Ensuring a future for American beech trees

Kejimkujik National Park and National Historic Site

Parks Canada is cultivating a seed orchard of disease-resistant American beech trees at Kejimkujik National Park and National Historic Site.

American beech trees

American beech trees (Fagus grandifolia) are a hallmark of Nova Scotia’s Wabanaki-Acadian forest. The shade-tolerant hardwood trees can live for centuries.

Healthy beech trees have smooth trunks and ridged, oval-shaped leaves.

The trees’ nuts are a food source for black bears, deer, raccoons, chipmunks, squirrels and birds.

Beech trees range from as far east as Cape Breton to southern Ontario, extending southward throughout the eastern United States.

A species under threat

Today’s American beech trees face numerous threats, ranging from beech bark disease (BBD) to beech leaf disease (BLD) to the invasive beech leaf-mining weevil.

Beech bark disease

Beech bark disease—a combined insect-fungal infection—affects most beech trees in Nova Scotia. It leaves cankers on the trees’ bark and causes the trees to lose water and nutrients. Eventually, it kills the trees.

Beech bark disease is caused by an infestation of beech scale, a small, invasive insect which punctures the bark of beech trees, leaving openings for native fungal pathogens to infect the tree. Between 50 to 85% of infected beech trees will die within 10 years of infestation.

Beech scale

The beech scale was introduced in North America in the 1890s, first appearing in the Halifax Public Gardens. The disease has since spread throughout beech tree populations in eastern Canada and the U.S.

Beech leaf-mining weevil

The beech leaf-mining weevil is a more recent threat to American beech trees. Native to Europe, the beetle-like insect ranges from 2 to 3 millimetres in length and feeds on the leaves of American and European beech trees. The weevil was first discovered in Halifax in 2012 and spread soon afterwards to parts of Cape Breton and the Annapolis Valley. Since then, it has spread to PEI and New Brunswick.

Beech leaf disease

Beech leaf disease is a foliar disease caused by an infestation of the invasive nematode. The worm-like, parasitic insects feed on beech buds and leaves, yellowing and deforming them. Young trees die from the disease. While BLD is present in Ontario and parts of the U.S., it has not yet been found in Nova Scotia.

Hope for the beech tree

In the face of these threats, some American beech trees have shown signs of resilience.

Cultivating a disease-resistant seed orchard

In partnership with the Canadian Forest Service, Parks Canada has been cultivating a seed orchard of beech bark disease-resistant trees at Kejimkujik National Park and National Historic Site.

The initiative started in 2010. The Canadian Forest Service spearheaded a project to collect grafts from American beech trees that showed signs of genetic resistance to BBD. Researchers collected grafts from trees around Halifax to form new, BBD-resistant beech trees. Each seedling contained upwards of nine different genotypes. Kejimkujik was selected as one of three Parks Canada-administered sites to plant an orchard of the new BBD-resistant saplings, along with Fundy National Park and PEI National Park.

The aim of the orchards is to produce and harvest enough seeds that, in time, American beech trees can help repopulate eastern Canada’s hardwood forests. In 2025, Parks Canada harvested 300 beech seeds from Kejimkujik’s beech tree orchard. The seeds were sent to the National Tree Seed Centre in Fredericton, New Brunswick, for long-term storage.

Despite the serious challenges of beech leaf disease and beech leaf-mining weevil, scientists hope that one day these seeds will return healthy American beech trees to the Wabanaki-Acadian forest.