An article has just been published in “Science of The Total Environment” about the importance of species identity, species mixing and understory on carbon and nitrogen stocks in sessile oak and Scots pine stands:
Korboulewsky, N., Javoy, T., Pérot, T., Ouimet, R., 2025. Importance of species identity, species mixing and understory on carbon and nitrogen stocks in sessile oak and Scots pine stands. Science of The Total Environment 1000, 180410. https://doi.org/10.1016/j.scitotenv.2025.180410
Highlights:
- Species identity has a greater effect on C and N stocks than does species composition.
- The effect of mixing species is limited.
- The understory accounts for up to 29 and 49 % of the vegetation C and N stocks.
- Root biomass is the main source of uncertainty.
- The main challenge for foresters is to maintain stocks rather than to increase them.
Abstract:
Forests contribute the most to the carbon stocks of the terrestrial biosphere. Estimates are available at different scales, though a large degree of uncertainty remains. In particular, the understory is seldom taken into account. In this study, we measured the carbon and nitrogen stocks of all ecosystem compartments, including trees, understory, deadwood, and soil, in pure sessile oak, pure Scots pine and mixed stands of the two species. We studied the importance of different compartment stocks and the effects of stand composition. We also evaluated different sources of uncertainty related to the calculation parameters of the estimates.
We found that species identity affected ecosystem C and N stocks more than stand composition did. The effects were primarily observed in the forest floor (mainly the organic layer) and the understory. No stand composition effects were observed for either soil C stability or C and N stocks in the mineral horizons, indicating that physicochemical processes dominate. Our results show that the understory can account for more than a quarter of vegetation C stocks and up to one-half of vegetation N stocks in pine low density stands. This importance of the understory was most significant in low-density pure pine stands. The root biomass of the trees and understory vegetation were the primary sources of uncertainty in stock estimations.
Graphical abstract:
