Tree diversity linked to stronger forest responses to climate extremes

What you need to know

• Compound extremes generally reduced forest resistance and recovery more than individual extremes. Heat combined with drought was particularly damaging, highlighting the effects of climate shocks that occur together. 13
• Tree-species richness was positively associated with resistance and recovery across both individual and compound extremes. The study reports an association, rather than demonstrating that greater richness alone caused the differences between forests. 13
• Richness explained only a limited share of variation between plots. The sources describe diversity as one influence among climate, soil and other environmental factors, rather than a complete account of how forests respond. 123
• The analysis concerns forest plots in the contiguous United States. Its findings do not, by themselves, provide locally tested prescriptions for managing other forest types or regions. 12
• An independent researcher quoted by Mongabay cautioned that controlled diversity experiments have produced more variable results, including neutral or negative effects. The researcher also warned against assuming those experimental findings translate directly to natural forests. 2

Why this matters

Forests face climate extremes that can occur in combination, and this study adds evidence that tree diversity is associated with how well forests withstand and recover from them. For practitioners, it supports investigating diversity in forest management, while the limited explanatory power of richness argues against treating it as a complete resilience measure. 123

What happens next

The reported findings leave questions for further research and local application: whether the relationships hold in other forest regions, how forests respond to recurring shocks, and which management interventions produce measurable resilience benefits in the field. 12

What we know

• Researchers combined US Forest Inventory and Analysis plot records with satellite-derived vegetation productivity data, covering 88,116 plots and climate extremes from 2001 to 2020. 1
• The study defines recovery using forest productivity in the year after an extreme event. 12
• The analysis excluded consecutive extreme years, so its results do not describe shocks recurring before recovery is complete. 12

What we don't know

• It remains unclear whether the observed relationships hold across forest regions and types beyond the contiguous United States. 12
• The study does not resolve how tree diversity and recovery interact when extreme events recur before a forest has recovered. 12
• Which locally appropriate management actions can increase resilience, and whether they deliver measurable benefits in the field, remain open questions. 12

Read the reporting

This WildNews briefing synthesises and summarises reporting from the sources below. WildNews did not produce the original reporting. Learn more about how we use AI