here. - Ministry of Forests, Lands and Natural Resource Operations

cr a n B r o o k tSa
Bark Beetles
Mountain pine beetle infestations continued on a declining trend in 2012. Area infested fell by nearly 60%,
from 11,950 hectares to 4,895 hectares, and the proportion of attack classified as moderate or severe fell from
27% to 20%. The number of spot infestations fell by 75% to 345. The most significant declines were seen east
of the Rocky Mountain Trench, with attack levels around the Elk River, Fording River, and Bull River falling
sharply. Red attack was still widespread throughout the St. Mary River, Moyie, and Gold Creek areas. Attack
in whitebark pine increased in the Matthew Creek area, totaling 260 hectares.
Douglas-fir beetle activity remained relatively low in the TSA, with just 136 hectares and fifty spot infestations
of red attack mapped. Most of the beetle activity was in the Elk River area, although several new spot infestations
were noted on the east side of Koocanusa Lake.
Most mortality associated with western balsam bark beetle occurred in small, widely scattered patches. Total
affected area was 790 hectares in 2012.
Defoliators
Western spruce budworm defoliation increased slightly
to 6,980 hectares, all of which was in the Flathead
River area. Defoliation intensity has increased, and over
60% of the affected area was moderately or severely
defoliated. Three-tree beatings performed at permanent
sample plots near Grasmere and Elko were both positive
for western spruce budworm larvae, however defoliation
levels were too low to be detectable from the air.
Results of egg mass sampling conducted in the fall of
2012 indicate that budworm populations and defoliation
intensity will likely decline in 2013.
Aspen serpentine leaf miner was mapped on 1,670
hectares in the St. Mary River and Flathead River areas,
while birch leaf miner damage was limited to 23
hectares.
Foliar Diseases
Larch needle blight infections were fairly widespread in the Flathead River and Wigwam River areas, but scattered
elsewhere. A total of 7,150 hectares were affected, down slightly from 2011 levels of 9,775 hectares. Damage
severity was also down, with less than one quarter of the affected area classified as moderate or severe.
Other damage noted during the aerial surveys was limited to 79 hectares of bear damage. A small area of topkilled
western red cedar was observed in the Teepee Creek area, however no mortality was noted and causal
agent remains undetermined. During ground surveys, Douglas-fir needle cast was noted at several locations
and appeared to be contributing to thinning crowns.
Ministry of Forests, Lands and Natural Resource Operations, Kamloops, B.C.
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Western spruce budworm defoliation in the
Flathead Valley, Cranbrook TSA.