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Human Carbon Footprint: How does biodiversity help to increase carbon storage?

CGTN | January 5, 2023


According to National Forestry and Grassland Administration, China has the largest area of artificial forest in the world, accounting for more than one-third. But monoculture makes it fragile.

In Qianjiangyuan National Park in southeastern China's Zhejiang Province, young scientists are about to take some special pictures for the trees, a basic step for a more ambitious goal to upgrade the artificial forest. 

They use LiDAR, which is an active remote sensing system that can be used to measure vegetation height across wide areas, in the foundation to record the three-dimensional structure of the entire forest. Lasers help scientists understand natural forests in a whole new way.

How do we use the laws of nature to build artificial facilities and systems? 

Monoculture is not workable. Basic research can provide solutions to which tree species can grow together to achieve efficient carbon storage, which could help realizing the combination of biodiversity conservation and climate change mitigation. Whether it is lab research or natural forest research, it has been proved that diversity is beneficial to forest ecosystem productivity and carbon storage.

But why and how does biodiversity improve carbon storage? 

Chinese researcher Liu Xiaojuan has set up a decade-long experiment, not in the lab, but in nature. About half of the weight of trees is carbon. The bigger they grow, the more carbon they capture. Liu compares sample lands from monoculture forest to forests with 2 to 24 tree species. A diverse plot with 24 species is the level of the natural forest in Qianjiangyuan. 

They compared the carbon storage per Mu of monoculture pure forest with 16-species forest, and found that after 8 years, the carbon storage of 16-species forest is twice that of a pure forest.

Researchers have found that a diversified forest can establish an invisible network. Roots intertwine to exchange water and microbes. The canopy crosses and they avoid each other to maximize sunlight intake. And insects move through a network of leaves. They form one entity. 

When the diversity in a forest increases, a kind of interaction will be formed between the different species, so that they can all survive, and can maximize the interaction to absorb more nutrients together. This is a complementary effect.

At this time, using this data, researchers can reconstruct the interactional relationship. For any individual tree, the rate of growth is actually relative to its neighbors. If researchers combine the data from different altitudes, they can conclude a more suitable combination of this tree species.

Nature just taught us how to plant trees. What we need is action. Liu said that ideally they wanted to see the highest diversity, but actually when people were reforesting, the biggest increase in carbon storage was from monoculture pure forest to 2-species forest. So researchers have taken the first step, and they can develop in a better direction later.

Ma Heping, a researcher of Chinese Academy of Sciences, said that the solution to carbon neutrality still depends on green vegetation to fix carbon. And Chinese researchers really hope that experts from developed countries can pay more attention to and support developing countries. Ma believes that only in this way can the whole world be harmonious and the problems we face be resolved.