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The Yunnan Province of China is wet and warm enough to support magnificent forests. However, many mountains in the region are covered by a shrubland formation dominated by an unusual pine, the shrubby and multistemmed Pinus yunnanensis (Yunnan pine; Fig. 1). This formation is natural, and not the product of forest degradation; and fire appears to be a major factor explaining the features of this pine. This region has a subtropical monsoon climate influenced by both the Indian Ocean Monsoon from the west, and the Pacific Ocean Monsoon from the east. The climate has prominent seasonality in temperature and precipitation, alternating a warm dry season (December to May) with a hot wet season (June to November; Chen et al. 2019). The annual dry season creates conditions that can favor wildfires. Fires are currently common mainly between February and April (Zhao et al. 2009), with area burned depending on the variations in annual precipitation (Chen et al. 2014, Ying et al. 2017). The shrubby pines are found in the upper portions of the landscape, where it is drier and fires are more frequent. The Yunnan pine has several adaptations to frequent crown fires, which suggests that fires have long existed in the region and are not just a product of recent human activity (see Shao et al. 2012 for evidence of paleofires in the region). These fire adaptations include (Fig. 1) serotiny (Su et al. 2015), basal resprouting, and high precocity (<5 yr), a mix of traits that is relatively rare in pines (Keeley and Zedler 1995, Rodríguez-Trejo and Fulé 2003, Pausas 2015). Pinus yunnanensis often co-occurs with Keteleeria evelyniana (Pinaceae) which has a thick insulating bark (Li et al. 2017) and epicormic resprouting. All this emphasizes the importance of fire in the ecology of the region (Su et al. 2015, Han et al. 2018).

Understanding the determinants of post–fire regeneration is critical for determining an appropriate restoration program following fire disturbances. However, studies addressing the drivers of post–fire regeneration of forests in monsoon climate are rare. This study explored the temporal and spatial variations of post–fire forest regeneration in the Central Yunnan Plateau of Southwest China, and disentangled the direct and indirect effects of the environmental factors via structural equation models (SEMs). We found that the overall post–fire regeneration density was generally greater for the habitat with higher values of elevation, pre–fire abundance, and soil pH. Post–fire regeneration was mainly composed of resprouts; seedlings were less relevant and appeared later. The SEM approach showed more variation of recruitment in resprouting (R = 0.66) than seeding (R = 0.33), and revealed different direct and indirect pathways. Resprouts were widely distributed, and significantly influenced by pre–fire abundance, elevation, soil pH, and years since the last fire. In contrast, seedlings preferentially occurred in infertile habitats, and were mainly influenced by topographic position and soil nutrients, showing distinct distribution from that of resprouts. Overall, forests under the subtropical monsoon climate in the Central Yunnan Plateau were resilient to fire mainly due to rapid post–fire resprouting. These findings indicate the complementary roles of resprouting and seeding in post- fire regeneration, and help to understand the mechanisms that regulate post-fire plant regeneration in a spatially heterogeneous landscape. Our results should contribute to improving the post–fire management of forest ecosystems under the influence of a semi–humid monsoon climate.