ALDER
The alder tree (all-de-r) is a flowering plant, known as “tupsi” (dup-si) in the Mi’kmaq community. Alder trees can grow as individual trees or in groves; alder groves are called “tupsia’qami” (du-si-aa-hka-mi). Within Nova Scotia, there are two of the three species of alder native to Canada, the Downy Alder and Speckled Alder.
Identification
Alder trees are part of the birch family; they can be a tree or a woody shrub, which can grow up to eight meters tall. Alders are covered in bark that can vary in colour from brown to black and grey, with white spots throughout. The trees are either male or female both with catkins (a downy flowering spike) present in the fall. Females are identifiable by their cone-like catkins while the male catkins are more slender and bunched, with three to five in a cluster. The wind transports the pollen from the male catkins to the female catkins, which then fall in the spring to produce new trees.
The leaves have an oval shape with teeth; they are deep green on the top of the leaves and light green on the bottom. The leaves stay green (they don’t change colour), and fall off in the autumn. Alders have shallow roots that can reach a long distance beneath the surface. When an alder is cut down, shoots appear from their roots systems many meters away from the original tree. Alders can be found growing in areas with poorly drained soil such as abandoned fields, stream banks and some roadside ditches. They are able to grow well in both shade and sun.
To identify the different species of alder use this tree key: https://novascotia.ca/natr/forestry/treeid/trees_of_acadian_forest2.pdf#page=118&zoom=100,0,720
Ecological Importance
Like many trees and shrubs, alders provide habitat and food sources to a range of animals. Moths and butterflies consume both leaves and the catkins; birds consume the seeds. The thick brush provides good cover for nesting sites within the tree and underneath. In the winter the trees provide key food sources for animals such as deer and rabbits, with the larger animals eating the branches and small mammals and birds eating the leftovers.
Alders help stabilize the banks of streams and areas with high erosion with their massive root systems. They are helpful in flood control and in purifying water in waterlogged soils. The nitrogen-fixing bacteria on their roots and their nitrogen rich leaves, when they fall to the ground in autumn, help to enrich the site with nutrients and nitrogen, acting as a fertilizer for other trees and shrubs. They are useful for this purpose in orchards.
Uses
Alders have a lot of traditional uses for medicines and nutrition, since people could make use of different parts of the tree. The catkins were consumed as a source of protein when eaten raw or cooked, but they are very bitter and not very palatable. The fresh bark was used to induce vomiting; it was dried and made into a powder, then also used as a flour or soup thickening agent. When the bark was boiled in a tea, it released an anti-inflammatory substance (like aspirin), and was used to treat skin irritations. Finally, the sap was used a sweetener. It is not currently recommended that we consume alder for medical or nutritional purposes.
Alder wood is still used to create a variety of furniture pieces and tools, and the wood can be used to smoke foods. As it is very durable underwater, it was used historically in foundations that were likely to be wet. Fun Fact: The majority of pillars supporting the canals in Venice were made from alder trees.
Alder bark is rich in tannic acid and has been used in tanning and the dying of fabrics for centuries. Drying the inner back creates a yellow dye, while drying the outer bark creates a red dye, so cotton, silk and wool could be dyed shades of browns, reds, oranges and yellows.
~Emilie Knighton
