Trees of the boreal forest

The balsam fir is well known as a popular Christmas tree species. It is the main coniferous species browsed (eaten) by moose. When overbrowsed, balsam fir saplings will produce an excess of buds, distorting their usual conical shape into a thick sphere shape. Balsam fir are also the most susceptible species of tree to infestations of spruce budworm, despite the name of the insect.

How to identify:

• Balsam fir trees average about 18 m in height, being a small to medium-sized conifer, and taper to a thin point at the top.
• Needles are flat and opposite. The top of the needle is a dark, shiny green, while the bottom has two thin, white stripes.
• Bark is gray, and appears smooth and waxy. It will often have blisters filled with sap, especially when the tree is young.
• Cones are barrel shaped, and grow upright and erect. When ripe, the seeds fall off the cone, leaving the center of the cone still attached to the branch.

The white birch is a deciduous tree species most easily recognized by its thin, white bark that peels off into large sheets. White birch trees are browsed (eaten) frequently by moose. In response to browsing, this species will send up multiple new stems, creating a warped, stunted appearance unlike that of a healthy birch tree. White birch trees are one of the first species to regenerate in an area after a forest disturbance.

How to identify:

• White birch trees are most easily identified by their white, paper-like bark. 
• It is a medium-sized tree averaging 16 m in height. 
• Leaves alternate and are described as oval-shaped or triangular-shaped, with serrated edges. 
• Long, soft flowers called ‘catkins’ hang downwards from branches.

The white spruce is a large coniferous tree that receives its name from the white powdery coating on its needles. This species is rarely eaten by moose, but is affected by outbreaks of spruce budworm. As a component of the Bring Back the Boreal project, park staff and volunteers have been planting white spruce seedlings to help restore forest health. Since these seedlings won’t be overbrowsed by moose, they will grow to provide important food and shelter for boreal animal species.

How to identify:

• White spruce trees are one of the largest trees in the boreal forest, averaging 24 m in height. They commonly grow in old farm fields and other clearings. 
• Needles are stiff, four-sided, and needle-like, and are blueish green in colour with a white powdery coating. The needles form a spiral arrangement around each twig of the tree, standing out in all directions. 
• The bark is a smooth, light gray when the tree is young, and gradually becomes scaly and dark gray or brown as it matures. 
• Cones are narrow and cylindrical and fall off the tree before dispersing their seeds.

Many of the key features of white spruce trees are similar to those of black spruce trees. To tell the difference between the two species, look for:

• Colour of needles – white spruce needles have a blue tint, while black spruce needles are green. 
• Twigs – white spruce twigs are smooth, while black spruce twigs are covered in small hairs, making them look fuzzy 
• Shape – white spruce trees are full and conical in shape; black spruce trees are narrower with branches that droop. 
• Cones – white spruce cones are narrow and cylindrical, whereas black spruce cones are smaller and egg-shaped. 
• Smell – when crushed, white spruce needles smell pungent, while black spruce needles give off a sweet aroma.

The black spruce is one of the smaller, slow-growing trees in the boreal forest, but is able to adapt and survive in poor environments. It is also known to be a very strong tree. This species is seldom eaten by moose and spruce budworm.

How to identify:

• Black spruce trees average at 5 m in height, as a small and narrow conifer species. 
• Needles are stiff, four-sided, and green, forming a spiral arrangement around each twig of the tree, standing out in all directions. 
• The bark of a black spruce tree is scaly and is dark gray or brown in colour. 
• Cones are small and egg-shaped. 
• They are commonly found in swamps and wet areas.

Many of the key features of black spruce trees are similar to those of white spruce trees. To tell the difference between the two species, look for:

• Colour of needles – black spruce needles are green, while white spruce needles have a blue tint. 
• Twigs – black spruce twigs are covered in small hairs, making them look fuzzy, while white spruce twigs are smooth 
• Shape – black spruce trees are narrow with branches that droop, white spruce trees are full and conical in shape. 
• Cones – black spruce cones are small and egg-shaped, whereas white spruce cones are narrow and cylindrical. 
• Smell – when crushed, black spruce needles give off a sweet aroma, while white spruce needles smell pungent.

The American mountain ash is not a true ash tree, despite its name. It appears in the form of a small deciduous tree or shrub, and is easily distinguished by its white flowers or red berries, depending on the time of year. American mountain ash is a preferred browse species for moose, and is also favoured by many types of birds and small mammals.

How to identify:

• American mountain ash trees average about 10 m in height, and may appear as a shrub or small tree.
• Leaves are opposite with toothed edges, and grow on slender branches.
• From May-June, round, flat-topped clusters of white flowers appear, which are replaced in late summer by orange or red berrylike fruits that last into the winter.
• Bark is gray or brown in colour with a smooth texture that may develop cracks or splits as it matures.