Thomas A. Spies's research while affiliated with Pacific Northwest Research Institute and other places
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Publications (200)
Web Table 1. To Jones et al 2022.
Recent intense fire seasons in Australia, Borneo, South America, Africa, Siberia, and western North America have displaced large numbers of people, burned tens of millions of hectares, and generated societal urgency to address the wildfire problem (Bowman et al. 2020). Nearly all terrestrial ecosystems, however, burn with some degree of regularity,...
Fire has been an important catalyst of change in Pacific Northwest forests throughout the Holocene. The role of fire varied across this biophysically diverse region prior to European colonization, but fire exclusion and logging drastically altered forest conditions during the 19th and 20th centuries. Despite recent increases in area burned and seve...
Understanding ownership effects on large wildfires is a precursor to the development of risk governance strategies that better protect people and property and restore fire-adapted ecosystems. We analyzed wildfire events in the Pacific Northwest from 1984 to 2018 to explore how area burned responded to ownership, asking whether particular ownerships...
After a century of intensive logging, federal forest management policies were developed in the 1990s to protect remaining large trees and old forests in the western US. Today, due to rapidly changing ecological conditions, new threats and uncertainties, and scientific advancements, some policy provisions are being re‐evaluated in interior Oregon an...
The Northwest Forest Plan (NWFP) has guided the management of 17 federal forests in the US Pacific Northwest for the past 25 years. The existing management plans for these national forests – which were amended by the NWFP – are now being evaluated for revision under the US Forest Service's 2012 planning rule. To help inform federal land managers, w...
The US Endangered Species Act has enabled species conservation but has differentially impacted fire management and rare bird conservation in the southern and western US. In the South, prescribed fire and restoration‐based forest thinning are commonly used to conserve the endangered red‐cockaded woodpecker (Picoides borealis; RCW), whereas in the We...
Before the advent of intensive forest management and fire suppression, western North American forests exhibited a naturally occurring resistance and resilience to wildfires and other disturbances. Resilience, which encompasses resistance, reflects the amount of disruption an ecosystem can withstand before its structure or organization qualitatively...
Scientific knowledge and tools have central roles in contemporary federal forest programs that promote restoration in large landscapes and across ownerships. Although we know much about the role of science in decisionmaking and ways that science can be better linked to practice, we know less about manager perspectives about science and science tool...
The Northwest Forest Plan (NWFP) initiated one of the most sweeping changes to forest management in the world, affecting 10 million hectares of federal land. The NWFP is a science-based plan incorporating monitoring and adaptive management and provides a unique opportunity to evaluate the influence of policy. We used >25 years of region-wide bird s...
A century of fire suppression across the Western US has led to more crowded forests and increased competition for resources. Studies of forest thinning or stand conditions after mortality events have provided indirect evidence for how competition can promote drought stress and predispose forests to severe fire and/or bark beetle outbreaks. Here we...
We developed and applied a wildfire simulation package in the Envision agent-based landscape modelling system. The wildfire package combines statistical modelling of fire occurrence with a high-resolution, mechanistic wildfire spread model that can capture fine scale effects of fire feedbacks and fuel management, and replicate restoration strategie...
Context
In the interior Northwest, debate over restoring mixed-conifer forests after a century of fire exclusion is hampered by poor understanding of the pattern and causes of spatial variation in historical fire regimes.
Objectives
To identify the roles of topography, landscape structure, and forest type in driving spatial variation in historical...
The fundamental assumption of the NWFP was that the breadth of the biological and socioeconomic strategies would achieve its biodiversity conservation and socioeconomic goals, and that those goals were also compatible with each other. Scientists and managers now have the perspective afforded by 23 years of research, monitoring, and field experience...
The 1994 Northwest Forest Plan (NWFP) was developed to resolve debates over old-growth forests, endangered species, and timber production on federal forests in the range of the northern spotted owl. This three-volume science synthesis, which consists of 12 chapters that address various ecological and social concerns, is intended to inform forest pl...
Expanding the footprint of natural fire has been proposed as one potential solution to increase the pace of forest restoration programs in fire-adapted landscapes of the western USA. However, studies that examine the long-term socio-ecological trade-offs of expanding natural fire to reduce wildfire risk and create fire resilient landscapes are lack...
