Tree species identity determines wood decomposition via microclimatic effects

Area of Science:

• Forest Ecology
• Biodiversity-Ecosystem Functioning
• Decomposition Dynamics

Background:

• Forest ecosystem functions, including deadwood decomposition, are linked to tree diversity.
• Understanding the mechanisms requires considering not only species richness but also tree identity.
• The role of microclimate in tree diversity's influence on wood decay is increasingly recognized.

Purpose of the Study:

• To investigate the influence of tree species richness, identity, and microclimate on wood decomposition.
• To assess the interplay between tree diversity, microclimate, and soil microbial properties in deadwood decay.

Main Methods:

• A 12-year-old tree diversity experiment with six native species and varying richness gradients was used.
• Wood mass loss, soil microbial properties, and soil surface temperature were measured at high temporal resolution.
• Statistical analyses were performed to determine the impact of tree species richness, identity, and microclimate.

Main Results:

• Tree species identity significantly affected wood mass loss, soil microbial properties, and soil surface temperature.
• Scots pine presence increased wood mass loss, whereas Norway spruce presence decreased it.
• Differences in litter structure influenced soil surface temperature, directly impacting decomposition rates.

Conclusions:

• Tree identity is a critical factor in regulating forest deadwood decomposition.
• Microclimate plays a vital role, and its influence on decomposition is mediated by tree species identity.
• Effective prediction of wood decay requires considering multiple biodiversity facets and their impact on abiotic and biotic soil properties.