Richy J. Harrod

The national Fire and Fire Surrogate study: effects of fuel reduction methods on forest vegetation structure and fuels

Changes in vegetation and fuels were evaluated from measurements taken before and after fuel reduction treatments (prescribed fire, mechanical treatments, and the combination of the two) at 12 Fire and Fire Surrogate (FFS) sites located in forests with a surface fire regime across the conterminous United States. To test the relative effectiveness of fuel reduction treatments and their effect on ecological parameters we used an information-theoretic approach on a suite of 12 variables representing the overstory (basal area and live tree, sapling, and snag density), the understory (seedling density, shrub cover, and native and alien herbaceous species richness), and the most relevant fuel parameters for wildfire damage (height to live crown, total fuel bed mass, forest floor mass, and woody fuel mass). In the short term (one year after treatment), mechanical treatments were more effective at reducing overstory tree density and basal area and at increasing quadratic mean tree diameter. Prescribed fire treatments were more effective at creating snags, killing seedlings, elevating height to live crown, and reducing surface woody fuels. Overall, the response to fuel reduction treatments of the ecological variables presented in this paper was generally maximized by the combined mechanical plus burning treatment. If the management goal is to quickly produce stands with fewer and larger diameter trees, less surface fuel mass, and greater herbaceous species richness, the combined treatment gave the most desirable results. However, because mechanical plus burning treatments also favored alien species invasion at some sites, monitoring and control need to be part of the prescription when using this treatment.

Impacts of erosion control treatments on native vegetation recovery after severe wildfire in the Eastern Cascades, USA

Slope stabilisation treatments like mulching and seeding are used to increase soil cover and reduce runoff and erosion following severe wildfires, but may also retard native vegetation recovery. We evaluated the effects of seeding and fertilisation on the cover and richness of native and exotic plants and on individual plant species following the 2004 Pot Peak wildfire in Washington State, USA. We applied four seeding and three fertilisation treatments to experimental plots at eight burned sites in spring 2005 and surveyed vegetation during the first two growing seasons after fire. Seeding significantly reduced native non-seeded species richness and cover by the second year. Fertilisation increased native plant cover in both years, but did not affect plant species richness. Seeding and fertilisation significantly increased exotic cover, especially when applied in combination. However, exotic cover and richness were low and treatment effects were greatest in the first year. Seeding suppressed several native plant species, especially disturbance-adapted forbs. Fertilisation, in contrast, favoured several native understorey plant species but reduced tree regeneration. Seeding, even with native species, appears to interfere with the natural recovery of native vegetation whereas fertilisation increases total plant cover, primarily by facilitating native vegetation recovery.

Adaptations to climate change: Colville and Okanogan-Wenatchee National Forests

Gaines, William L.; Peterson, David W.; Thomas, Cameron A.; Harrod, Richy J. 2012. Adaptations to climate change: Colville and OkanoganWenatchee National Forests. Gen. Tech. Rep. PNW-GTR-862. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 34 p. Forest managers are seeking practical guidance on how to adapt their current practices and, if necessary, their management goals, in response to climate change. Science-management collaboration was initiated on national forests in eastern Washington where resource managers showed a keen interest in science-based options for adapting to climate change at a 2-day workshop. Scientists and managers reviewed current climate change science and identified resources vulnerable to expected climate change. Vulnerabilities related to vegetation and habitat management included potential reductions in forest biodiversity and low forest resilience to changing disturbance regimes. The vulnerabilities related to aquatic and infrastructure resources included changing water quality and quantity, the risk to roads and other facilities from changes to hydrologic regimes, and the potential loss of at-risk aquatic species and habitats. Managers then worked in facilitated groups to identify adaptations that could be implemented through management and planning to reduce the vulnerability of key resources to climate change. The identified adaptations were grouped under two major headings: Increasing Ecological Resiliency to Climate Change, and Increasing Social and Economic Resiliency to Climate Change. The information generated from the science-management collaborative represents an initial and important step in identifying and prioritizing tangible steps to address climate change in forest management. Next would be the development of detailed implementation strategies that address the identified management adaptations.

Landscape Evaluation and Restoration Planning

Contemporary land managers are beginning to understand that landscapes of the early 20th century exhibited complex patterns of compositional and structural conditions at several different scales, and that there was interplay between patterns and processes within and across scales. Further, they understand that restoring integrity of these conditions has broad implications for the future sustainability of native species, ecosystem services, and ecological processes. Many too are hungry for methods to restore more natural landscape patterns of habitats and more naturally functioning disturbance regimes; all in the context of a warming climate. Attention is turning to evaluating whole landscapes at local and regional scales, deciphering their changes and trajectories, and formulating scale-appropriate landscape prescriptions that will methodically restore ecological functionality and improve landscape resilience. Here, we review published landscape evaluation and planning applications designed in EMDS. We show the utility of EMDS for designing transparent local landscape evaluations, and we reveal approaches that have been used thus far. We begin by briefly reviewing six projects from a global sample, and then review in greater depth four projects we have developed with our collaborators. We discuss the goals and design of each project, its methods and utilities, what worked well, what could be improved and related research opportunities. It is our hope that this review will provide helpful insights into how spatial decision support technologies may be used to evaluate and plan for local and perhaps larger-scale landscape restoration projects.

Flatland in flames: a two-dimensional crown fire propagation model

The canopy bulk density metric is used to describe the fuel available for combustion in crown fire models. We propose modifying the Van Wagner crown fire propagation model, used to estimate the critical rate of spread necessary to sustain active crown fire, to use foliar biomass per square metre instead of canopy bulk density as the fuel input. We tested the efficacy of our proposed model by comparing predictions of crown fire propagation with Van Wagner’s original data. Our proposed model correctly predicted each instance of crown fire presented in the seminal study. We then tested the proposed model for statistical equivalence to the original Van Wagner model using two contemporary techniques to parameterize canopy bulk density. We found the proposed and original models to be statistically equivalent when canopy bulk density was parameterized using the method incorporated in the Fire and Fuels Extension to the Forest Vegetation Simulator (difference < 0.5 km h–1, α = 0.05, n = 2626), but not when parameterized using the method of Cruz and others. Use of foliar biomass per unit area in the proposed model makes for more accurate and easily obtained fuel estimates without sacrificing the utility of the Van Wagner model.