The Waterton Experience
A severe mountain pine beetle attack occured in Waterton Lakes National Park between 1977-1984. Due to the size of the trees and the warm winters the beetles flourished and spread throughout the area. After 1984, with many of the large lodgepole pines dead, the beetle had less food and the cooler winters did them in. Some still survive as a normal part of the environment.
Sofa Mountain in Waterton Lakes National Park - 1982
Throughout the attack and since then, the forest never ceased to look and function like a forest. Twenty-one years after the beetle outbreak, the forest was healthy with a diverse mix of lodgepole pine, spruce, douglas fir and aspen trees. (photo below)
Sofa Mountain - 2003
According to scientific studies, and Ralph Cartar, "During outbreaks, beetles attack trees based on their diameter. They don't use anything less than 10cm dbh (diametre at breast height). They attack 15cm trees at a 10-25% probability, 20 cm trees at a 20-40% probability, 30cm trees at a 30-70% probability, and 40cm trees at a 45-100% probability."
Ralph predicts that about 30% of lodgepoles in Kananaskis will succomb in the outbreak that is coming our way. Once the larger trees are gone the smaller trees, in the understory, enjoy a growth spurt and the forest recovers quickly.
© Canadian Forest Service / Brad Hawkes
The grey trees in this photo, taken along the Waterton Lake shoreline, are dead lodgepole pines
Beetle killed trees are very visible as the needles turn red. When the needles fall off, the grey branches are exposed, as in the photo above. These trees don't absorb much water, but they do hold the snow, shade the snow on the ground and allow snow to evaporate before it melts. All this helps reduce erosion due to snowmelt and also reduces altered high flow cycles, which is important to Calgary's water resources. At the same time, the spruce, fir and small lodgepoles continue to absorb water. If clearcut, none of this water absorption or retention would occur.
Parks Canada policy directs that native insects and diseases are natural ecological processes that should be allowed to proceed without interference if possible. However, the concerns of adjacent land managers must be considered, and where insects or disease pose a serious threat to provincial lands, intervention may occur. They have been cutting and burning affected trees in Banff over the past couple of years.
Red areas show beetle infestation. Black boxes show the locations of the photos below.
Please click an image to see an enlargement.
This is a current (2007) satellite image of the area indicated by the small black outlined box in the centre-right of the map above. That is, Sofa Mountain, the worst affected area. This is what we mean when we say the forest never stops looking and functioning like a forest during and after a beetle infestation.
This is a zoomed out view of the area around the Waterton townsite, indicated in the centre of the map above.
This is an enlarged view of the shore opposite the townsite, indicated by the small inset box on the map. Looks like a pretty healthy forest to me.
