劳动力转移和森林管护水平对森林碳密度的影响——基于福建253个村的实证研究

森林生态系统具有重要的固碳功能，有效的森林管理是提升碳密度的重要方式。随着农村劳动力转移，森林管护水平也随之变化，进而可能影响森林碳密度。为了厘清劳动力转移和森林管护水平对森林碳密度的作用机理，以提升森林碳密度。利用福建5县（区）253个村1999年与2009年的林业二类调查数据和入村调研数据，采用转换因子连续函数法评价了森林碳密度，再运用层次回归模型分析了劳动转移对森林碳密度的影响，并检验了森林管护水平对二者的中介作用。结果表明：（1）10年间森林碳密度普遍提升，但区域差异明显；空间上森林碳密度呈由南向北递增，提升率呈由南向北递减。（2）劳动力转移对森林碳密度有显著促进作用，而森林管护水平对森林碳密度有显著削弱作用，并对劳动力转移与森林碳密度之间的关系具有显著中介效应。（3）劳动力特征、采伐方式及森林自然禀赋等因素，主要通过生计依赖、生境状况和生物量对森林碳密度产生显著影响。据此提出：适当减少对森林的人为干扰，丰富林农生计来源，转变林业经营目标，科学采伐成熟和过熟林，保护天然起源林，丰富人工林树种等政策建议。

Effects of labor transfer and forest management on forest carbon density based on an empirical study of 253 villages in Fujian Province

Forest ecosystem has the function of carbon sequestration, and effective management is essential to increase its carbon density. However, as rural labor transferred, the level of forest management changed accordingly, which in turn affected the carbon density of forest ecosystem. It is necessary to clarify such influencing mechanism so as to maintain the high carbon density. Thus, based on the official forestry survey data and questionnaire survey data of 253 villages in five counties (districts) of Fujian Province from 1999 to 2009, this paper evaluated the forest carbon density by adopting the conversion factor continuous function method. Then hierarchical regression model was developed to analyze the effect of labor transfer on forest carbon density, and to verify the mediating effect of forest management. The results showed that:(1) The forest carbon density in the sample area generally showed an upward trend in the past 10 years, but presented significant regional differences in space. The forest carbon density increased from south to north, while the lifting rate decreased from south to north. (2) Forest carbon density is significantly promoted by the labor transfer and weakened by forest management, where forest management exerted a significant mediating effect on the relationship between labor transfer and forest carbon density. That is, the labor transfer can ultimately promote the increase of forest carbon density through weakening the level of forest management and reducing the human disturbance. (3) Factors including labor characteristics, harvesting methods and natural forest endowments have significant impacts on forest carbon density. Specifically, the higher the average age of the labor force engaged in forestry production in the village, the higher the forest carbon density. It is related to the reduced dependence on forest livelihoods as the workforce ages. The proportion of harvesting has a significant positive effect on the increase of forest carbon density, due to the benefits from appropriate harvesting to the stock volume and the regeneration of understory vegetation. Natural forest origin positively affects the carbon density, attributed to its abundance in tree species and better function of carbon sequestration. Single tree species negatively impact the forest carbon density, which conversely proves that richer forest tree species contribute to overall carbon density increase. To this end, suggestions are proposed as follows:appropriately reducing the artificial interference to forest ecosystem, enriching livelihood sources of foresters, transforming the objectives of forestry management, scientifically harvesting the mature and overripe forests, protecting natural origin forests, and enriching plantation tree species.