See the Forest for the Bees

Two people standing in a forest looking up at trees

Planting Trees Can Support Bees That Rely on Forests To Survive

During the 1850s, nearly 70 per cent of the Credit River Watershed was covered by forest. By the turn of the century, widespread clearcutting had dropped that number to below 10 per cent. The rapid decline in forest cover was not unique to Ontario but consistent across North America as European settlers and the practice of agriculture spread across the continent. That these areas were once covered in forest piqued the interest of several American scientists interested in bee habitat. They wondered: if forest was previously the dominant habitat type, shouldn’t there also be forest-associated bee species?

It’s easy to associate bees with sunny, wide open spaces like gardens and meadows since that’s where they’re more visible. But scientists Tina Harrison and Colleen Smith have shown that about a third of native bee species are reliant on forest habitat.

Sweat bees show behaviours that suggest they’re forest specialists. Green metallic sweat bee courtesy Christina Butler.

These forest-associated species are solitary, spring-flying bees with short periods of adult activity. Their behaviours match the seasonal cycles of deciduous forests. They emerge in March or April to catch the early bloom of spring ephemeral wildflowers, trees and shrubs, and disappear around June when these blooms fade. In contrast, bee species relying on agricultural and urban landscapes tend to emerge later in the season and fly for longer.

The early spring activity of native forest-associated bees is not just important for native woodland plants, but also for the commercial fruit industry. Non-native honeybees, which are most often raised and associated with agricultural pollination, have been found to be less active in the cold, early spring when apple and cherry trees are in bloom. Supporting native forest-associated bees, rather than just honeybees, can therefore benefit agricultural production and spring ephemeral plant pollination.

Enhance Your Forests for the Bees

Forest-associated bees are more likely to be found in large (rather than small) tracts of forest. Planting more trees to expand existing stands can increase habitat and support larger populations. Enhancing biodiversity in your woodlands with early-blooming trees, shrubs and wildflowers will also provide these species with the food they need to survive. This is crucial as many common garden pollinator plants bloom later in the season when forest-associated bees are less active. Connect with a stewardship coordinator to learn how we can help.

Your Countryside Stewardship Team

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