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 Great Basin Institute - Nevada Conservation Corps - Evaluation Report 2019-2020

Report Completed 12/17/2020

Prepared by

Elizabeth Christiansen, Ph.D.

 

Prepared for

Great Basin Institute

Nevada Conservation Corps

Evaluation Report: UNR: Great Basin Institute
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Great Basin Institute Nevada Conservation Corps Evaluation Report 2019-2020

Introduction

The Great Basin Institute is an interdisciplinary field studies organization that promotes 

environmental research, education, and conservation throughout the West. Founded in 1998 at 

the University of Nevada, GBI advances applied research to support science-based adaptive 

management of public lands. Celebrating its 22nd year of operation, GBI employs over 600 

researchers and field technicians to support conservation initiatives. The Nevada Conservation 

Corps (NCC), a program of GBI, is an environmental service program dedicated to promoting field 

research and direct conservation service. NCC has administered 20 continuous AmeriCorps 

program years. The Corps supports Nevada’s communities and public lands through the 

deployment of forestry teams to mitigate fire threats, reduce the spread of invasive species, and 

restore and re-designate trails. NCC’s trained monitoring and assessment teams capture critical 

data on the condition of forest and rangeland health. 

NCC’s program activities include crew-based services that reduce wildland fire threat through 

fuels reduction and habitat restoration. In addition to such services, Corps members treat and 

abate noxious weeds, as well perform tasks such as post-fire re-seeding and native plant reintroduction. Trail management measures, including the designation and restoration of trail 

routes, also support reduction of fire threat by reducing fuels along trail corridors, maintaining 

fuel breaks, and offering improved access to fire locations. To support agency decision-making, 

NCC’s Assessment, Inventory, and Monitoring teams evaluate and characterize forest and range 

health conditions and provide data to determine restoration efficacy. The primary anticipated 

short-term outcomes targeted by NCC program activities include reducing the risk of catastrophic 

wildfire; increasing accessibility and safe condition of usable recreational trail systems; and 

completing deliverables on datasets and monitoring protocols. 

GBI contracted with the Center for Program Evaluation at the University of Nevada, Reno to 

design and evaluate the NCC program in the 2018-2021 grant cycle. This report describes the 

results of years 1 and 2 (2019 and 2020) of an impact evaluation for GBI’s NCC. The goal of the 

evaluation is to evaluate the impact and efficacy of wildfire fuels reduction on reducing wildfire 

risk for Nevada’s public lands. Silvicultural treatments included second entry of mastication 

and chaining treatment units aimed to create within-stand heterogeneity of various gaps, 

canopy layers, and densities while also reducing fuels through stand level thinning practices 

(Reinhardt et al. 2008; USDA-USDI 2014). Across treatments, large trees were favored for 

retention to promote increases in average stem diameters across all species. Resilience is 

maintained by ensuring a diversity of species, sizes, and age classes that can respond favorably 

to the range of potential disturbances (Stephens et al. 2009; Fule ́ et al. 2012).
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Methods

Research Question. For the impact evaluation, a pre-post quasi-experimental design (QED) study 

was conducted with a matched comparison group to answer the research question: Did Nevada 

Conservation Corps fuels reduction treatments improve fire regime condition class and therefore 

reduce wildfire risk for Nevada’s public lands compared to similar sites where fuels were not 

treated? 

Study Design. A QED was chosen because random selection of treatment sites was not feasible 

since projects and locations are determined by the needs of project partners. The QED will 

compared mean changes in fire regime condition class (FRCC) from pre-treatment to posttreatment for project sites and for untreated comparison sites. A FRCC is a classification of the 

amount of departure from the natural fuels regime (reference Attachment B). The three classes 

are based on low (FRCC 1), moderate (FRCC 2), and high (FRCC 3) departure from the central 

tendency of the natural (historical) regime. Low departure is considered to be within the natural 

(historical) range of variability, while moderate and high departures are outside. A higher FRCC 

indicates greater departure from the natural regime, and higher risk for catastrophic wildfire. 

Sampling methods and sample size. To achieve adequate sample size, staff from CPE utilized 

G*Power3.1 statistical software to conduct a priori power analysis using a two-tailed 

independent sample t-test. A total sample size of 210 (105 treatment sites and 105 comparison 

sites) was determined to be sufficient. The program planned to sample at least 35 treatment and 

35 comparison sites during each collection period. Data were collected at three time points, with 

105 treatment and 105 comparison sites for a total of 210 samples (Table 1). 

