Wednesday, January 13, 2010

Trees of the Boardwalk - black spruce 1

Two of the three local spruce species are found at the Beaver Boardwalk. Unfortunately you can't tell black spruce and white spruce apart by their colour namesakes. The 3rd species, Engelmann spruce, is only located at higher elevations near treeline in our area.  Black spruce is the smallest local species. The biggest local specimens seldom exceed about 40 cm in diameter and 20 m in height. Although black spruce will grow in a wide range of soil conditions, it's most abundant on organic wetland soils. However in eastern Canada black spruce is associated with mineral soils in upland areas.

The best way to tell the difference between black spruce and white spruce is by looking at the cones. Both species have smooth, sometimes pitchy, cones. The longer white spruce cones open as they mature and tiny winged seeds spill from the open cones to be blown where the wind takes them. In contrast, black spruce cones are smaller and rounder. And while they may open while still on the tree like white spruce, they often remain closed for years, waiting for a hot sunny day or a forest fire to open the cones and spill the seeds.

Boardwalk users may have noticed a dark brown stain on the edges of the decking in a few places. The stain came from black spruce cones schucked by red squirrels on the edge of the structure. Rain soaked the discarded cone scales leaked the dark stain. It will be interesting to see how long that stain lasts!

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