700 Road Ecological Thinning Project, Cedar River Watershed
Rolf Gersonde, Silviculturist Cedar River Municipal Watershed Seattle Public Utilities – Cedar and Tolt Municipal Watershed Key Features of SPU-HCP (2000)
• Safe and secure water Bull trout supply Common loon • 50-year term
• Ecological reserve Chinook • Restoration commitments – Roads, streams, riparian and upland forests
Spotted owl Forest Restoration Goals
• LSF Conditions – Tree size – Spatially clumped – Foliage height diversity – Decadence • Ecosystem Functions • Biological Diversity • Ecosystem Resilience 700 Rd Project Location in the CRW 700 Road Ecological Thinning Project (2004)
Species: WH, DF, RC, SF, RA Structure: 65 year single cohort, BA 210-360 sqft/ac QMD 9.3” – 14.3” SDI 400 - 620 Stakeholder involvement process Comments at Ecological Thinning Workshop (7/18/2004)
•Prescriptions are too conservative. You should experiment with thinning more heavily. •Prescriptions not conservative enough – they should be limited to never cutting any “big” trees. •You don’t need to experiment. You can learn from what other landowners have done. •Second-growth forests created from clearcutting are on “natural” trajectories and don’t need intervention. •There is more wildlife in my back yard than I have seen in the second growth in the watershed. •You need to create openings to provide habitat diversity and support wildlife. •We need to know exactly how any money made from sale of trees will be used. Stakeholder involvement process Summary of changes
•Reduce area to be ecologically thinned •Reduce number of acres where trees will be yarded •Create numerous variably-shaped small gaps and skips •Create Unit E9 at the top of the ridge •Add variable sized skips around existing unique habitat features •Increase basal area targets •Lower diameter limit for cutting 700 Road Ecological Thinning Project (2006)
Treatments: 230 ac. Thinning with Skips and gaps 120 ac. Cut and Leave Reserve areas Structure type ratio by treatment unit
100% Structure Types 700 Rd Project by Unit
80%
60%
Gaps Trails 40% Skips Thin
20%
0% E1 E2 E3 E4 E5 E6 E7 E8 E9 Scales of Variability Thinning-pool spacing with skips and gaps 700 Rd
Unit E1a Diameter distribution by species
Differentiation into crown and size classes Thinning pool varies by species, create bimodal distribution
80 Pre-thin diam. distribution 70 60 RA 50 NF 40
A SF
TP 30 RC 20 DF 10 WH 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 DBH cl as s Example of thinning prescription (E1) Structural Features
Large skip and gap Thinned matrix Conceptual layout of thinning Unit E6 Effect of canopy density on understory light environment
Stand Visualization System
60
40
20
tRAYci Light Model 0
050100150 Distribution of light intensity at different stand densities
25 BA 327 BA 250 BA 180 20 BA 120 BA 60
15 Frequency 10
5
0 0.0 0.1 0.2 0.3 0.4 0.5 Fraction of above canopy light Wind Disturbance Regime
E2 - Live tree height distribution by DBH 140
120
100 f 80
60 DF 40 RC Ave tree height tree ( Ave WH 20 70:1 line
0 4 6 8 10121416182022242628303234 1" diameter class
Topex: Jean-Claude Ruel, Steve Mitchell, and Naa Lanquaye-Opoku Effect of tree position relative to gap edge on diameter growth and average crown width
40 24
30
20
20
16 10 Average crown diameter (feet) diameter crown Average Diameter increment (mm/10yrs) Diameter increment
12 0 Edge Matrix Edge Matrix
Graph shows median and quartiles, data are taken from mature Douglas-fir stand at CRMW; diameter increments are significantly different at p=0.032; average crown width are significantly different at p=0.0004. Disaggregated growth modeling in FVS
50 ) 40
30 36.1 20 30.0 30.0 24.6 10 Diameter increment (mm/10yrs 0 Aggregated Skip Matrix Edge Down wood volumes:
11% ground cover, 45 tons or 6000 bf/ac on 120 acres 80% of average “westside conifer-hardwood” forests (Ohmann and Waddell 2002) Contractual Issues
Surplus timber production (2.5 mmbf) requires approval from City Counsel (ordinance)
FSC Certification (2006)
Request for Proposal
Long-term relationship with contractors
Operator Certification A&R Cable Thinning Forest Restoration Uncertainties
• Understory response • Effect of CWD on understory developement • Proportion of structure types • Gap size/diversity • Maintaining growth rates • Disturbance interactions