Transforming the forestry development model and promoting the integrated development of the forestry industry has become an important way for forestry to break through development bottlenecks and achieve efficiency enhancement, prosperity of forest areas, and income increase for forest farmers. In this study, we have theoretically elaborated on the mechanism by which the integrated development of the forestry industry affects the income level of forest farmers. In terms of empirical research, we use the inter provincial panel data from 2005 to 2019 to empirically test the individual heterogeneity, regional heterogeneity, and spatial spillover effects of forestry industry integration on forest farmer income with the help of fixed effect model, quantile regression model and spatial panel model. Results showed that, firstly, the level of integration in the forestry industry is on the rise, with most provinces in the middle or high integration stage. Among them, the Northeast region has the highest level of integration. Secondly, there is a positive spatial correlation in the income of Chinese forest farmers, and the spatial correlation is gradually increasing. The income of forest farmers in coastal provinces is relatively high, as indicated by the presence of HH clusters. Thirdly, the integration of the forestry industry has significantly improved the income level of forest farmers, and there are group heterogeneity and regional differences. The heterogeneity of income is reflected in the increasing income effect of forestry industry integration, which continuously strengthens with the improvement of the income level of forest farmers. Regional heterogeneity is mainly manifested in the Northeastern, Eastern, and Central regions. The integration of forestry industries can significantly promote the growth of forest farmers’ income, while in the Western regions, the income increase effect of forestry industry integration has an inhibitory effect, but is not significant. Finally, the integration of the forestry industry has significant spatial spillover effect and the indirect effect is greater than the direct effect. However, the spillover effect coefficient is 0.007, which is still at a relatively low level, and the diffusion effect generated by factor flow still needs to be strengthened. Efforts to boost integrated forestry industry development will broaden the income channels of forest farmers by leveraging high productivity of the agglomeration effects, diffusion effect and demonstration effect, strengthening regional communication and cooperation, and promoting integrated forestry industry development with adjacent regions. This study helps to correctly grasp the relationship between forestry industry integration and farmers’ income, and provides decision-making reference for local governments to formulate policies for increasing farmers’ income in the development of forestry industry integration based on actual situations.

The integration of the forestry industry can effectively resolve the conflict between ecological protection and socioeconomic development while bringing new vitality and growth to traditional forestry. In this study, the level of forestry industry integration in 31 provinces in China from 2005 to 2019 was measured using the Herfindahl index method. With ArcGIS and exploratory spatial data analysis methods, the spatial-temporal distribution characteristics, dynamic change trends, spatial correlation characteristics, and existing problems in China’s forestry industry integration development were analyzed. The results showed that the total output value of forestry integrated products and the output value of each product segment increased, but the proportion of product development was imbalanced, and it was concentrated in the understory planting and collection industry and wood processing and manufacturing industry, leaving substantial room for improvement and integration. The value of the forestry industry integration index also increased overall, but the level of integration was low or moderate. In terms of time, the integration index of most provinces trended upward but failed to break through 0.73, leaving a significant gap between it and deep integration. Spatially, the level of integration of the forestry industry varied across the northeast, central, west, and east, with the central and northeast showing a higher integration degree than the east and west. China’s forestry industry integration showed a significant positive spatial correlation, indicating that spatial factors had become an important factor affecting the development of the forestry industry in various regions. Therefore, it is necessary to strengthen the relevant mechanisms of cross-border cooperation and benefit sharing. Lastly, we identified problems with the integration development of the forestry industry, including insufficient and imbalanced integration, unreasonable structural layout of integration development, and insufficient driving capacity for integration. As a result, there were phased and regional differences in the evolution of forestry industry integration.