forest in Hunan Cili was conducted,and the interference trees around the target tree were treated with different intensity. The 6 years growth data analysis and the analysis of NPV and cash flow table showed that, different intensity removal interference trees had a very low influence on the height growth increment of the whole stand and the target tree. But it had great influence on the growth increment of DBH. High intensity removal interference tree could increase the growth increment of average DBH,and it could reach 3. 6 cm after 6 a. The growth increment of target tree was far more than that of other trees by the human disturbance. The increment of average DBH growth of the firstand two generation target trees was higher than that of other trees to 3. 0 cm and 2. 6 cm,especially broad-leaved tree species. The growth increment of average DBH of Cinnamomum bodinieri reached 6. 0 cm after 6 a. The high intensity removal interference tree had the best management effect on the target tree,the growth increment of the target tree was far beyond the other management strength, especially the average DBH growth increment of the second generation target tree reached 4. 1 cm after 6 a,the first generation target tree and other tree also reached 3. 5 cm and 2. 9 cm. With a hectare as the calculating unit,plantation operations within the fixed number of 100 years of three cycle cumulative NPV value is 26 459 RMB,natural secondary Pinus massoniana forest tree management target of 37158 RMB,target tree management beyond plantation 10699 RMB. With the increase of management years,the management of target tree will further widen the economic benefits more than plantation management.