A new study in China, shows that a mix of trees can absorb twice as much carbon from the atmosphere than forests consisting of a single species.
A joint research study involving scientists from China, Switzerland and Germany, explored the effects of polyculture of trees in forests. In 2009, researchers replanted large patches of deforested areas in Jianxi province, with up to 16 different species of plants, totaling at 150,000 trees.
Plants grow by photosynthesis, requiring water, sunlight and carbon dioxide. Plants use the carbon in carbon dioxide as a building block for their structures. As a forest grows, plants trap carbon dioxide, helping mitigate the effect of greenhouse gases. This is greatly beneficial towards us, since a by-product of this process is lumber, which has a widespread of applications.
Scientists allowed the patches of cultivated forests to grow over the span of 9 years. After this maturation stage, scientists cut down 100 trees to determine the amount of carbon absorbed by the trees via biomass analysis. A staggering 47% percent of mass of the branches and trunks was carbon, vastly outperforming traditional monoculture forests. “The study shows that forests are not all the same when it comes to climate protection – monocultures achieve not even half of the desired ecosystem service,” said Bernhard Schmidt from the department of biology at the University of Zurich.
multi-species forests (left) vs. single-species forests (right)- made by me, data from Yuanyuan Huang et al.
Scientists believe that this increase in carbon absorption productivity is due the increase in plant density. Planting shrubs in the forest floor increases the plant density greatly. Taller trees receive the most sunlight, shrubs and other lower lying vegetation are accustomed to the shade of larger trees, allowing them to grow and store carbon with less sunlight.
This new research is important in combating global warming. Monoculture planting of trees is prolific in the province of British Columbia where logging is common. Planting a variety of plants will greatly increase the forest’s efficiency to absorb carbon dioxide. Increasing plant diversity also has other benefits, such as a more robust ecosystem. Increased plant diversity increases resiliency towards pests and diseases.
Pine tree beetles spreading in a forest due to monoculture- photo by Jonhall
This new research is important for all of us, as it is a direct method which we can mitigate global warming. Small change such as planting shrubs after a logging operation can greatly benefit us all. Increasing awareness of this new research can lead to more ecofriendly practices in the industry.
