Douglas-fir Bark Beetles

Assessing the impacts of Douglas-fir Bark Beetle infestations in the Cariboo-Chilcotin.

Sponsored by:Ministry of Forests and Range

Steve Baumber, Forest Health Information SpecialistTim Ebata, Forest Health Initiatives Officer

Leo Rankin, Forest Entomologist

The Douglas Fir Beetle is endemic to southern

British Columbia.

Area of Interest

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Forest Coverage in the Williams Lake Study Area (from VEG_COMP_LYR_R1_POLY).

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Hazard Ratings in the Williams Lake Area.

Hazard Rating = A*G*D*Pwhere:A = Age

G = Growth RateD = Tree Diameter

P = Stand Purity

From: A Susceptibility and Risk Rating System for the Douglas-fir Beetle in British Columbia. Draft version 10, April 2001. T.L. Shore and L.

Safranyik. Canadian Forest Service, Pacific Forestry Centre, Victoria, B.C.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Hazard Ratings in the entire study area.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Douglas-fir bark beetle overview survey data for 2007, Williams Lake Study Area.

Problems with Overview Survey Data?• Imprecise.• Easy to miss small infestations.• One pest may be hidden or masked by another: i.e. Douglas-fir bark beetle is thought to be underreported in the past as it was hidden by large amounts of Spruce Budworm.• Hard to diagnose case of death from the air.

Advantages?• Large amount of data collected over the same area in a consistent manner yearly.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Douglas-fir bark beetle overview polygons 2000 – 2009, Williams Lake Study Area.

Trace = 1; Low = 2; Moderate = 3; Severe = 4; Very Severe = 5

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995Trace = 1; Low = 2; Moderate = 3; Severe = 4; Very Severe = 5

Douglas-fir bark beetle overview polygons 2000 – 2009, Chilcotin River Study Area.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Areas with cumulative scores >= 6, Chilcotin River Study Area.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Hazard Class, Chilcotin River Study Area.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Overlay of severe incidence on Hazard Class polygons (derived from continuous forest cover dataset).

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

At Risk Polygons, Chilcotin River Study Area.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Risk Polygons, Williams Lake Study Area.

Hazard Class: VL = 2.5 % Mortality; L = 19% Mortality; M = 49.5% Mortality; H = 83% Mortality.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Risk Polygons, 100 Mile House Study Area (Canoe Creek).

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Forest Composition, 100 Mile House Study Area (Canoe Creek)..

Why?

• It could be the fact that the 100 Mile House TSA has historically seen much more aggressive management for beetles.*

• Or the biogeoclimatic situation in this administrative unit could be fundamentally different, causing Douglas-fir and bark beetle to behave in different ways…

*No source here, just word of mouth!

Biogeoclimatic Zones and Douglas-fir Bark Beetle Infestations..

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Mule Deer Winter Range.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Mature Douglas-fir stands have a thick canopy which shelters deer from heavy snowfalls and provides winter food in the form of needle and branch blow down. After attack by Douglas-fir beetle or other pests the forest can no longer provide these essential functions.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

High Stand Structure Mule Deer Winter Range, Chilcotin River Study Area.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

High Stand Structure Mule Deer Winter Range, 100 Mile Study Area (Canoe Creek).

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

High Stand Structure Mule Deer Winter Range, Williams Lake Study Area.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Old Growth Management Areas, Williams Lake Study Area.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Visual Quality Objective Designated Scenic Areas, Williams Lake Study Area.

Non-timber values at risk:Comparison between study areas

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Average slope of all Douglas-fir polygons.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Average slope of Douglas-fir polygons at risk.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Average elevation of all Douglas-fir polygons.

Source: Ministry of Forests Bark Beetle Management Guidebook, 1995

Average elevation of all Douglas-fir polygons at risk.

Conclusions?

• Everything we see may be the result of lack of treatment (less treatment historically in Willliams Lake TSA, especially on more rugged terrain) -- but this is not necessarily the case.• The bugs could simply prefer the river valleys,• Or their most suitable food source (big old trees) has been left for them in rugged areas such as river valleys) where it also has to serve the needs of Mule Deer and many other ecological and recreational functions.

• Demonstrates the need for more basic research to tackle these problems effectively.