This is the executive summary of a three-volume science synthesis that addresses various ecological and social concerns regarding management of federal forests encompassed by the Northwest Forest Plan (NWFP). Land managers with the U.S. Forest Service provided questions that helped guide preparation of the synthesis. It builds on the 10-, 15-, and...
This is the executive summary of a three-volume science synthesis that addresses various ecological and social concerns regarding management of federal forests encompassed by the Northwest Forest Plan (NWFP). Land managers with the U.S. Forest Service provided questions that helped guide preparation of the synthesis. It builds on the 10-, 15-, and...
Wildland fire suppression practices in the western United States are being widely scrutinized by policymakers and scientists as costs escalate and large fires increasingly affect social and ecological values. One potential solution is to change current fire suppression tactics to intentionally increase the area burned under conditions when risks ar...
Wildfires pose a unique challenge to conservation in fire-prone regions, yet few studies quantify the cumulative effects of wildfires on forest dynamics (i.e. changes in structural conditions) across landscape and regional scales. We assessed the contribution of wildfire to forest dynamics in the eastern Cascade Mountains, USA from 1985 to 2010 usi...
Coupled human and natural systems (CHANS) research highlights reciprocal interactions (or feedbacks) between biophysical and socioeconomic variables to explain system dynamics and resilience. Empirical models often are used to test hypotheses and apply theory that represent human behavior. Parameterizing reciprocal interactions presents two challen...
While advances in remote sensing have made stand, landscape, and regional assessments of the direct impacts of disturbance on forests quite common, the edge influence of timber harvesting on the structure of neighboring unharvested forests has not been examined extensively. In this study, we examine the impact of historical timber harvests on basal...
Scientists are increasingly called upon to integrate across ecological and social disciplines to tackle complex coupled human and natural system (CHANS) problems. Integration of these disciplines is challenging and many scientists do not have experience with large integrated research projects. However, much can be learned about the complicated proc...
This study investigates how federal, state, and private corporate forest owners in a fire-prone landscape of southcentral Oregon manage their forests to reduce wildfire hazard and loss to high-severity wildfire. We evaluate the implications of our findings for concepts of social-ecological resilience. Using interview data, we found a high degree of...
Fire is an important disturbance in many forest landscapes, but there is heightened concern regarding recent wildfire activity in western North America. Several regional-scale studies focus on high-severity fire, but a comprehensive examination at all levels of burn severity (i.e., low, moderate, and high) is needed to inform our understanding of t...
Fire-prone landscapes present many challenges for both managers and policy makers in developing adaptive behaviors and institutions. We used a coupled human and natural systems framework and an agent-based landscape model to examine how alternative management scenarios affect fire and ecosystem services metrics in a fire-prone multiownership landsc...
We use the simulation model Envision to analyze long-term wildfire dynamics and the effects of different fuel management scenarios in central Oregon, USA. We simulated a 50-year future where fuel management activities were increased by doubling and tripling the current area treated while retaining existing treatment strategies in terms of spatial d...
The moist coniferous forests of the Pacific Northwest are notable for the dominance of long-lived evergreen conifers, productivity, and the massiveness of the older forests (Franklin and Dyrness 1988; Franklin and Halpern 2000) (plate 2A). The environment of this region is extremely favorable to forest growth, with its moderate temperatures, high p...
Our understanding of what constitutes the freshwater ecosystems, watersheds, and landscapes in moist coniferous forests is continually evolving. To date, much of the aquatic-system focus has been on relatively small spatial scales, such as stream habitat units and reaches (chap. 14). However, a variety of entities, including interested publics, int...
Timber harvest can adversely affect forest biota. Recent research and application suggest that retention of mature forest elements (‘retention forestry’), including unharvested patches (or ‘aggregates’) within larger harvested units, can benefit biodiversity compared to clearcutting. However, it is unclear whether these benefits can be generalized...
Tree mortality is an important demographic process and primary driver of forest dynamics, yet there are relatively few plot-based studies that explicitly quantify mortality and compare the relative contribution of endogenous and exogenous disturbances at regional scales. We used repeated observations on 289,390 trees in 3673 1 ha plots on U.S. Fore...
