Forestry Friday: Why Bees Need Forests Too

Did you know that our forests provide important habitat for bees and other pollinators?  At a recent forestry meeting, Forest Society foresters learned all about this topic from Kass Urban-Mead of the Xerces Society.   While we often think of bees as only utilizing flowers in our gardens or fields, our forests provide critical habitat features to these important pollinators. 

A new study estimates that one-third of our native bees in the northeast are forest specialists, taking advantage of the nectar and pollen produced by trees and spring ephemerals in the forest understory.  Another third are specialists to open habitats such as fields and meadows, and the final third are generalists, using both types of habitat. 

Did you know that there are nearly 4,000 species of native bees in North America and over 20,000 species worldwide? Bumble bees are probably our most well-known social native bee, and some will overwinter and nest in leaf litter on forest floors, as well as collect forest pollen.

Most native species are solitary bees, where only a single female bee takes care of a nest, and is only active for only 4-6 weeks each year. Solitary bees emerge as adults, create a nest (commonly in cavities, soil, or dead wood), and must collect enough pollen to feed the next generation of bees in the few weeks before they die. They lay eggs on the pollen they collect, which hatch, eat the pollen, and then overwinter (often as pupae).

Many species have only one generation each year, so the offspring won’t emerge until the same time the next year.  Many of our forest-associated species are active in spring, when canopy trees are blooming and light can easily reach the forest floor.

Because solitary bees have short flight periods, they sometimes specialize on plants that bloom during their adult lives. Many forest-associated solitary bees are active in spring and specialize on spring ephemeral flowers.  For example, the trout-lily mining bee almost exclusively feeds its young on trout lily pollen!

Sustainable management of our forests for health and diversity can benefit many species of wildlife, including bees and other pollinators!