Protecting the diversity of tree species in forests is essential for long-term carbon capture and the battle against climate change, according to a study released last week. Published in Nature, this research is the first to demonstrate the lasting benefits of tree diversity on a large spatial scale, specifically in terms of carbon and nitrogen storage in the soil.
Xinli Chen, the paper’s lead author and postdoctoral fellow in the Faculty of Agricultural, Life & Environmental Sciences, underscores the crucial role of preserving biodiversity in forests.
“Conserving tree diversity is a valuable tool in mitigating climate change, particularly in enhancing carbon storage in soil,” Chen says.
Addressing the decline in carbon and nitrogen stocks
Although it’s well-established that increasing soil carbon and nitrogen storage can alleviate climate change effects and maintain soil fertility, global stocks of both elements have significantly diminished due to factors such as forest fires, deforestation, and land use changes. By conserving and promoting tree diversity in forests, soil carbon, and nitrogen levels can be boosted.
The decline in global carbon and nitrogen stocks has led to a growing need for innovative solutions to restore balance in natural ecosystems. Tree diversity plays a pivotal role in addressing these challenges, offering a sustainable approach to mitigating the impacts of climate change.
Research links tree diversity to soil health
The researchers examined Canada’s National Forest Inventory database and employed statistical modeling to uncover new evidence linking increased tree diversity to higher soil carbon and nitrogen accumulation in natural forest ecosystems over time scales of 10 years or more.
This collaborative effort, involving scientists from Canada, Japan, and the United States, supports the conclusions of previous experiments. The research reveals that, over the long term, balancing the number of tree species in natural forests could elevate carbon and nitrogen levels in the organic soil layer by 30% and 43%, respectively.
Improving storage with diverse tree traits
Functional traits refer to the characteristics of trees, such as leaf nitrogen content and mature tree height, that affect their growth, reproduction, and survival. Increasing the diversity of these traits within a tree community can boost carbon and nitrogen storage in the top mineral soil layer by 32% and 50%. Scott Chang explains that these findings can “assist efforts to utilise forests for carbon sequestration by protecting and enhancing tree species diversity, which simultaneously benefits forest productivity now and in the future.”