Emerald Ash Borer

Emerald ash borer (EAB) is a non-native invasive insect that attacks and kills all North American species of ash trees (Fraxinus species).

EAB has killed tens of millions of ash trees in North America since it was first detected in the Detroit & Windsor area in 2002. It and other non-native, invasive organisms pose a serious threat to our natural systems and urban forests.

Emerald Ashborer on a leaf

EAB was detected in the GTA in 2007. It is expected to decimate the region’s ash tree population over the next decade. This will have a significant economic and environmental impact including considerable tree removal costs, public safety hazards and a loss of ecosystem services.

Toronto and Region Conservation Authority (TRCA)’s Approach for the Management of EAB aims to limit these immediate impacts as well as focus on the long term health of our forests.

Non-native invasive insects, diseases and plants are one of the greatest threats to the biodiversity and resiliency of our forests.

Emerald ash borer, Asian long-horned beetle, beech bark disease, and butternut canker are relatively recent non-native threats of concern; while chestnut blight, Dutch elm disease and LDD moth have been impacting our forests for quite some time.

Once introduced, the spread of these organisms is often accelerated or caused by the human movement of firewood and other infested material – the Canadian Food Inspection Agency has established EAB regulated areas from which the movement of certain ash material is restricted.

The most effective approach to sustainable forest management is to ensure a diverse and robust forest system that is resilient to the inevitable pest and disease outbreaks and other stressors associated with forests located within a human-dominated landscape.

TRCA has a long and active history in the effective protection, restoration and management of the forest system within its jurisdiction.

Our response to EAB focuses on identifying ecologically important ash stands, ensuring forest regeneration, selecting and protecting individual trees as seed sources and for other values with injections of TreeAzinTM, and ensuring the safety of our parks and public spaces through a comprehensive proactive removal program for all potentially hazardous Ash trees.

Sign about treating trees for Emerald Ash Borer

Ash trees have been one of the most reliable deciduous tree species used in restoration and reforestation plantings. However, due to the threat of EAB the TRCA does not currently include ash in planting projects

A list of Tree Species to Replace the Ash Component in Restoration and Reforestation Projects in the TRCA provides information on some alternative deciduous trees.

If you are a landowner and would like more information on how your property can contribute to a regionally resilient forest system, visit our private land planting webpage.

From Tragedy to Triumph: Re-purposing Ontario’s Ash Trees

Since arriving in Ontario, the emerald ash borer has destroyed millions of ash trees. How to dispose of infested trees in a way that minimizes waste and greenhouse gas outputs? Determined to help turn this ecological tragedy into a success story, Partners in Project Green and Toronto and Region Conservation have worked with City of Toronto, City of Markham and the Town of Richmond Hill to develop a sustainable solution: repurposing infested ash trees into valuable wood products.

LEARN MORE about ash tree repurposing.

To learn more about emerald ash borer

To learn more about TRCA and its Regional Partners response to EAB

If you are a homeowner and want information on EAB treatment options and guidelines for hiring tree care services