Watershed Research Summary
Rennell Sound Experimental Cutblocks
Tom Millard and Bill Floyd
▼
Introduction
Watershed Location Data
T
wo cutblocks located in Rennell Sound on the west
Haida Gwaii (Queen
coast of Graham Island
Location (descriptive)
Charlotte Islands)
in Haida Gwaii were
subjected to different
Location (geographic)
53°25’N 132°30’W
This project evaluated
harvesting methods to
Coastal Western Hemlock
evaluate whether alternative
whether alternative
Very Wet Hypermaritime
harvesting methods could
harvesting methods
Central variant (vh2);
Biogeoclimatic zone(s)
be effectively and safely
Mountain Hemlock Wet
could be effectively and
applied in steep, marginally
Hypermaritime Windward
safely applied to steep,
variant (wh1)
stable terrain. Planning
marginally stable terrain
for the cutblocks began
Elevation range
20–660 m
in 1990 in response to
on the west coast of
concerns regarding postHaida Gwaii.
Precipitation (mean annual)
3000–4500 mm
logging landslides affecting
fish habitat. The cutblocks
were logged in 1992 with
some of the earliest single tree, helicopter-yarded harvesting after logging and then after significant precipitation events
in coastal forests. Post-logging monitoring for landslides,
have occurred. Two climate stations (one low elevation, one
soil disturbance, and windthrow was done immediately
high elevation) are monitored.
Rennell Sound Experimental Cutblocks
Gregory Creek
Cutblock
British
Columbia
Hangover Creek
Cutblock
★
FC 6 □
FC 7 □
□ FC 1
FC 8 □
FC 10 □
□ FC 19
FC 10 □
FC 11 □
50%
Group
Selection
Clearcut
6.4 ha
6.8 ha
FC 12 □
FC 13 □
Conventional
18.2 ha
25% Group
Selection
6.4 ha
□ FC 17
□ FC 16
25% Single □ FC 15
Tree Selection
7.5 ha
□ FC 14
0
20
FC 11 □
□ FC 18
Control
34.7 ha
FC 5 □
100
250
metres
FC 16 □
FC 12 □
FC 13 □
FC 15 FC□14
□
FC 9
□
50% Group
Selection
8.3 ha
FC 4
□
25% Single □ FC 98
Tree Selection
9.7 ha
□ FC 97
25% Group
Selection
9.3 ha
□ FC 29
□ FC 28
□ FC 27
Clearcut
8.5 ha
Control
□
9.6 ha
FC 17
FC 18 □
□
□
FC 19
□
FC 20
Falling boundary
FC 21
□ Falling corner
□
FC 22
Treatment boundary
Road
□ FC 1
FC 3 □ FC 2
□
□ FC 99
□
FC 26
□ FC 25
□ FC 24
□
FC 23
0
100
metres
250
Streamline Watershed Management Bulletin Vol. 14/No. 1 Fall 2010
Watershed Research Summary: Rennell Sound Experimental Cutblocks (continued)
Research Design
Study type
Case study with treatments
Treatments
Helicopter-yarded: clearcut,
50% group (patch) selection,
25% group (patch) selection,
25% single tree selection.
Cable-yarded clearcut
Controls
Unlogged
Study duration
1990 to present
Pre-treatment measurement
period
start: 1990
end: 1992
Post-treatment measurement start: 1992
end: Ongoing
period
Parameters measured
Landslides, soil disturbance,
windthrow, precipitation
Results
• Post-harvest soil disturbance increased by 22%
compared to pre-existing soil disturbance.
• The majority of soil disturbance (including landslides)
occurred within the first 3 years post-harvest.
• Landslides continue on an episodic basis in response to
large storms.
• Grapple yarding resulted in much higher soil
disturbance than heli-yarding.
Streamline Watershed Management Bulletin Vol. 14/No. 1 Fall 2010
• Single tree selection and helicopter-yarding in coastal
forests is possible,and the results of this project have
lead to their common use.
• Windthrow is more of an issue in group selection areas
than single-tree selection areas.
References
▼
Krag, R. 1997. Summary of Rennell Sound helicopter logging trials.
Queen Charlotte City, B.C.
Krag, R. 1998. Productivities, costs, and site and stand impacts of
helicopter-logging in clearcuts, patch cuts, and single-tree
selection cuts: Rennell Sound trials. In: Carnation Creek and
Queen Charlotte Islands Fish/Forestry Workshop: Applying 20
years of coast research to management solutions. D.L. Hogan,
P.J. Tschaplinski, and S. Chatwin (editors). B.C. Ministry of
Forests, Victoria, B.C. Land Management Handbook No. 41,
pp. 201–214.
Millard, T. and S. Chatwin. 2001. Using helicopter harvesting on
steep slopes to reduce erosion, preliminary results: Case study
on Queen Charlotte Islands, British Columbia. B.C. Ministry
of Forests, Vancouver Forest Region, Nanaimo, B.C. Extension
Note No. 010. http://www.for.gov.bc.ca/rco/research/
Geompub.htm
Contact Information for Project Leader(s)
▼
Tom Millard
B.C. Ministry of Forests and Range, Nanaimo, B.C.
Email: [email protected]
Bill Floyd
B.C. Ministry of Forests and Range, Nanaimo, B.C.
Email: [email protected]
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