Watershed Health

Forest Health & Management

forest management

Forests in the Niagara Peninsula watershed provide ecological, social and economic benefits.

They provide habitat for birds, animals, amphibians and plants, and places for people to hike and enjoy nature. Forests help moderate the cycle of spring floods and summer droughts and improve air quality by absorbing pollutants and carbon dioxide. They provide forest products such as timber, firewood and maple syrup.


The NPCA is committed to sustainable forest management practices and recognizes social, economic and ecological values as important components of its forest management activities. Managing existing forests and increasing forest cover is an important aspect of sustaining the health of the watershed. The NPCA manages approximately 2,041 hectares (5,043 acres) of forest within its 41 conservation areas, with the goal of enhancing and increasing that area through reforestation activities.


Much of the forest cover of the Niagara Peninsula watershed is on private lands. Landowners are important partners in protecting and improving the watershed's forests. Owners of more than four hectares (10 acres) of forest, including newly planted areas, may be eligible for a tax reduction. Visit Managed Forest Tax Incentive Program for more information.

Many municipalities, such as the Niagara Region, Haldimand County, the City of Hamilton, and the Town of Niagara-on-the-Lake have woodland conservation or urban tree-cutting bylaws for trees and forests on private property. Before cutting down trees, be sure to contact your municipality.

forest health 


The European Spongy Moth (previously known as the Gypsy Moth) is an invasive defoliating insect that feeds on a variety of tree species found in the Niagara Peninsula watershed and throughout North America. The NPCA’s forest management program focuses on controlling outbreak levels of spongy moth in its conservation areas with trees that are at risk of defoliation, typically oak dominant forest areas. Spongy moth can cause significant tree mortality resulting in negative ecological impacts on forest health and increased hazard tree removals.


NPCA staff conduct egg mass surveys in conservation areas to identify areas infested with spongy moth. These surveys allow staff to delineate the infested areas and to forecast spongy moth population levels for the following spring. Areas with high numbers of egg masses that are at risk of being defoliated are candidates for treatment.

To control growing populations of spongy moth, the NPCA conducted an aerial spray an organic pesticide on 65 hectares of mature hardwood forest at the Chippawa Creek Conservation Area in the late May and early June 2021. Aerial applications by helicopter will take place over affected forest areas at the conservation area. Spray timing depends on insect and tree development and is weather dependent. 

The organic insecticide that is used contains a naturally occurring soil bacteria, Bacillus thuringiensis kurstaki (Btk). Its use is approved by Health Canada, including for aerial application over urban areas. Btk has been in use for more than 30 years and Health Canada states that it poses little threat to human health. When ingested, Btk impacts young moth and butterfly caterpillars, and has very little impact on other insects, birds or mammals. It does not impact moth and butterfly species, like monarchs, whose caterpillars emerge later in the season.

The NPCA does not conduct or fund aerial spray applications for private landowners. Landowners with forested area impacted by Spongy Moth are encouraged to contact aerial pesticide professionals to have their property treated.

control measures for landowners 

Manual methods can help to minimize the impact of spongy moth on small and individual trees. These methods are ineffective when populations are high and over large, forested areas.

Hand Pick Caterpillars

From May to July, handpicking caterpillars is most effective on small newly planted trees, shrubs, and plants infested with spongy moth. If possible, gently shake the tree so caterpillars fall from leaves. Thoroughly inspect the remaining foliage, branches, and trunk for caterpillars and using gloves, pick them off your tree. Fallen and collected caterpillars should be placed and left to soak in soapy water to destroy them.

Burlap Banding

From May to September, once the Spongy Moth caterpillars grow to about an inch (2.5 cm) in length by mid-June, they will move down the trunk to seek shelter from predators and heat. Reduce the number of larvae on the trees in your yard by trapping them.

Required Supplies:

  • Burlap cloth
  • Twine or rope
  • Bucket of soapy water. (Dish soap works well)

Step-by-Step Instructions:

  • Wrap and secure a piece of burlap cloth around the stem/trunk of your tree.
  • Tie twine or rope around the center or slightly below the center of the burlap.
  • Drape the burlap cloth over the twine or rope so there is an overhang where the caterpillars can crawl underneath to seek shelter during the day.
  • Check the trap by lifting the overhanging burlap cloth every afternoon and collect any hiding caterpillars.
  • Put them into a bucket of soapy water for a few days to destroy them.


From August to May, survey your property for egg masses and scrape them off surfaces into soapy water to destroy them.

Required Supplies:

  • A flat object such as a butter knife or plastic paint scraper
  • Catchment container or bag to collect the egg masses
  • Bucket of soapy water. (Dish soap works well)

Step-by-Step Instructions:

  • Place your catchment container below the egg mass.
  • Use your scraper tool to remove the egg mass from the surface. Ensure that all eggs are scraped. Try not to leave any residual eggs in bark ridges or crevices.
  • Empty the contents of your catchment container or bag into a bucket of soapy water.
  • Leave the eggs sitting in the bucket for a day or two, then dispose of the contents.

Egg masses can be located high up in trees. Care needs to be taken if trying to access anything aloft, especially if using ladders. Some private tree care companies can be hired to provide this service at heights.


The Emerald Ash Borer (EAB) is a shiny emerald coloured beetle that kills ash trees. Ash is found throughout forests in the Niagara Peninsula watershed, especially in the southern portion, and was commonly used as a street or landscape tree. EAB is an invasive pest and was first noticed in North America in 2002, in the Detroit-Windsor area.

EAB larvae feed just beneath the bark of ash trees and disrupt the movement of water and nutrients. Once signs and symptoms of infestation develop the tree is in irreversible decline. Once dead, ash trees tend to fall apart, dropping bark and dead branches, and either fall over or snap halfway up the trunk within four years.

For more information on EAB see the video below:



The NPCA manages 41 properties throughout the watershed and most have been impacted by EAB. In some cases, large areas of forest have been heavily impacted by this invasive insect. The NPCA's strategy is to remove ash trees that pose a threat to people and property. That means cutting them down along trails, near infrastructure and in other areas used by people.

NPCA staff assess ash trees in these areas to determine their health and the level of risk they pose. Our practice is to cut down the dead trees and leave them on the forest floor to provide downed woody debris for wildlife and nutrients.

The NPCA is also developing management plans to address situations on our properties where ash trees comprise more than 50% of the forest composition and are in serious decline. The loss of ash trees from a forest where they are the dominant species can result in the complete change in structure and function where the forest will no longer resemble or function (e.g., habitat for forest dependent wildlife species) as a forest.

Intensive forest management techniques maybe required to restore or rehabilitate a forested site impacted by EAB. Coupled with the mortality of ash trees is the introduction of European buckthorn which is an invasive shrub species that is capable of dominating the forest understory. Buckthorn is capable of restricting or limiting the regeneration of native tree species in the understory. If left untreated, a once healthy ash dominant forest will convert to a buckthorn-dominated thicket.

Municipalities throughout the watershed also face costs to remove ash trees in their parks, along city streets and near trails. Private property owners also have to deal with dying ash trees on their own properties. The NPCA does not remove trees on private properties regardless of any environmental designation the property may have.