What’s in store for carbon storage?
Written by Nikki Read, edited by Bethany Bradley
Summary
Carbon sequestration both aboveground and belowground by trees is an important form of climate change mitigation. Tree species differ in their ability to store (i.e. total carbon in above and belowground pools) and sequester (i.e. year to year changes in carbon storage) carbon. Given fast growth rates of many introduced trees, Lázaro-Lobo et al. (2023) hypothesize that non-native trees might be better at storing and sequestering carbon than native trees. Lázaro-Lobo et al. (2023) used data from the Spanish National Forest Inventory to examine the impacts of forest origin (native vs. non-native), climate type, dominant tree species, and whether the trees were planted or natural on forest carbon storage and sequestration. They found that non-native forests had higher carbon storage than native forests in both wet and dry climates and higher carbon sequestration in wet climates. However, much of the pattern related to origin was driven by a few specific species. In Spain, non-native Eucalyptus globulus had among the highest carbon storage and sequestration, while non-native Pinus radiata had among the lowest carbon storage and sequestration. Several trees native to Spain, including Quercus ilex, Quercus petraea, and Pinus pinaster had comparably high rates of carbon storage and/or sequestration to E. globulus. E. globulus is a widespread non-native tree in Spain, thus the authors’ general finding of higher carbon storage in non-native forests is likely driven by non-native Eucalyptus forests. Lázaro-Lobo et al. (2023) also compared carbon storage for natural forests versus plantation forests for eight native trees and found that plantations tended to store less carbon than natural forests but had no difference in carbon sequestration rates. This may be due to high tree densities and lack of silviculture practices to regulate stand structure in plantations, which can promote competition and lead to smaller tree diameters, or due to plantations occurring in areas with high erosion and low productivity soils.
Take Home Points
The dominant tree species had the largest effect on carbon, with non-native E. globulus forests consistently storing and sequestering among the highest amounts of carbon in wetter environments.
Water availability (wet vs. dry) has a significant effect on carbon sequestration, with native species likely to be better adapted in drier habitats.
Management Implications
Plantations tended to store less carbon than natural forests dominated by the same native tree species.
While selected non-native species like Eucalyptus spp. may store more carbon than native species, they can also have negative effects on biodiversity and other ecosystem services.
Keywords
Management efficacy, carbon storage, carbon sequestration