Wildfire risk in temperate forests has become a nearly intractable problem that can be characterized as a socioecological "pathology": that is, a set of complex and problematic interactions among social and ecological systems across multiple spatial and temporal scales. Assessments of wildfire risk could benefit from recognizing and accounting for...
Forest carbon (C) density varies tremendously across space due to the inherent heterogeneity of forest ecosystems. Variation of forest C density is especially pronounced in mountainous terrain, where environmental gradients are compressed and vary at multiple spatial scales. Additionally, the influence of environmental gradients may vary with fores...
Forest policymakers and managers have long sought ways to evaluate the capability of forest landscapes to jointly produce timber, habitat, and other ecosystem services in response to forest management. Currently, carbon is of particular interest as policies for increasing carbon storage on federal lands are being proposed. However, a challenge in j...
Forests play a critical role sequestering atmospheric carbon dioxide, partially offsetting greenhouse gas emissions and thereby mitigating climate change. Forest management, natural disturbances and the fate of carbon in wood products strongly influence carbon sequestration and emissions in the forest sector. Government policies, carbon offset and...
Increasingly, objectives for forests with moderate- or mixed-severity fire regimes are to restore successionally diverse landscapes that are resistant and resilient to current and future stressors. Maintaining native species and characteristic processes requires this successional diversity, but methods to achieve it are poorly explained in the lite...
Disasters result from hazards affecting vulnerable people. Most disasters research by anthropologists focuses on vulnerability; this article focuses on natural hazards. We use the case of wildfire mitigation on United States Forest Service lands in the northwestern United States to examine social, political, and economic variables at multiple scale...
Despite its importance to biodiversity and ecosystem function, patterns and drivers of regional scale variation in forest structure and development are poorly understood. We characterize structural variation, create a hierarchical classification of forest structure, and develop an empirically based framework for conceptualizing structural developme...
The provisioning of ecosystem services to society is increasingly under pressure from global change. Changing disturbance regimes are of particular concern in this context due to their high potential impact on ecosystem structure, function and composition. Resilience-based stewardship is advocated to address these changes in ecosystem management, b...
In recent decades, much work has been invested to describe forest allocations with high societal values. Yet, few comparative analyses have been conducted on their importance and differences across the regions of the globe. This paper introduces a conceptual framework to characterize forest priority areas defined as areas with identified higher imp...
Twentieth-century land management has altered the structure and composition of mixed-conifer forests and decreased their resilience to fire, drought, and insects in many parts of the Interior West. These forests occur across a wide range of environmental settings and historical disturbance regimes, so their response to land management is likely to...
Fire-prone landscapes are not well studied as coupled human and natural systems (CHANS) and present many challenges for understanding and promoting adaptive behaviors and institutions. Here, we explore how heterogeneity, feedbacks, and external drivers in this type of natural hazard system can lead to complexity and can limit the development of mor...
Background/Question/Methods
Thornton T. Munger, the first Pacific Northwest Research Station Director for the Forest Service, established the first long-term forest research plots in the Pacific Northwest USA in 1910 to better understand growth and timber yield of Douglas-fir (Pseudotsuga menziesii) trees. The location of these plots would eventu...
Background/Question/Methods
Tree mortality is a primary driver of structure and function in forested ecosystems worldwide. It has recently emerged as a major focus of ecological research following the occurrence of large scale “die-off” events associated with increased occurrence of wildfire and drought related epidemics of disease and pathogens....
Early-seral ecosystems make important contributions to regional biodiversity by supporting high abundance and diversity of many plant and animal species that are otherwise rare or absent from closed-canopy forests. Therefore, the period of post-fire tree establishment is a key stage in forest stand and ecosystem development that can be viewed in th...
Disturbances are key drivers of forest ecosystem dynamics, and forests are well adapted to their natural disturbance regimes. However, as a result of climate change, disturbance frequency is expected to increase in the future in many regions. It is not yet clear how such changes might affect forest ecosystems, and which mechanisms contribute to (cu...
Land managers in the Pacific Northwest have reported a need for updated scientific
information on the ecology and management of mixed-conifer forests east of the
Cascade Range in Oregon and Washington. Of particular concern are the moist
mixed-conifer forests, which have become drought-stressed and vulnerable to
high-severity fire after decades of...
