Wednesday, December 16, 2009

Trees of the Boardwalk - Lodgepole Pine 1

Although the lodgepole pine is the most abundant tree species in the Alberta Foothills, it isn't very common around the Beaver Boardwalk. Partly that's because the local soils are very calcareous and pine prefers more acidic soils. Another likely explanation is the history of fires in the area and how pine reproduces. Some people call the lodgepole pine the phoenix tree. Why? Because lodgepole pine requires fire to assit the reproduction process. Like the mythical phoenix a new pine generation rises from the ashes of parent trees scorched by forest fires.

Pine cones contain the secret. Cones take two growing seasons to mature after tiny yellow pollen grains produced by tan-coloured male flowers fertilize the reddish female flowers. Each summer pine and spruce trees produce huge quantities of pollen blown by the wind to female flowers. The excess pollen coats surfaces and forms a yellow film on puddles, and makes some alergy sufferers miserable.

Mature pine cones remain fixed to the parent tree. Cone scales protecting the precious seeds remain tightly locked by a bond of resin, waiting for a fire. It takes a temperature of 45-60°C to melt the resin and release the seeds. Normally that much heat is only produced by a forest fire, which kills the trees but doesn't completely burn the cones. The seeds fall to a cooling and fertile ash bed on the forest floor, where they germinate in incredible numbers.

Pine seeds aren't easily dispersed by the wind or other agents. In nature, fires must usually kill cone-bearing trees to establish a new generation. If there are no pine trees to kill or fires occur infrequently, other tree species replace pine as dominant species in an area.

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