EvaluationsEvaluations ofof ImpactsImpacts ofof thethe OkanaganOkanagan MountainMountain ParkPark FireFire onon InIn--streamstream WoodWood andand OtherOther WatershedWatershed ProcessesProcesses

Adam Wei Earth and Environmental Science University of , British Columbia, Canada (Presentation at the Watershed Conference, South Carolina, USA, 2006) TopicsTopics toto bebe coveredcovered

• Rationale for the project • Long-term monitoring approach • Preliminary results RationaleRationale forfor thethe projectproject

• A big picture: forest-water-fish interaction for BC • Disturbance ecology – Wildfire and pine beetle infestation – Emulation of natural disturbance? – Need to know impacts of natural disturbance • In-stream wood (LWD) ecological importance – LWD--morphology—aquatic habitat—fish – Large LWD variability in space and time – Lack of long-term LWD studies There are about 9000 forest fires recorded annually in Canada. An average of 2.1 million hectares are burned every year; virtually all of it is boreal forest. On average, 2000 occurred each year, 50% by man and 50% by lighting Total Area Affected by Mountain Pine Beetle in Western Canada 2001: Mountain pine beetle damage LWD as cover, Salmon Arm fire, 1998 Channel morphology, 90 years after fire, Upper cr. LWDLWD rolerole && managementmanagement paradigmparadigm

• Aquatic environment – Channel morphology & fish habitat – Diversity of hydraulic flows – Sediment trapping – Nutrients & its long-term release – Bank erosion prevention – Paradigm shift: LWD clean-up – LWD protection--?? LWD loading

Pulse

Fire

20 100 yr A theoretical LWD pulse and dynamics over an average fire interval in lodgepole pine forests, BC interior (a) UNDISTURBED RIPARIAN FOREST INTENSIVE TREE/SNAG REMOVAL ACCELERATED SNAG FAILURE NORMAL SNAG FAILURE

?

RIPARIAN CWD RECRUITMENT RIPARIAN CWD 0

t 0 t 1 t 2 t 3 TIME

(b)

UNDISTURBED RIPARIAN FOREST INTENSIVE TREE/SNAG REMOVAL NATURAL DISTURBANCE

? IN-STREAM CWDLOAD

0

t 0 t 1 t 2 t 3 TIME

Generalized models of LWD loads & recruitment for small streams (Bragg 2000) G Okanagan Mountain Park Fire Summer, 2003 www.castanet.net www.castanet.net

A unique opportunity for long-term monitoring

Interior Douglas-fir biogeoclimatic zone Long-term Monitoring Approach: 3 fire sites and 3 control sites FieldField methodsmethods (1)(1)

• Six sites (3 fire & 3 old growth / control sites) • A 100m length of reach for each site • LWD (D > 10cm and L > 1m) • All LWD pieces were tagged • For each LWD piece, decay state, orientation, position, stability, input source and function were documented FieldField methodsmethods (2)(2)

• LWD locations (coordinates and elevation) were recorded using the total station Goody Creek, Okanagan Mountain Park

CalculationsCalculations (1)(1)

• LWD recruitment (input) - all new pieces appeared in the study reach in the next year’s survey • LWD output – all pieces with the tag number were disappeared in the next year’s survey CalculationsCalculations (2)(2)

• The centroid of each LWD was calculated based on the X coordinate and Y coordinate of the piece • The difference of the centroid location of the same LWD in the two years’ surveys was recognized as the movement of the piece. PreliminaryPreliminary results:results: annualannual inputinput andand outputoutput ofof LWDLWD

Site Site LWD Output LWD Input Output Input name type Number (1) Volume Number (2) LWD LWD Volume 3 3 (piece) ) (m ) (piece) (piece) (piece) (m Bellevue Fire 24 32 8 0 1.26 0

Deeper Fire 41 42 2 1 0.132 0.017

Goode Fire 41 44 4 1 0.3814 0.009

Greata Control 58 55 4 7 0.0734 0.131

Jack Control 23 25 3 1 0.1983 0.011

McDougall Control 87 82 0 5 0 0.312

PreliminaryPreliminary results:results: transporttransport ofof LWDLWD

Site Site Total Moved % Longest Mean name type piece piece Distance moved (m) distance (m)

Bellevue Fire 24 4 16.7 56.7 31.3

Deeper Fire 41 5 12.2 32.5 20.4

Goode Fire 41 4 9.8 13.0 9.6

Greata Control 58 13 22.4 23.8 16.1

Jack Control 23 4 17.4 26.3 17.6

McDougall Control 87 11 12.6 20.9 12.7

NothingNothing concluded,concluded, justjust observationsobservations

• On average, LWD loading is increased in the fired sites while it is in the relatively balanced condition in the control sites • About 10-20% of wood pieces were transported, with the 10-20 m distances • There were no large LWD fluxes immediately after fires Research Program at UBC Okanagna: Disturbance & Watershed Processes

Research Group PartnersPartners

UBC Ministries Forest Industries (Riverside, Gorman Bros.) Consulting (Dobson Engineering) FORREX OtherOther topicstopics relatedrelated toto thethe firefire ::

• Effects on hydrology and water Quality Jeff Curtis & Adam Wei (long-term monitoring) • Effects on soil repellence and erosion David Scott (3 years or longer)

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