Snow damage to the forest canopy is common at mid and high latitudes, but this rarely happens at lower latitudes, especially in subtropical forests. Such disturbance in subtropical forest can provide an ideal opportunity to study how light availability and topographic habitat interact among species to shape seedling recruitment pattern. 

Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) examined seedling dynamics for two years after snow damage to the canopy of Ailaoshan subtropical forest in SW China to study the relative contributions of topography and light in structuring seedling recruitment. 

The researchers used two years of seedling monitoring data after a snow damage event in an old-growth subtropical forest of Ailaoshan. The species richness and abundance of tree seedlings in the understory increased significantly after snow damage to the canopy. 

They found that both light and topography factors showed significant influence on the species richness and abundance of recruited seedlings. The majority of the species of recruiting seedling showed higher recruitment in high than in low light environments under canopy gaps and the ability to initially partition habitats across topographies. 

Topographic habitat filtering acted as a persistent force in determining the recruitment of seedlings and increases in strength with increased light-facilitated seedling recruitment. 

"Our results highlight that, in Ailaoshan subtropical forest, both light requirement and topographic specialization interact over time to play a key role in promoting coexistence of tree species through selection of individuals at the seedling stage", said Dr. YANG Jie, principal investigator of the study. 

"We suggest that long-term monitoring should be continued to better understand the sustained effects of snow damage on the regeneration of forest community and the community composition alteration following disturbance events", added Dr. YANG. 

The study entitled "Canopy openness and topographic habitat drive tree seedling recruitment after snow damage in an old-growth subtropical forest" has been published in Forest Ecology and Management.