Abstract
Although decades of research suggest that higher species richness improves ecosystem functioning and stability, planted forests are predominantly monocultures. To determine whether diversification of plantations would enhance aboveground carbon storage, we systematically reviewed over 11,360 publications, and acquired data from a global network of tree diversity experiments. We compiled a maximum dataset of 79 monoculture to mixed comparisons from 21 sites with all variables needed for a meta-analysis. We assessed aboveground carbon stocks in mixed-species planted forests vs. (a) the average of monocultures, (b) the best monoculture, and (c) commercial species monocultures, and examined potential mechanisms driving differences in carbon stocks between mixtures and monocultures. On average, we found that aboveground carbon stocks in mixed planted forests were 70% higher than the average monoculture, 77% higher than commercial monocultures, and 25% higher than the best performing monocultures, although the latter was not statistically significant. Overyielding was highest in four-species mixtures (richness range 2–6 species), but otherwise none of the potential mechanisms we examined (nitrogen-fixer present vs. absent; native vs. non-native/mixed origin; tree diversity experiment vs. forestry plantation) consistently explained variation in the diversity effects. Our results, predominantly from young stands, thus suggest that diversification could be a very promising solution for increasing the carbon sequestration of planted forests and represent a call to action for more data to increase confidence in these results and elucidate methods to overcome any operational challenges and costs associated with diversification.
Original language | English |
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Article number | 1226514 |
Number of pages | 12 |
Journal | Frontiers in Forests and Global Change |
Volume | 6 |
DOIs | |
Publication status | Published - 9 Nov 2023 |
Bibliographical note
Funding:EW’s PhD was funded by the Natural Environment Research Council NE/L002612/1, Oxford-NERC Doctoral Training Partnership in Environmental Research. The Bezos Earth Fund supported SC-P’s time on this work. NE and OF gratefully acknowledge the support by the German Centre for Integrative Biodiversity Research (iDiv) funded by the German Research Foundation (DFG–FZT 118, 202548816). The contribution of PR was supported by the U.S. NSF Biological Integration Institutes grant DBI-2021898.
Keywords
- forest
- tree diversity
- biodiversity
- ecosystem functioning
- plantation
- climate mitigation
- aboveground carbon stocks
- nature-based solution