The Emerald Ash Borer and its Implications for Carbon Stocks

The Emerald Ash Borer (EAB), an invasive insect species native to Asia, has become a significant threat to forests across the United States since its initial detection in Michigan back in 2002. Unfortunately, efforts to stop the insect from spreading have largely failed and EAB can now be found in at least 29 states throughout the country. An EAB outbreak is characterized by the rapid and widespread mortality of all 16 species of ash trees (Fraxinus spp). The larvae of this invasive pest tunnel beneath the bark and disrupt the flow of water and nutrients leading to the tree’s death and subsequent decay.

Ash trees are typically found in mixed hardwood forests and are important contributors to carbon sequestration. As mature ash trees are killed by EAB, the ongoing loss of biomass and cessation of carbon uptake through photosynthesis diminish the immediate ability of affected forests to sequester carbon. Past and current efforts to mitigate the impact of EAB on forests have been the implementation of strategies to ‘slow the spread’ of the infestation.  These efforts have included things such as quarantines, monitoring programs, and public education campaigns.

However, it’s not all bad news.  Foresters and land managers that utilize sustainable forest management practices to enhance overall ecosystem health and resilience can mitigate the impacts of EAB on carbon stocks over the long term. Reforestation efforts aimed at replacing lost ash trees with diverse and resilient tree species can help restore carbon sequestration and storage capacity within affected forests.

By investing in proactive management strategies--such as active management processes which add diversity of species, size and age classes to forests--it is possible to mitigate the impacts of EAB (and other invasive pests) and preserve the carbon storage capacity of forests for future generations.  The Climate Trust encourages these activities to build forest resiliency against unforeseen future forest health threats in our Improved Forest Management (IFM) and reforestation projects.