BRAS D’OR BIOSPHERE: The ash trees of the biosphere

In the Mi’kmaw calendar, June is Nipniku’s which translates to “Trees Fully Leafed Time.”

Among the species in the biosphere that are leafing out are the ash trees (in Mi’kmaw: wisqoq). Ash trees provide the usual tree services such as oxygen production, carbon sequestration, topsoil stabilization, and provision of shelter and habitat. In addition, ash trees provide some very special products. My children played baseball with bats made of ash and I store my rock collection in an ash basket proudly made by a Mi’kmaw basket maker.

There are 65 species of ash in the Northern Hemisphere and three are native to the Bras d’Or Lake Biosphere. The green, white and black ash are small to medium deciduous (lose their leaves in winter) trees with stout twigs and deeply furrowed bark. The wood of the white and green ash trees is tough, elastic and straight-grained, making it ideal for products such as axe handles, baseball bats, skis, paddles, oars and many other things. The black ash has been a significant source of wood for basket making. You may be wondering why I have not included the Mountain Ash with the bright, red berries. It actually isn’t a true ash!

- Advertisement -

Ash trees have leaves and stems that are opposite each other (as do maple trees). Ash trees have compound leaves, with several on a stem. The subtle differences in the leaves and the habitat where the tree lives help you identify the type of ash tree that you have found. The most common ash tree in the biosphere is the white variety. The leaves are lighter on the underside which is probably where it got its’ name. The leaves are about 20 to 30 centimetres (cm) long, attached to the main leaf stalk by its own stalk and the leaf scar is U-shaped.

The tree thrives in mixed hardwood forests alongside species such as sugar maple. Tiny petal-less yellow or purple flowers are borne before or at the same time as the leaves in early June and the male and female flowers occur as dense clusters on side buds on different trees. If you want to be sure of your identification, re-visit the tree in the autumn. White ash leaves turn a brilliant orange or red in the autumn whereas other ashes turn yellow.

The white ash trees (in Mi’kmaw: aqamoq) are very significant for it is said that: “It was from four arrows he [Kluscap] shot at four different white ash trees that emerged the Passamaquoddy, Penobscot, Maliseet, and the Mi’kmaq peoples. He then set about teaching them what to eat and what to gather.” (https://www.historymuseum.ca/cmc/exhibitions/aborig/fp/fpz2f21e.shtml).

The Green ash tree is very rare in the biosphere. It is similar to the white ash with compound leaves about 20 to 30 cm long. The wood is similar and is often sold as white ash. However, there are several significant differences between the two species. The white ash has hairy twigs, whereas the twigs of the green ash are smooth. As well as smooth twigs, the mature leaves of the green ash appear to be a similar colour on the top and bottom. As is the case with white ash, flowering occurs with male and female flower clusters developing on different trees. This species commonly inhabits floodplains and wetlands, the land beside rivers (riparian zone) and disturbed areas.

The black ash (in Mi’kmaw: wiskoqey) is a skinny, slow-growing tree which is intolerant of shade and grows well on wet sites along rivers and small brook bottoms or mixed in with alders. The compound leaves are darker on the underside and longer than the other two ash species at 25 to 40 cm. As is the case for the other two species, flowers form before the leaves in early June. However, both sexes can be on the same or on different trees. Black ash is rare and is particularly susceptible to fungal diseases, poor growth and being stunted. Black ash is unique because it does not have fibers connecting the growth rings to each other. This property has made the black ash of great cultural significance to Mi’kmaq for basket making. Pliable wood strips can be separated by pounding with a mallet. Basket makers would crush the weaker spring wood layer and peel off the tougher summer wood in long strips. These were trimmed and used for weaving into baskets.

Our three valued species of ash trees in the Bras d’Or Lake Biosphere are all under threat because of a beautiful little beetle called the emerald ash borer, an invader from Asia that was first discovered in 2002 in Michigan and southwest Ontario. It has been destroying ash forests in Ontario and has spread to Quebec. On May 17, 2018 the Canadian Food Inspection Agency (CFIA) confirmed the presence of emerald ash borer in the City of Edmundston, New Brunswick, the first documented finding for Atlantic Canada. It is on its way to our biosphere! It is the larval stage that causes mortality because it feeds on the inner bark and disrupts water and nutrient flow. Adult emerald ash borers are a dark metallic green colour with tiny bodies (8 millimetres long and 1.5 mm wide), black eyes and flat heads.

This forest pest is monitored by the CFIA under the federal Plant Protection Act, in order to prevent introduction and spread. Monitoring traps have been placed in some ash trees in areas across Nova Scotia, such as Truro. For more information on the emerald ash borer please visit: https://www.youtube.com/watch?v=WAOEaLGm-Ic.

For more information on the regulations, and to report a potential sighting, please contact a local CFIA office or visit the CFIA Web site: http://www.inspection.gc.ca/plants/plant-pests-invasive-species/insects/emerald-ash-borer/eng/1337273882117/1337273975030.

Dr. Annamarie Hatcher is a consulting ecologist and a board member of the Bras d’Or Lake Biosphere Reserve Association. For more information about the Bras d’Or Lake Biosphere Reserve Association, please visit http://blbra.ca/ or check out our Facebook page.