Most silvicultural methods have been developed with the principal aim of ensuring adequate regeneration of commercial tree species after harvesting. Much less effort has been directed towards developing methods that benefit the re-establishment of all forest biodiversity. The concept of ‘forest influence’ relates the probability of species re-estab...
Forests dominated by Douglas-fir and western hemlock in the Pacific Northwest of the United States have strongly influenced concepts and policy concerning old-growth forest conservation. Despite the attention to their old-growth characteristics, a tendency remains to view their disturbance ecology in relatively simple terms, emphasizing infrequent,...
We examine challenges and opportunities involved in applying ecosystem services to public land management with an emphasis on national forests in the United States. We review historical forest management paradigms and related economic approaches, outline a conceptual framework defining the informational needs of forest managers, and consider the fe...
National Forests in the dry forest provinces on the east-side of the Oregon and Washington Cascades have been managed under the guidelines of local Forest Plans and the Northwest Forest Plan (NWFP), both of which specify large areas of late-successional reserves (LSRs). In contrast, the recently-released USDI Fish and Wildlife Service Revised Recov...
Wildfire links social and ecological systems in dry-forest landscapes of the United States. The management of these landscapes, however, is bifurcated by two institutional cultures that have different sets of beliefs about wildfire, motivations for managing wildfire risk, and approaches to administering policy. Fire protection, preparedness, and re...
Tree invasions have been documented throughout Northern Hemisphere high elevation meadows, as well as globally in many grass and forb-dominated ecosystems. Tree invasions are often associated with large-scale changes in climate or disturbance regimes, but are fundamentally driven by regeneration processes influenced by interactions between climatic...
Canopy gaps created by tree mortality can affect the speed and trajectory of vegetation growth, species’ population dynamics, and spatial heterogeneity in mature forests. Most studies focus on plant development within gaps, yet gaps also affect the mortality and growth of surrounding trees, which influence shading and root encroachment into gaps an...
Background/Question/Methods
Old-growth mixed-conifer forests (OMCF) are found in the transition between dry ponderosa pine, Pinus ponderosa, woodlands and moist grand fir, Abies grandis, forest types. A combination of steep ecological gradients and a mixed-severity fire regime historically created a mosaic of structurally and compositionally dive...
Background/Question/Methods
Long-term research can play a critical role in addressing “Grand Challenges” in environmental stewardship. In this presentation we examine efforts at five Long-Term Ecological Research (LTER) studies across the US to inform policy, management and conservation decisions related to forests at local, regional, and nationa...
Background/Question/Methods The U.S. approach to dealing with wildfire is typically to fragment the fire-prone landscape (FPL) into a “wildland-urban interface (WUI)” under the influence of local fire management agencies and a fire-prone wildland under the influence of land managers. These two fire worlds are often seen as socially, economically an...
Background/Question/Methods
There is increasing evidence that tree mortality rates in old-growth forests have increased in the western United States since the 1970’s. Some of the highest rates have been documented in the Pacific Northwest, but there is little understanding of how mortality rates vary along major environmental and climatic gradien...
Forest ecosystems are the most important terrestrial carbon (C) storage globally, and presently mitigate anthropogenic climate change by acting as a large and persistent sink for atmospheric CO2. Yet, forest C density varies greatly in space, both globally and at stand and landscape levels. Understanding the multi-scale drivers of this variation is...
Wildfires remain a major threat to Northern Spotted Owl habitat in Cen-tral Oregon, and there is an urgent need for tools to support the development of effective conservation planning strategies. We describe the managed forest ecosystem in Central Oregon as a coupled human and natural system and apply the agent-based modelling framework ENVISION fo...
Long-term research should play a crucial role in addressing grand challenges in environmental stewardship. We examine the efforts of five Long Term Ecological Research Network sites to enhance policy, management, and conservation decisions for forest ecosystems. In these case studies, we explore the approaches used to inform policy on atmospheric d...
Forest ecosystem dynamics emerges from nonlinear interactions between adaptive biotic agents (i.e., individual trees) and their relationship with a spatially and temporally heterogeneous abiotic environment. Understanding and predicting the dynamics resulting from these complex interactions is crucial for the sustainable stewardship of ecosystems,...
