here. - Ministry of Forests, Lands and Natural Resource Operations
here. - Ministry of Forests, Lands and Natural Resource Operations
here. - Ministry of Forests, Lands and Natural Resource Operations
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A Douglas-fir Drought-Decline Complex<br />
During the aerial surveys, tree mortality <strong>of</strong> an unknown cause was detected along the west<br />
side <strong>of</strong> Sugar Lake. Four individual polygons covering 289 hectares were mapped. Followup<br />
ground assessments found a combination <strong>of</strong> Douglas-fir beetle <strong>and</strong> Armillaria root disease,<br />
although drought was likely the catalyst, as not all trees had a biotic causal agent associated with<br />
mortality. The soils in this area are very<br />
coarse, <strong>and</strong> t<strong>here</strong>fore very sensitive to<br />
any water deficits. The st<strong>and</strong>s examined<br />
were mature even-aged Douglasfir<br />
with a minor component <strong>of</strong> western<br />
larch, western red cedar <strong>and</strong> western<br />
hemlock. Douglas-fir <strong>and</strong> western<br />
larch were the most prone to mortality.<br />
Most species, with the exception<br />
<strong>of</strong> western red cedar, have experienced<br />
poor growth over the last several years<br />
as exhibited by the crown symptoms.<br />
It is likely that both Douglas-fir beetle<br />
<strong>and</strong> Armillaria are responding to host<br />
stress; these symptoms may be indicative<br />
<strong>of</strong> changing climatic effects on dry<br />
transitional sites.<br />
A hillside above Sugar Lake showing<br />
symptoms <strong>of</strong> drought/decline, root disease,<br />
<strong>and</strong> Douglas-fir beetle.<br />
Similar but less extensive symptoms have been observed in the Kootenays for the last few<br />
years, most obviously near Trout Lake, w<strong>here</strong> Douglas-fir on dry to mesic sites within the<br />
Interior Cedar-Hemlock zone have displayed thin crowns, dying tops, <strong>and</strong> scattered mortality.<br />
These symptoms have not been detectable from the air but have been observed during other<br />
ground survey work.<br />
Several other minor damaging agents were detected during the aerial surveys. These included<br />
20 hectares <strong>of</strong> cottonwood leaf rust, 24 hectares <strong>of</strong> armillaria root disease, 17 hectares <strong>of</strong><br />
bear damage, 125 hectares <strong>of</strong> birch decline (near Falkl<strong>and</strong>), 82 hectares <strong>of</strong> aspen decline<br />
(near Crater Mountain), 500 hectares <strong>of</strong> wildfire, 70 hectares <strong>of</strong> windthrow, 24 hectares <strong>of</strong><br />
flooding, <strong>and</strong> two l<strong>and</strong>slides that damaged 10 hectares <strong>of</strong> mature timber.<br />
<strong>Ministry</strong> <strong>of</strong> <strong>Forests</strong>, <strong>L<strong>and</strong>s</strong> <strong>and</strong> <strong>Natural</strong> <strong>Resource</strong> <strong>Operations</strong>, Kamloops, B.C.<br />
27<br />
Flooding damage in the Larch<br />
Hills area <strong>of</strong> the Okanagan TSA.