What comes to mind when you think about pollinators? Flowering meadows and monarchs? Honey from the European honey bee? What about wind-pollinated trees that both feed native bees and host a myriad of caterpillar species that feed the birds?
Recently, the Xerces Society spent the day with Natural Resource Conservation Service, UNH Extension, and Licensed Forester/Forest Ecologist Charlie Moreno to talk about forestry through a native pollinator lens during a tour of Branch Hill Farm.
Branch Hill Farm is located near the Salmon Falls River on the New Hampshire-Maine state line in Milton Mills, NH. Its nearly 3,500 acres are conserved by an endowment from the Carl Siemon Family Charitable Trust. Much of the land is forested along with riparian areas, wetlands, and feathered forest edges that open to fields managed for both wildlife and hay production. Branch Hill Farm has a small, diverse vegetable operation that feeds 40 families. Starting in 2020, Executive Director Jared Kane planted the Preservation Orchard at Branch Hill Farm to conserve the unique genetics of 100+ varieties of apples and pears, with a goal to expand to 400 varieties!
Managing trees creates a haven for forest pollinators
Branch Hill Farm is home to wildlife of all shapes and sizes – bats, grassland birds, turtles, fish, turkey, and deer to name a few – but on our tour we focused on pollinators. From the tiny specialist native bees visiting native understory plants, to the generalist bumbles foraging all seasons long, to the sweat bees that nest both beneath the soil and high up inside dead tree branches.
When Moreno first arrived on the scene, much of the forest was overgrown by beech trees that were suppressing the natural diversity of trees, shrubs and understory spring ephemeral flowers that feed specialist pollinators. To remedy that, they implemented EQIP practices to tenaciously manage up to 1 acre of the forest mechanically by hand each day. They have successfully reduced beech overgrowth in much of the forest, which promotes diverse pollinator habitat.
Moreno’s face lights up as he talks about the progress they’ve made. To maintain a mixed age forest, the landowner’s overarching forestry goal, with Moreno’s help, is to cut about one-fifteenth of the acreage every 15 years to promote wildlife and forest health.
Wind-pollinated trees are a key food source for invertebrates
During the tour, we walked through yellow birch, red maple, white oak, black birch, pine, and hemlock with understory plants like blueberry and lady slipper. Some of the oldest trees reaching the canopy are estimated to be 160 years old, while some of the youngest acorns are sprouting seedlings beneath; 2017 and 2020 were good acorn years.
Oak, surprisingly to most people, is one of the unsung heroes of pollinator trees. Over 500 species of beloved butterflies and moths rely on oak as caterpillars (Tallamy and Shropshire 2009). Some of these caterpillars will transform into adult moths and butterflies, while many will be consumed by birds and predatory wasps. Despite oak being wind pollinated, its protein-rich pollen also feeds many species of native bees. But oaks aren’t just a wind-pollinated anomaly – other wind-pollinated trees like ash, walnut, birch, and beech provide pollen for native bees. Xerces staff Kass Urban-Mead shared that the average sugar maple tree makes 100 billion pollen grains and is important for helping feed bees when they emerge in spring!
Don’t miss the forest for the meadows
With recent research highlighting the importance of bee habitat and caterpillar use within forests and on feathered edges, we encourage landowners with forested landscapes to think beyond planting the classic prairie-style meadows that are more suited to open land. Instead, in wooded areas we advocate for managing what is already there by releasing remnant tree, shrub, and understory plants that provide valuable habitat for pollinators. Different trees, understory forbs, and shrubs are preferred by different species of bees and butterflies, so managing for healthy, diverse forests with multiple stand ages is a great way to support pollinators. And don’t forget to leave snags and dead fallen wood to give a leg up to native bees and other invertebrates!
If you’re interested in pursuing a Forest Management Plan for wildlife, reach out to your local USDA Natural Resources Conservation Service field office to start the conversation and potentially receive funding towards your conservation efforts.
To learn more about forestry for pollinators, join us for a free Xerces Webinar “Pollinators in the woods? The place of wild bees in a changing forested landscape” lead by Kass Urban-Mead on January 26, 2023 at 10 AM - 11:00 PST, or catch the recorded version on our prolific Xerces Youtube Channel.
To learn more about oaks and their critical role in wildlife conservation, consider reading Doug Tallamy’s book The Nature of Oaks or the following two white papers that highlight the role of native woody plants in pollinator conservation:
- Tallamy, Douglas W, and Kimberley J Shropshire. “Ranking lepidopteran use of native versus introduced plants.” Conservation biology: the journal of the Society for Conservation Biology vol. 23,4 (2009): 941-7. doi:10.1111/j.1523-1739.2009.01202.x
- Katherine R. Urban-Mead, et al. "Bees In the Trees: Diverse Spring Fauna In Temperate Forest Edge Canopies." Forest ecology and management, v. 482 ,. pp. 118903. doi: 10.1016/j.foreco.2020.118903