Tree regeneration play an important role in affecting community dynamics and future forest structure and functioning. Seedling growth, as the key part of tree regeneration, is strikingly influenced by multiple abiotic and biotic factors, e.g., light availability, conspecific density and soil fungi. However, the interactive effects of these factors on seedling growth are poorly understood.

To address the knowledge gap, a research team lead by Dr. WANG Xugao and Dr. LIN Fei from Shenyang Institute of Applied Ecology of the Chinese Academy of Sciences conducted a controlled pot experiment for seedlings of two dominant tree species in northeast China, i.e., ash (Fraxinus mandshurica) and linden (Tilia amurensis) at two levels of light availabilities (30 and 80% of full light) which were modelled by different filters, and two conspecific densities (2 and 8 seedlings) with soil collected from underneath conspecific adult trees. To measure the effects of soil fungi, the Illumina high-throughput sequencing technology was used to investigate soil fungal communities. The two species in this study have different functional traits. Ash is shade-intolerant and arbuscular mycorrhizal fungi (AM)-associated species, whereas linden is shade-tolerant and ectomycorrhizal fungi (EM)-associated species.

Results showed contrasting effects of light availability, conspecific density and soil fungi on seedling growth of ash and linden. Ash seedlings were more suitable for the environments of higher light and fewer conspecifics, whereas linden seedlings tended to prefer the environments of relative lower light and more conspecifics under which a higher proportion of EM fungi was in the soil. Moreover, the response differences of species were related with their own traits, such as shade tolerance and mycorrhizal type.

This study entitled “The effects of light, conspecific density and soil fungi on seedling growth of temperate tree species” was published in Forest Ecology and Management and it was supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China.

Fig.1. The effects of light availability and conspecific density on seedling growth of ash and linden (Image by YIN Jin).

Fig 2. Relationships between linden seedling growth and soil fungi (Image by YIN Jin).