近自然森林经营在辽东山区次生林恢复中的应用效果评价

Assessment on Close-to-Nature Forest Management on Secondary Forests in Eastern Mountainous Region of Liaoning

为了改造辽东山区存在的一定面积的低质、低效天然次生林,以1973年辽东山区20年生杨桦林为研究对象,采用3种近自然经营措施(B、C、D)及1种皆伐改造措施(A),研究40a后的改造效果。结果表明:由于采取不同的改造措施,2011年B区红松(Pinus koraiensis)平均胸径略低于红松纯林,但可以同时获得大径级阔叶材,效果最好。2011年各试验区林分总蓄积量存在较大的差异,B区林分总蓄积量最高,为315.470 0 m3.hm-2,比A区提高了14.45%,D区最少。在3种近自然森林经营方式下,林分中白桦(Betula platyphylla)和山杨(Populusdavidiana)逐年减少,刺楸(Kalopanax septemlobus(Thunb.)Koidz.)、水曲柳(Fraxinus mandshurica)、核桃楸(Jug-lans mandshurica)和蒙古栎(Quercus mongolica)等珍贵阔叶树种逐年增多。林分现在已经演替为针阔混交林。与A区相比,B区、C区和D区土壤理化性质均有不同程度的改善。可见,对次生林进行抚育改造冠下"见缝插针"引进红松,并适时进行抚育间伐(B区),林分总收获量高于红松纯林(A区),并且土壤质量有所改善,效果最好。对次生林进行皆伐改造后营造红松纯林,最后一次幼林抚育保留有培育前途的萌生阔叶幼树(D区),虽然林分总蓄积量低于红松纯林,但林分结构和土壤质量有所改善。综合考虑,4种改造方法中B效果最好,C次之,A最差。试验结果对辽东山区的低质、低效天然次生林的改造具有一定的借鉴意义。

A survey was conducted to study the transformations of 20-year-old natural secondary poplar-birch forests in eastern mountainous region of Liaoning province. Three close-to-nature forestry managements （B, C and D ） and clear cutting management （A） were adopted to investigate the transformation effects after 40 years. The results show that the diameter at breast of Korean pine （ Pin~ koraiensis） in B plot is a little lower than that of A plot, but the large-size hardwood can be obtained. There are biggest differences among total volume in four kinds of sample plots in 2011. The biggest total volume is in B plot with 315.4700 m3· hm-2 followed by A plot, and the lowest one is D plot. The total volume of B plot is 14.45% higher than that of A plot. Under three close-to-nature forest managements, the amount of Betula platyphylla and Populus davidiana decrease, but the amount of valuable broad-leaved tree species of Kalopanax septemlobus （ Thunb. ） Kondz. , Fraxinus mandshurica, Juglans mandshurica and Quercus mongolica increase. The stands are converted into coniferous and board-leaved mixed forests. The soil physical and chemical properties of B, C and D plot are improved compared with A plot. Therefore, the total volume of artificially inducing broadleaved Korean pine forests through thinning （ B plot） is high- er than that of pure Korean pine forest, the same as the soil physical and chemical properties. The total volume of D plot is lower than that of A plot, but the soil physical and chemical properties of artificially inducing broadleaved Korean pine forests through clear-cutting （D plot） are better than those of A plot. Therefore, the close-to-nature forest management is successful with best effect. Comprehensively, B plot has the best effect followed by C plot, and A plot has the worst one.