Table 1

Number of treatment and comparison sites by sample year

Sample Year Number of Treatment Sites Number of Comparison Sites

2019 35 35

2020_a 35 35

2020_b 35 35

Total 105 105

To establish FRCC for each sample site, GBI characterized the fuel load conditions in treatment 

and comparison sites using the Fuel Load Sample Method, also known as the Brown’s Planar 

Intercept Method (https://www.fs.usda.gov/treesearch/pubs/24059). This method is commonly 

used in forestry to assess fuel load and establish ratings for FRCC and fire risk. The number and 

location of samples per project site was determined by the total acreage of the project site and 

proposed fuels reduction treatments. Comparison sites were selected according to the following 

criteria: slope aspect, plant species, and plant density. In order to collect fuel load data, GPS units 

were used to archive sample site locations, digital cameras were used to photo document each 
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sample site, transect tape was used to establish transect lines, and clinometer were used to 

measure slope. Figures 1 and 2 show the treatment and comparison sites for two 2020 locations. 

Fuel Load Data Analysis. After fuel load data were collected for treatment and comparison sites, 

NCC agency project partners reviewed the fuel load data and photo points to assess and assign 

the FRCC for the sample sites pre- and post-treatment. GBI submitted the FRCC data to CPE for 

analysis. 

Results

An ANCOVA was calculated to determine the effect of the treatment on post-intervention Fire 

Regime Condition Class after controlling for pre-intervention Fire Regime Condition Class. After 

adjustment for pre-treatment Fire Regime Condition Class, there was a statistically significant 

difference in mean post-treatment Fire Regime Condition Class between the treatment and 

comparison sites, F(1, 207) = 83.4, p < .001, partial η2 = .287. Mean post-intervention Fire Regime 

Condition Class was statistically significantly lower in the treatment version versus the 

comparison sites (mean difference of -.386 (95% CI, -.469 to -.302, p< .001) (see also Table 2). 

Figures 1 and 2. 2020 Fuel Load Treatment and Comparison Sample Sites
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Table 2 

Adjusted and Unadjusted Intervention Means and Variability for Post-Intervention Fire 

Regime Condition Class with Pre-Intervention Fire Regime Condition Class as a Covariate

Unadjusted Adjusted

N M SD M SE

Treatment 105 2.10 .31 2.06 .03 

Comparison 105 2.39 .55 2.44 .03 

Note: N = number of participants, M = Mean, SD = Standard Deviation, SE = Standard Error

Conclusion

The results of the quasi-experimental evaluation study demonstrate that the NCC treatment of 

public land was effective in reducing the fire regime condition class (FRCC) of the treated land 

compared to the untreated comparison sites, thereby reducing the risk of catastrophic wildfire. 

The effect size of the treatment intervention as found to be large, with a partial eta squared value 

of .287. This large effect size will permit a smaller number of treatment and comparison site to 

be sampled in future grant cycles and still anticipate significant differences between the 

treatment and comparison sites. The results of the evaluation study provide evidence of the 

success of NCC’s efforts. We can conclude that NCC’s fuel reduction program activities are indeed 

effective methods to achieve the program goals. 

References

Brown JK (1974) Handbook for inventorying downed woody material. USDA Forest Service, 

Intermountain Forest and Range Experiment Station, General Technical Report INT-16. 

(Ogden, UT, USA)

Reinhardt ED, Keane RE, Calkin DE, Cohen JD (2008) Objectives and considerations for wildland 

fuel treatment in forested ecosystems of the interior western United States. Forest 

Ecology and Management 256, 1997–2006. doi:10.1016/J.FORECO.2008.09.016

Stephens SL, Agee JK, Fule ́ PZ, North MP, Romme WH, Swetnam TW, Turner MG (2013) 

Managing forests and fire in changing climates. Science 342, 41–42. 

doi:10.1126/SCIENCE.1240294

Stephens SL, Collins BM, Fettig CJ, Finney MA, Hoffman CM, Knapp EE, North MP, Safford 

H,Wayman RB (2018) Drought, tree mortality, and wildfire in forests adapted to 

frequent fire. Bioscience 8, 77–88. doi:10.1093/BIOSCI/BIX146.