2013 Silver Fire Treatment Effectiveness Monitoring Results Year Three
Mike Natharius Forest Soil Scientist/BAER Coordinator Gila National Forest
SER Southwest Conference
November 20, 2015 Tucson, AZ
2013 Silver Fire • 138,000 acre fire, lighting strike, June 7th - July 15th, 80% contained • 21,000 acres high severity, 37,000 moderate severity, 81,000 low
and unburned • Aerial seeded 13,000 acres of high severity burn in mixed conifer
and pine type, seeded with annual barley and small percent of native grass seed
• Aerial mulched 2,900 acres of the seeded acres • Values at Risk • two communities below burn adjacent to Percha Creek, State
Highway 152, many old mines in several of the watersheds, potential contamination of community drinking water sources, FS campgrounds, trails and roads
• Soil productivity and basic watershed function
Silver Fire Monitoring Objectives Evaluate treatments of seeding and mulching/seeding vs no treatment on: Canopy and vegetative ground cover Maintenance of site/soil productivity Effects on natural recovery, species richness, and long term site
recovery Regeneration of fire adapted woody species (tree/shrubs) Effectiveness of treatments on steep slopes of 40 to 60 percent Sites to be monitored annually for 3 years
Study Design • Two forest types pre- fire
– Mixed conifer – High elevation or northerly facing slopes – Pine – Lower elevations or southerly facing slopes
• Three plots established in each forest type and each of the treatment types, all plots located in high severity burn areas – Three 100 ft transects/plot, line-point intercept method used for
percent canopy cover and ground cover components of: basal area, litter, moss, rock & bare soil
– One tenth acre ocular canopy cover plot – to determine cover of plant species not detected or encountered by line-point intercept transects
– Line gap intercept transects for measuring canopy cover of regenerating shrubs and trees
• First years data collected in October - December, 2013 • Second years data collected September – November, 2014 • Third years data collected September – November, 2015
Permanent monitoring plot locations Tried to achieve good distribution of plots throughout burned area and treatment types Trails used to access plots which somewhat limited plot locations Elevations of monitoring plots ranged from 7,200 to 9,600 ft.
Burn Severity Map of Southern Portion of Silver Fire Severity
Mixed Conifer Seeded Plots Year One
Mixed Conifer Seeded Plot #1 Mixed Conifer Seeded Plot #3
Mixed Conifer Seeded/Mulched Plots Year One
Mixed Conifer Seeded/Mulched Plot #2 Mixed Conifer Seeded/Mulched Plot #1
Mixed Conifer Non Treated Plot Year One
Mixed Conifer Non Treated Plot #3 Pedestaled rock, approximately 3 inches of soil loss
Pine Seeded Plots Year 1
Pine Seeded Plot #1 Pine Seeded Plot #3
Pine Seeded/Mulched Plots Year 1
Pine Seeded/Mulched Plot #2 Pine Seeded/Mulched plot #1
Pine Non-Treated Plot Year 1
Pine Non-Treated Plot #1 4 Inches of Soil Loss
Barley Establishment on Seeded Site
September 4th, 40 days after completion of aerial seeding operations
August 6th, 11 days after completion of aerial seeding operations
Barley was established and providing for watershed protection during a portion of the 2013 monsoon season
Mean Canopy Cover Percentages Year One 2013
p=0.001
Canopy cover was very effective in reducing raindrop impact and subsequent soil detachment and off site soil movement
Mixed Conifer Seeded Plot Year Two and Three
2014 2015
Mixed Conifer Seeded/Mulched Plot Year Two and Three
2014 2015
Mixed Conifer Non-Treated Plot Year Two and Three
2014 2015
Pine Seeded Site Year Two and Three
2014 2015
Pine Site Seeded/Mulched Year Two and Three
2014 2015
Pine Non-Treated Site Year Two and Three
2014 2015
Treated areas had a significant amount more litter and a significant amount less bare soil vs the non-treated areas in 2014
The annual barley planted in 2013 provided for exceptional ground cover in 2014.
Mean Ground Cover Percentages 2014
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Seeded Seede/mulched Non-Treated
Litter
Bare Soil
Treatment Seeded Seeded/Mulched Non-Treated Litter 39% 47% 4% Bare Soil 5% 5% 41%
% Litter and Bare Soil
Effects of treatments on species richness and natural recovery
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5
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Seeded Seed/Mulch Non-Treated
201320142015
Mean Species Count By Treatment Type
species count
Sediment Production on Seeded vs Non-Seeded Plots on the 2014 Signal Fire, Gila National Forest
• First and second years figures for erosion rates generated from seeded vs non-treated plots on the Signal Fire, Nori Koehler, Micah Kiesow
2014 2015 • 1 (treated) – 15 tons/ac • 2 (treated) – 16 tons/ ac • 3 (untreated) – 38 tons/ac • *4 (untreated) – 20 tons/ac
*Trap was breached and sediment was lost to over topping.
• 1 (treated) – 0.7 tons/ac • 2 (treated) – 0.5tons/ ac • 3 (untreated) – 7 tons/ac • 4 (untreated) – 5 tons/ac
Conclusions
• Seeding with annual barley was very effective in increasing canopy cover the first month after seeding
• Seeding with annual barley was effective the first year in assisting to maintain soil/site productivity (resilience) by reducing erosion and sedimentation
• The barley grown in 2013 provided for exceptional ground cover in the form of litter in 2014, reducing erosion on those sites in year two
• Visual observations indicate those areas not treated experienced much higher rates of erosion than the treated areas
• Cost Benefit 85-100 dollars /acre to seed, keeps 25-30 tons/acre on site • At the end of year three it appears that treatments have had little to no affect
on species richness or natural recovery • Treatments appear to have no affect on regeneration or growth of fire
adapted woody species • Treatments were effective on steep slopes of 40 to 60 percent
Aspen Colonization By Seed
Seeded mixed conifer site that pre-fire had no aspen present, 2015 Seeded pine site that pre-fire had no aspen present, 2015
Seeded/Mulched site that pre-fire had no aspen present, 2014
• Spring of 2014 there was an aspen bloom up to 8 miles away from some of these sites
• Aspen establishment on three conifer treated sites and two no treatment sites
• Aspen establishment on 1 pine seeded site and 1 pine non-treated site
