Restoring Habitat Impacted by Emerald Ash Borer
The invasive insect, emerald ash borer (EAB), has devastated ash trees at Rattray Marsh Conservation Area. We began restoring five priority ash-dense forest areas at Rattray Marsh in 2019.
Our aim is to create a healthy forest with a diversity of native tree and shrub species. Over time, this will provide quality habitat for many species of wildlife.
The Restoration Process
We’ve completed several stages of restoration work and activities continue in the five priority forest areas. These areas were selected as they were predominantly made up of ash trees and were significantly affected by the emerald ash borer.
Emerald ash borer (EAB) kills 99 per cent of ash trees. Dead and dying ash trees are unstable and can fall.
We cut down dead and dying ash affected by emerald ash borer to create a safe working space for staff within the five restoration areas or if the ash trees are near trails and pose a safety risk to visitors.
We created brush piles and spread the downed ash trees to mimic natural deadfall and to create habitat for small mammals and other wildlife. This approach also ensured that we maintained space for planting native trees and shrubs.
Initially, we managed invasive trees and shrubs in the five restoration areas. The invasive woody species were cut and treated with herbicide to ensure they did not re-sprout. We then treated the invasive seedlings, herbaceous plants, and any regrowth.
Once the invasive plants were reduced, it provided space for planting native trees and shrubs.
We monitor for new invasive plants and control as needed to help with the survival of the native trees and shrubs.
We planted 3,300 native trees and shrubs to increase biodiversity and help establish the future forest. We monitor the health and survival of newly planted trees and shrubs and take management actions as needed to either increase their chances of survival or replace them if needed.
Our efforts to ensure restoration success involve monitoring and adaptive management in the restoration areas. These efforts are ongoing and include:
Fencing to Exclude Wildlife From New Plantings
In the five priority areas, we set up temporary fences around pockets of newly planted trees and shrubs that are being heavily impacted by deer. Our monitoring found that about 50 per cent of the trees and shrubs not protected by the fencing are being browsed by deer, with up to 100 per cent of some species such as basswood, maples and birch showing browse damage. Depending on the extent of browse and if it is repeated year after year, we anticipate stunted growth or even death of these trees and shrubs.
The use of wildlife exclusion fencing is a proven technique for ensuring the survival of planted and naturally regenerated plants with excessive impacts from browsing. The fencing at Rattray Marsh has been installed with blue flagging tape which increases visibility to deer. Our monitoring program includes the use of wildlife cameras and regular perimeter checks to assess the fencing for any damage and to make repairs.
We will remove the fencing once most of the trees’ branches and foliage are out of reach of deer and the shrubs have established large, healthy branches and foliage. We expect this to take approximately five years. Trees outside of the fenced areas that die will be replaced with species that we have observed to be less desirable to deer.
Bobbex Applications to Deter Wildlife from Excessive Browsing
We are applying Bobbex Regulation #29804 on newly planted trees and shrubs in the five restoration areas once a month at Rattray Marsh Conservation Area.
Bobbex is a nontoxic pesticide, and the active ingredients are capsaicin (found in chili peppers), castor oil, dried eggs, fish meal mixture, fish oil mixture, garlic oil, meat meal mixture, related capsaicinoids, and wintergreen oil.
Bobbex’s strong odour helps protect newly planted trees and shrubs by deterring wildlife from eating them.
For more information about our use of Bobbex, please view our public notice.
We continue to monitor the native tree and shrub growth and survival in the restoration areas . We plant additional native tree and shrub species where significant mortality of planted trees and shrubs occurs. Our monitoring helps to further inform and adapt the species we choose to plant on site.
We continue to thoroughly check the priority areas for invasive species. We use spot herbicide treatments and hand pulling to ensure invasive plants do not out-compete the native plantings in the restoration areas