A global research initiative has determined that forests with a mix of species are more effective at carbon sequestration than those with only one species. Particularly, forests with a combination of four different species show the highest efficiency. These diverse forests not only withstand environmental threats better but also offer increased ecosystem services and support a wider range of biodiversity. However, many national forest restoration programs still predominantly adopt a single-species approach.
In these mixed forests, the amount of carbon stored above ground is over 70% greater compared to single-species forests, with the highest increase observed in forests containing four different species.
Forests play a critical role in absorbing and storing carbon, contributing to achieving global net zero objectives. While numerous countries have pledged to expand their forest cover, predominantly by planting single-species forests, an international team of researchers has explored how carbon storage in mixed forests compares to that in monocultures. Their findings indicate that mixed forests have a superior capacity for carbon storage, especially those with a quartet of species.
Forests with a variety of tree species are found to be 70% more efficient as carbon sinks than their monoculture counterparts.
To mitigate climate change impacts, preserve biodiversity, and accomplish sustainable development goals, reforestation is essential. Restored forests, especially mixed ones, store carbon in soil, shrubbery, and trees. Diverse forests are not only more effective at carbon storage due to the complementary traits of different species, but they are also more resilient to pests, diseases, and climate changes, enhancing their ability to store carbon long-term. Moreover, these forests offer greater ecosystem services and support a higher level of biodiversity.
Studies highlight that mixed forests, especially those with four different species, excel in carbon storage and ecological benefits compared to monocultures. Despite these advantages, the current trend in forest restoration heavily leans towards monocultures.
Table of Contents
Current Practices in Forest Restoration
Despite the known advantages of varied forest ecosystems, many countries still focus their restoration efforts on monoculture plantations. An international group of scientists compared the carbon storage in mixed planted forests to that in commercial and the most effective monocultures, including average monocultures.
Dr. Emily Warner, a postdoctoral researcher in ecology and biodiversity science at the University of Oxford’s Department of Biology, and lead author of the study published in Frontiers in Forests and Global Change, remarked, “Diverse planted forests store significantly more carbon than monocultures – over 70% more. The greatest increase in carbon storage, compared to monocultures, was found in four-species mixes.”
Research on Species Richness
The research team reviewed studies since 1975 that directly compared carbon storage in mixed and single-species forests, integrating this with new data from a global network of tree diversity experiments. “Our aim was to consolidate existing evidence to assess whether forest diversification enhances carbon storage,” explained Warner.
The mixed planted forests in the study varied in species richness, ranging from two to six species. In the data analyzed, the four-species mixes proved to be the most effective carbon sinks. For example, one such mix consisted of different broadleaf trees commonly found in Europe. Mixes with two species also showed higher aboveground carbon storage than monocultures, storing up to 35% more carbon. However, forests with six species did not display a clear advantage over monocultures. The study conclusively demonstrated that forest diversification significantly boosts carbon storage, with mixed forests having 70% higher aboveground carbon stocks than average monocultures. It was also found that mixed forests had 77% higher carbon stocks than high-yielding commercial monocultures.
Implications for Future Forest Management
Dr. Susan Cook-Patton, a senior forest restoration scientist at The Nature Conservancy and a collaborator on the study, emphasized, “As the drive for tree planting intensifies, our research underscores the benefits of planting mixed species to enhance carbon storage and other advantages of diversifying planted forests.” The findings are particularly instructive for forest managers, showing a productivity benefit in diversifying newly planted forests, the researchers noted.
While highlighting the increased carbon storage potential of mixed forests, the researchers also acknowledged limitations in their study, including a general scarcity of research on mixed versus monoculture forests, particularly those that are older or have higher tree diversity.
“This research underscores the potential benefits of diversifying planted forests and the necessity for long-term experimental data to further investigate the mechanisms behind our findings,” Warner stated. “It’s crucial to delve deeper into how the carbon storage advantages of diversification vary based on factors like location, species selection, and forest age.”
Reference: “Young mixed planted forests store more carbon than monocultures—a meta-analysis” by Emily Warner, Susan C. Cook-Patton, et al., 9 November 2023, in Frontiers in Forests and Global Change.
DOI: 10.3389/ffgc.2023.1226514
Frequently Asked Questions (FAQs) about Mixed-species forests
Do mixed-species forests store more carbon than monocultures?
Yes, mixed-species forests store significantly more carbon than monocultures. Research indicates that these forests, especially those with four different species, have above-ground carbon stocks that are at least 70% higher than in single-species forests.
How does species diversity in forests impact their resilience?
Diverse forests are more resilient to environmental threats such as pests, diseases, and climatic disturbances. This increased resilience not only helps in maintaining biodiversity but also enhances the forests’ long-term carbon storage potential.
What are the ecological benefits of mixed-species forests compared to monocultures?
Mixed-species forests offer greater ecological benefits including higher levels of biodiversity, better ecosystem services, and increased resilience to environmental threats. They are also more effective carbon sinks, contributing to climate change mitigation.
Why are current forest restoration efforts focused on monocultures?
Many countries’ forest restoration efforts are focused on monocultures due to commercial and operational reasons. However, this approach overlooks the benefits of mixed-species forests in terms of carbon storage, biodiversity, and ecological resilience.
What does the research suggest for future forest management?
The research suggests that incorporating a mix of species in forest restoration and management can significantly enhance carbon storage and other ecological benefits. This approach is recommended to meet global net zero targets and support biodiversity.
More about Mixed-species forests
- Mixed-Species Forests and Carbon Storage
- Benefits of Forest Biodiversity
- Comparing Monocultures and Mixed Forests
- Forest Restoration Practices
- Carbon Sequestration in Forests
- Ecological Resilience of Diverse Forests
- Global Net Zero Targets and Forest Management
4 comments
good article but theres a lot of technical stuff that goes over my head, wish it was a bit more layman-friendly, you know? also, how does this affect regular people, like what can we do?
Wow, didn’t know that mixed forests were this much better at storing carbon. It’s kinda surprising that we’re still focused on monocultures then? Shouldn’t we be changing our approach fast.
interesting read! the part about mixed forests being more resilient to climate changes and diseases is really important, shows we need to rethink how we do forest restoration…
I think the study is really valuable, but how do we ensure that this information reaches the right people? like policymakers and forest managers. They’re the ones who need to act on it.