Continuous Forest Habitat
Tree planting season is here which makes it the perfect time to learn more about the importance of trees and forests. A few hundred years ago, large areas of continuous forested habitat covered most of Southern Ontario. This included large areas of forest interior habitat, which is the deep, isolated part of a forest. It’s generally recognized that forest interior habitat starts at least 100 metres from the edge of the forest. Edge habitat includes the part of a forest next to open habitats like meadows and farm fields or human-created breaks like roads and buildings.
In Southern Ontario, forest interior habitat is increasingly rare. Urban and rural development have broken forests into smaller patches with little to no interior habitat. In the Credit River watershed, forest interior habitat represents only about three per cent of the entire area of the watershed.
Forest interior habitat has unique characteristics compared to habitat along the edge.
- It’s less windy since the trees act as windbreaks. This leads to less air pollution from cars or non-native plant seeds getting blown in, like garlic mustard.
- It’s cooler and shadier. This makes it more damp compared to the edge. This is vital to maintain pools of water that wildlife need to live in including aquatic insects.
- It’s quieter since it is further from the sounds of cars and people. This makes it easier for animals to avoid predators, attract a mate and use sound to navigate. For example, calling wood frogs hear each other during breeding and short-tailed shrews make squeaking noises to sense obstacles in their way while moving.
Some wildlife species prefer to use forest interior habitat. Several bird species, like ovenbird and Canada warbler, nest on the forest floor near logs or under shrubs. If they were near the edge, they would be more vulnerable to predators like raccoons that linger there. In addition, northern flying squirrels need large forests to get around. They move by gliding from tree to tree using the loose skin on their bodies, known as patagium, which acts as a parachute. Unlike other squirrels, they are clumsier on the ground causing their movement and home ranges to be more restricted.
Written by CVC’s Christina Kovacs, Natural Heritage Management