Aspen and Oak Community Response to Restoration Bobette Jones Coye Burnett
Shade intolerant Aspen Life History Clonal: relies on vegetative reproduction between episodic seeding event Disturbance dependent: releases apical dominance/ creates establishment sites for seeds
Ecological Importance Landscape heterogeneity Biodiversity: Abundance and diversity of plants, birds, and inverts are greater in aspen stands than surrounding conifers Provide: higher forage quality as well important habitat structure for birds and mammals Water yields: aspen communities have less intercept and a lower duration of transpiration compared to conifer communities
Kuhn et al. 2007 associated aspen-meadow-conifer forest sites. Aspen with <20% conifer cover. 2.5 a (1.54) a (1.63) Shannon-Weiner Diversity 2.0 1.5 1.0 0.5 0.0 b (0.64) Aspen Conifer Meadow Community Type p < 0.0001
Baseline monitoring Risk Rating Summary, Live Stands Only (2000-2011, N=700 stands; 3,805 acres) Stands 17% Mod 40% High 4% Low 39% High+ Risk Factors % Conifer encroachment 96 Excessive browse 54
Treatments Mechanical Thinning Aspen regeneration Soil moisture Stream attributes Fencing Aspen regeneration Grazing strategies
Results Effect of conifer removal on aspen density 4000 3000 departure from control aspen number 2000 1000 0 0 1 2 3 4 post treatment year None (Tot) Cut (Tot) None (SC1) Cut (SC1) None (SC2) Cut (SC2) None (SC3) Cut (SC3)
Results
Results
Results No adverse impact to in-stream or riparian habitat detected Collaborative Project (UCD) >60% of samples <0.05 ppm for NO 3 -N, NH 4 -N, PO 4 -P. Mean TSS < 15 ppm. No significant change in stream temperature Macroinvertabrates no detection of species tolerant of poor water quality No soil compaction
d r y kpa 200 180 160 140 120 100 80 60 40 Soil Moisture Availability control aspen 2009 control aspen 2010 encroached meadow 2009 encroached meadow 2010 treated aspen 2009 treated aspen 2010 untreated aspen 2009 untreated aspen 2010 w e t 20 0 150 170 190 210 230 250 Julian Day
Herbivory species and intensity 25 20 deer livestock both percent of stands 15 10 5 0 intense moderate light Intensity of browse
Wildlife Types of Fencing Livestock
Seasonal utilization by forage type 80 2006 2007 utilization (%) 60 40 20 0 Early Mid Late Early Mid Late Season aspen herbaceous meadow herbaceous aspen regeneration
Conclusion Lessons learned through monitoring Mechanically removing conifers has been a successful treatment to enhance aspen regeneration Aspen can be treated in riparian areas using responsible logging practices without adverse effects to stream attributes Management opportunities exist as an alternative for fencing in aspen stands with excessive cattle browsing
Shade intolerant Oak Restoration Reproduces vegetative (stump sprouting) and seeding Disturbance dependent
Landscape heterogeneity Structural Diversity: cavities, snags, and dead branches Ecological Importance Provide: acorns and oak mistletoe for a variety of wildlife species (deer, gray squirrels, turkey, and birds)
Treatments Mechanical Thinning Forest structure Oak regeneration Herbaceous and shrub understory Under-burning Herbaceous understory Oak regeneration Shrub cover
Study Area and Design Four treatments no-treatment (7), thin (23), thin and spring burn (3), thin and fall burn (2) Data collected prior to treatment, and 3 and 6 years post treatment Thin and burn treatments have a small sample size Treatments implemented in different years
Results Significant reduction in basal area for all treatments 400 350 300 250 Basal Area Control Thin TSB TFB sq ft/ac 200 150 100 50 0 0 3 6 post-trt year
Oak Response 0.18 Oak Canopy Cover 1 st year post treatment 0.16 0.14 0.12 percent 0.1 0.08 0.06 0.04 0.02 0 Control Thin TSB TFB 6 th year post treatment 45 40 35 Oak Basal Area 0 1 30 3 ft 2 /ac 25 20 6 15 10 5 0 Control Thin TSB TFB Treatment
Results - thin pre-treatment 2004 1 year post treatment 2006 6 years post treatment 2011
Results thin and burn pre treatment 2004 1st year post burn 2009 3 rd year post burn 2011
density (st/ac) density (st/ac) 350 300 250 200 150 100 50 0 350 300 250 200 150 100 50 0 Results Successful black oak regeneration following treatment Basal Sprout Density Control Thin TFB TSB 0 1 2 3 6 Trunk Sprout Density 0 1 2 3 6 treatment year
stems/ac Results Successful black oak regeneration following thinning and fall burn 35 30 25 20 15 10 oak seedlings B con thin tsp tfb 5 0 A 0 3 6 year post treatment
Results - understory Pre-treatment 3 rd year post burn percent percent 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 perennial graminoids 0 3 6 shrub 0 3 6 year post treatment con thin tsp tfb con thin tsp tfb
Conclusion Lessons learned through monitoring Oak vigor and regeneration increased following treatments Cutting black oak trees can stimulate stump sprouting but we do not recommend cutting oak in young stand especially if treatments includes burning Perennial grasses significantly increased in following thinning and burning. Conifer removal using thinning and burning is required to promote, enhance, and sustain the ecological value of these hardwood communities.
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