Impact of Multi-Dimensional and Dynamic Distance on China's Exports of Wooden Forest Products to Countries along the "Belt and Road"

National distance (ND) is the key factor that affects international trade but the traditional trade gravity model only considers spatial distance, which is not enough. This paper therefore constructs a trade gravity model and a Generalized Moment Estimation Model (GMM) based on four dimensions-spatial distance (SD), economic distance (ED), institutional distance (ID) and cultural distance (CD)-comprehensively analyzing the impact of the heterogeneity represented by national distance on exports of wooden forest products (EWFP) from China to countries along the "Belt and Road" using panel data from 2001 to2018. The results show that the impacts of the four types of ND on China's EWFP are different and that a major change has taken place since the "Belt and Road" initiative was proposed, within which CD has become the key factor that hinders exports, while the traditional SD is not significant. Therefore, using NDs instead of the SD of the traditional trade gravity model is much more reasonable. Finally, this paper proposes some suggestions to reduce the ND between China and the route countries and to promote cooperation among them.