Emerald Ash Borer – Frequently Asked Questions

The emerald ash borer is only known to attack true ash trees (Fraxinus spp.). These trees include: white ash, green ash, black ash, pumpkin ash and blue ash. EAB is not known to attack mountain ash, or other common forest species like maples, oaks, or beech.

If you have a woodlot and it contains ash, you will likely have EAB present on your property. Signs and symptoms of an EAB infestation in your ash may include treetop dieback, peeling bark, woodpecker feeding holes (they feed on the larva under the bark) and small D-shaped holes on the tree trunk. You may also see new branches growing out from the trunk, roots and branches of the trees. Your trees may be infested even without obvious signs and symptoms as once these signs become apparent, EAB has been established for some time and tree death is imminent. The emerald ash borer can kill a perfectly healthy tree within three years.

EAB cannot be stopped from spreading throughout your woodlot. The beetle is effective at moving from tree to tree by flight, traveling up to 10km per year. EAB has been spread much greater distances by the human movement of infested material such as firewood, nursery stock, logs, branches, and wood chips. It is recommended to help “slow the spread” of the insect by not moving ash material. In fact, it is illegal to move ash material to locations outside the Canadian Food Inspection Agency’s (CFIA) Regulated Area.

EAB is probably already in your woodlot, but even if you aren’t sure or haven’t seen any evidence of the insects’ presence, it’s still a good idea to ask a forestry professional for an assessment. A forestry professional can confirm the presence of the insect, predict long-term impacts on your woodlot, provide advice related to potential mitigation techniques (such as sustainable harvesting and/or tree planting), and make you aware of any assistance programs potentially available to you.

Depending on your situation, you may be interested in obtaining a management plan from a Registered Professional Forester or Managed Forest Plan Approver. A management plan can give you direction on how best to look after your woodlot. You may also be eligible for considerable tax savings through the Managed Forest Tax Incentive Program.

Actively managing your woodlot in the face of EAB can help you maintain or increase both the economic returns and personal benefits you receive from your property. By actively managing your woodlot you can promote greater species diversity, decrease the opportunities for the establishment of undesirable species and generally increase your woodlots’ overall health and vitality.

Although it might seem logical to remove all your ash trees, this action could have undesired consequences and is not recommended. Depending on the amount of ash in your woodlot, significant damage (i.e. flooding, blow down of trees, or increased opportunities for undesirable or invasive species like European buckthorn to become established) may result. It is recommended that you seek advice from a forestry professional regarding which ash trees to remove, and over what period of time.

In the guide book “Preparing for Emerald Ash Borer, a Landowner’s Guide to Managing Ash Forests” the authors provide several recommendations including selective ash removal without over-harvesting, removal of defective or diseased trees, retention of non-ash species as “crop” trees, promotion of regeneration of non-ash tree species, and conservation of other values.

Active management of woodlots with an ash component before EAB arrives makes a lot of sense; however, even though the EAB is already present in most woodlots, it’s not too late. EAB damage is primarily confined to the outer portions of the tree, so affected trees may still be valuable for lumber and other wood products if detected early and processed quickly. The value of the wood degrades rapidly once the tree dies and wood staining and decay processes begin.

It is best to hire a professional forester who can guide you through the process of obtaining a tree cutting permit (called a Good Forestry Practices Permit) and help you sell your wood to a reputable logger. For more information on selling standing timber, please visit the Ontario Woodlot Association website.

The Canadian Food Inspection Agency (CFIA) regulates invasive species (such as EAB) and the movement of potentially infested material in Canada. The CFIA has delineated a “Regulated Area” from which ash material as well all species of firewood (not just ash), cannot be transported.

Within the Regulated Area for EAB. Firewood can technically be moved within the Regulated Area without special permits. However, to help slow the spread of the insect, the best practice is to not move firewood to a new location. Buying firewood locally and burning all of it on-site is a wise management principle that has implications for other invasive species (i.e. the Asian long-horned beetle).

If you are going camping, your campsite may actually be in an area that does not yet have the insect. See the CFIA website for the most up to date map of regulated areas in Canada.

In a woodlot with a low ash component, there may be little noticeable impact. However, in stands with a larger proportion of ash, you may notice several long-term changes. On wet sites, the water table may rise causing local flooding. Your woodlot may become more susceptible to wind-throw or storm damage. Unwanted, invasive species such as European buckthorn, Manitoba maple, dog-strangling vine, and lilac may crowd out your native species. Competitive undergrowth of native shrubs (e.g. raspberry) may also become an issue and make it challenging for trees to become established, or for future under-planting to take place.

Your woodlot may take many decades to recover from the total and abrupt loss of ash trees on the site. Through active management, a forestry professional can help you make appropriate decisions to help alleviate some of these impacts.

Consider having a consultant write a Forest Management Plan for your property. Not only will this plan assist you with decisions pertaining to your ash trees, it will help you plan and schedule all activities in your woodlot for the next 10 years.

(Also, for those landowners not classified under the Farm Property Class Tax Rate, significant property tax savings can be realized under the Managed Forest Tax Incentive Program. See the website for more information).

To help alleviate the impacts of EAB, diversifying the species of trees in your woodlot should be a primary objective. Undertaking a partial harvest operation may help open up the canopy to encourage new growth of different tree species and may help capture the value in ash trees before they are killed by EAB.

It depends on your situation. If you have a diverse woodlot, with a variety of tree species that can naturally re-seed into the woodlot, under-planting may not be necessary. If desirable seed trees are lacking, under-planting may be the best option to increase species diversity and ensure you maintain the health of your woodlot. A forestry professional can advise you of options, costs and any assistance programs available.

The selection of species should be based on your site and soil type (texture, depth and drainage). For lowland ash sites with poorly drained soils, consider planting red maple, silver maple, bur oak, eastern white pine, eastern white cedar, balsam poplar, balsam fir, larch, yellow birch, shagbark hickory or white spruce. On drier sites with better drained soils, sugar maple, red oak, beech, white birch, black cherry, basswood, bitternut hickory, white pine and hemlock are recommended.

Availability of seedlings may be limited in your area. Call your local Conservation Authority, forestry consultant or a local tree nursery to discuss your options and find out more.

Rather than trying to remove the seedlings and saplings in your woodlot, it is more feasible to encourage the establishment of other species that are suited to the site. They will increase diversity and fill the gaps created as existing ash trees die. It is recommended that landowners focus on increasing the species diversity through planting and the retention of desirable seed trees of alternate species.

For woodlot owners who are interested in planting trees in forest gaps created by dead or dying ash, funding support may be available through Forest Ontario’s 50 Million Tree Program. Interested landowners can apply here.

Yes. If you are a residential or business owner, you should speak with an ISA certified arborist to determine the health of your ash tree(s) and what action should be taken. For woodlot owners who want guidance on management actions, you should seek the advice of a registered professional forester.

For residential landowners or rural landowners with a small number of ash trees, there is an insecticide treatment available to help mitigate the effects of EAB. The treatment works best if the insecticide is applied before the trees are infested or when the infestation is at an early stage. Signs or symptoms of an infestation are not always obvious, and once the infestation has established it is too late to apply the insecticide.

Insecticide treatments must be administered by a tree care professional with a pesticide license. Treatments occur every two years, or annually in situations where EAB pressure is high (i.e. nearby ash trees are infested). To treat an ash tree on your property, contact an ISA certified arborist or other tree care professional.