天保工程实施以来东北阔叶红松林的可持续经营

20世纪末以来有两个重要的变化影响着东北温带阔叶红松林资源的可持续性,一是天然林资源保护工程(下称天保工程)的实施,另一个是红松不再作为用材树种被采伐。但森林采伐后的更新造林模式并没有显著改变。以长白山腹地-露水河林业局的阔叶红松林为研究对象,利用森林资源清查(二类)和作业设计调查(三类)资料,评估了这两个重要的变化对当前的森林资源的产生影响。结果表明,天保工程的实施调减了采伐量,间接提高了森林的公顷蓄积量,整体上促进了森林资源的恢复。目前,紫椴,蒙古栎,水曲柳和春榆等占商品材总生产量94.7%(蓄积量)。与此同时,可供采伐的这4个树种年生长量却小于采伐量,而林下补植红松,却忽视阔叶树更新的经营模式势必会逐渐增加红松在阔叶红松林中的比例,使目前商品材资源不足的情况更加恶化。总的来说,天保工程促进了公益林区森林资源的可持续性,但降低了用于木材生产的商品林的面积;红松不采伐增加了红松在商品林中的比例,降低了商品林中用材树种比例和商品材的可持续生产能力,从长期看,必然导致可采伐林木资源的枯竭。据此,建议应根据森林培育的目标,选择合适的森林更新恢复模式。

Forest management of Korean pine and broadleaf mixed forest in Northeast China since the implementation of Natural Forest Protection Project

Since the end of the last century, two major changes in forest management policy and strategies have been affecting the sustainability of natural Korea pine (Pinus koraiensis) and broadleaf mixed forest (KBF): implementation of Natural Forest Protection Project (NFPP) and no-cutting Korean pine which was taken as a important timber and logged all the time. However, the post-harvest regeneration has not changed correspondingly. Planting Korean pine is continually the only one way to promote natural regeneration, while broadleaf tree species is ignored in the management systems. In order to explore the effect of current management pattern on the sustainability o KBF, this study evaluated the availabilities of forest resources utilization in typical KBF region. The results showed that the implementation of NFPP has decreased harvesting quota, increased forest unit-area volume and then indirectly promoted KBF restoration. Since Korean pine has not been harvested at around of the end of the last century, four broadleaf tree species, including Tilia amurensis, Quercus mongolica, Fraxinus mandschurica and Ulmus japonica occupied 94.7% of total amount of timber production, however, their growing increase in standing timber in commercial forest are lesser than that of felled lumber, suggesting that the timber resource are getting deficit and not sustainable. While the forest management model "planting coniferous and cutting broadleaf" has gotten the situation worse. In the processing of keeping coniferous tree survival, a large number of broadleaf, the four timber tree species among them, are removed because of probably affecting conifer tree live. As a consequence, broadleaf seedlings and sapling are scarce in stands floor. In general, the two major changes has indirectly caused forest resource restoration and increased the sustainability of KBF in welfare forest area. At mean time, they has consistently increased the dominance of Korean pine in the KBF stands, reduced the capacity of standing timber in commercial forest, and then decreased the sustainable utilization for timber. Out results indicated that the current forest management will tend to rapid depletion of standing timber in KBF distribution area. Therefore, this study suggested that suitable forest management should adapted to forest planning, management targets, stand situations.