Logging extraction in the Bornean rainforest. Credit: Zoe G Davies
According to a new study, tropical forests recovering from logging are sources of carbon for several years later, contrary to previous assumptions.
Tropical forests that are recovering from having actually trees eliminated were believed to be carbon absorbers, as the new trees grow quickly. A brand-new study, led by Imperial College London scientists, turns this on its head, showing that the carbon released by soil and decomposing wood outpaces the carbon absorbed by brand-new development.
The scientists say the result highlights the need for logging practices that decrease civilian casualties to enhance the sustainability of the industry. The research study, which kept track of carbon in forests in Malaysian Borneo as part of the Stability of Altered Forest Ecosystem (SAFE) Project, is released today (January 9, 2023) in Proceedings of the National Academy of Sciences.
Author Maria Mills, who began the work at Imperial and completed it at the University of Leicester, stated: “Our outcomes show that for the tropical forest we studied, logged locations are a source of carbon even a years after logging has taken place. This indicates we require to reassess their role in international carbon spending plans– we can no longer apply the blanket presumption that they are carbon sinks.”
Eddy covariance flux tower over a heavily logged tropical forest landscape within the Stability of Altered Forest Ecosystem (SAFE) Project (this is the tower used within this study). Credit: Maria Mills
Lead scientist Dr. Terhi Riutta, now at the University of Exeter, said: “A great deal of the carbon released in recuperating forests is from security damage– trees that have actually died as a result of damage throughout the logging operations left to rot, and from disturbed soil. Logged forests still have worth– we understand they have a special biodiversity — so ensuring they are likewise not launching extra carbon through much better logging practices will boost their sustainability.”
Numerous previous studies of recuperating forests have actually focused on measuring tree growth to estimate the quantity of carbon taken from the atmosphere. The brand-new research study likewise measured just how much carbon was coming from the ground (soil and dead wood) to calculate the carbon budget from the outbound and incoming carbon flows for logged and unlogged (old-growth) forest.
Logged forest plots in the study had experienced logging at different phases over the previous few years. The measurements were taken between 2011 and 2017.
To determine the carbon released from the ground, researchers used a portable carbon dioxide monitor to test patches of ground and pieces of deadwood in a number of plots monthly for several years. The team had also established a 52-meter-tall (171-foot-tall) tower above the forest canopy to continually determine the flux of carbon into and out of the forest to see whether it was a net source or sink of carbon.
They found that unlogged forested locations are usually carbon neutral, however that moderately and greatly logged tropical forest areas are a carbon source. They approximate an average carbon source of 1.75 +/- 0.94 tonnes of carbon per hectare within reasonably logged plots and 5.23 +/- 1.23 tonnes of carbon per hectare in significantly degraded plots, with emissions continuing at these rates for a minimum of one years after logging.
Co-author Professor Rob Ewers, from the Department of Life Sciences at Imperial, stated: “The measurements from the tower show us whether the forest area is a source or a sink of carbon, and the soil monitoring informs us why this is. From these measurements, we understand logged forests are still a source of carbon up to a decade after they have actually been logged, and that this mainly comes from raw material in the soil or from rotting wood.”
The team state carbon monitoring must be performed in other forests in various regions to develop a more accurate picture of how logged forests add to international carbon spending plans.
Recommendation: “Tropical forests post-logging are a consistent net carbon source to the atmosphere” 9 January 2023, Proceedings of the National Academy of Sciences.DOI: 10.1073/ pnas.2214462120.