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Current and recent research projects

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Dissertations and theses completed through the lab


CURRENT AND RECENT RESEARCH PROJECTS

Spruce Beetle and Wildfire Interactions under Varying Climate in the Colorado Rockies.  Sponsor: National Science Foundation, Geography and Spatial Science Program. 2013-2016.


This research will examine relationships between outbreaks of spruce bark beetles and wildfire activity in coniferous forests of the Rocky Mountains.  Coincident with warmer temperatures, since the early 1990s synchronous outbreaks of native bark beetles have been occurring throughout coniferous forests of western North America, from Alaska to the U.S. Southwest.  Extensive tree mortality caused by bark beetle outbreaks is triggering major changes in forest landscapes and their associated ecosystem services. This research will address the following questions about interactions between wildfire and spruce beetle outbreaks under varying climate and their consequences for ecosystem services. 1) How does climatic variation affect the initiation and spread of spruce beetle outbreaks across complex landscapes?  2) How does prior disturbance by windstorm, logging, and fire affect the subsequent occurrence and severity of spruce beetle outbreak? 3) In the context of a recently warmed climate, how do spruce beetle outbreaks affect forest structure and composition? 4) How do spruce beetle outbreaks affect fuels and potential wildfire activity under varying climatic conditions?  5) How will climate change and the climate-sensitive disturbances of wildfire and spruce beetle activity affect future ecosystem services in the subalpine zone of the southern Rocky Mountains under varying scenarios of adaptive forest management?  The first four questions will be addressed by empirical research including extensive tree-ring reconstructions of past disturbances, re-measurement of permanent forest plots, field measurements of effects of spruce beetle outbreaks on fuels, fire behavior modeling, and spatiotemporal analyses of the spread of recent spruce beetle outbreaks. The fifth question will be examined through simulation modeling of future forest conditions and their consequences for key selected ecosystem services – biodiversity, wildlife habitat, and resilience to environmental change.
The intellectual merit of this project lies in its contribution to understanding fire-beetle interactions under varying climate conditions and their consequences for ecosystem services.  The project’s broader impacts are centered on its objectives to address societal needs for information about climate impacts on bark beetle outbreaks, feedbacks to and from wildfire and other disturbances, and sustaining ecosystem services. The project will provide current science information in support of forest management and decision making needs through evaluation of different adaptive management strategies to maintain biodiversity, wildlife habitat, and ecosystem resilience in the face of climate change. The project will develop pre-collegiate and collegiate-level curriculum material on wildfire and bark beetle interactions in cooperation with Colorado and Clark Universities’ public outreach programs.  It will create field and laboratory educational and training experiences for graduate and undergraduate students as well as an early career postdoctoral researcher.  To further enhance public education on fire-beetle topics, the project will produce a documentary video as well as a website of Frequently Asked Questions about bark beetles and wildfire in the face of climate change.

WildFIRE PIRE: Feedbacks and Consequences of Altered Fire Regimes in the Face of Climate and Land-Use Change in Tasmania, New Zealand, and the Western U.S.
Sponsor: National Science Foundation, Office of International Science and Engineering. 2010-2015

Fire is an important natural disturbance in temperate forested ecosystems and serves as a critical but poorly understood link between climate change and biosphere response. In recent decades, extreme drought, land-cover alteration, and non-native plant invasions in temperate regions around the world have altered natural fire regimes at an alarming rate, and in the process, threatened native biodiversity and human well-being. Understanding the causes and consequences of altered fire regimes and the feedbacks to land cover, disturbance regimes, carbon cycling, and climate change is a complex and critically important objective of the global climate change research community.  Identifying the climate and human-related drivers of disturbance-regime change is one of the most challenging issues facing natural resource management.  NSF’s  Partnership in International Research and Education (PIRE) is supporting this integrated research, education and outreach project developed collaboratively by Montana State University, University of Idaho, University of Colorado, the USDA Fire Lab, and several partner institutions in Australia and New Zealand.  We are utilizing the similarities and contrasts in fire, climate, and land-use interactions in three fire-prone settings as a platform for integrated fire-science research and education: Tasmania, New Zealand, and the western U.S.  The project brings together a diverse team of researchers and educators and employs state-of-the-art field, laboratory, and modeling tools to advance our understanding of regional and hemispheric fire-climate linkages and land-use feedbacks.

The multi-faceted and multi-scalar approach of this investigation will (1) enable integrated approaches in basic and applied fire science, including comparisons of historical data in fire regime assessments and use of modern approaches to reconstruct past fire activity; (2) expand the matrix of natural experiments offered by individual regions; and (3) provide much-needed information in support of ecosystem science and management in all regions. The research contributes to initiatives that seek to characterize the consequences of climate change and variability and land-cover conversion through (1) an examination of key biospheric variables, (2) the use of paleo- and modern environmental data to link responses among sites, regions, and hemispheres; and (3) an analysis of the feedbacks between fire regimes, land-cover, humans, and climate change.

Wildfire Regime Shifts in Southern South America from Tree-ring Reconstructed Fire History Networks: Climatic Controls, Land Use, and Ecological Feedbacks.
Sponsor: National Science Foundation, Geography and Spatial Science Program. 2010-2013.

In many parts of the world, extreme wildfire events and increases in area burned since the early 1980s have been attributed to a combination of global warming and land-use trends.  Some land-use practices may convert fire-resistant forests to more fire-prone vegetation types, thus creating positive feedbacks towards more fires, more CO2 release, and enhanced warming.  Numerous studies in the Northern Hemisphere have linked variability in wildfire activity to both 20th century warming and teleconnections with El Niño-Southern Oscillation (ENSO) in the tropical Pacific and high-latitude climate modes such as the Arctic Oscillation.  In the Southern Hemisphere the leading extratropical mode of atmospheric variability is the Southern Annular Mode (SAM; also known as the Antarctic Oscillation) consisting of a redistribution of atmospheric mass between middle and high latitudes.  Recent changes in the magnitude of the SAM are associated with a strengthening of the westerlies, variations in mid-latitude storm tracks, and warmer-drier conditions in Patagonia. The post-1950 positive trend in SAM is interpreted as a signature of anthropogenic forcing by increased greenhouse gases and/or reduced stratospheric ozone.  We are using tree rings to reconstruct fire history in southern Patagonia over the past 400 years in order to relate variability in fire history to year-to-year variability as well as decadal scale variability of ENSO and SAM. This study also examines how forest burning followed by livestock impacts is converting fire-resistant tall southern beech forests to more flammable open woodlands and grass-shrublands, thus creating a feedback further enhancing fire potential.  We are determining the vegetation and land-use conditions that favor shifts in vegetation types from fire-resistant forests to fire-prone shrublands by mapping pre-burn vegetation from satellite imagery and historical air photos and then field sampling the current vegetation and land-use practices at sites burned in the latter part of the 20th century.

Understanding the site-specific potential for shifts from fire-resistant forests to fire-prone shrublands is essential for mitigating and adapting land-use practices to climate-induced changes in wildfire activity.  Under recent climate trends, weather extremes (including fire-promoting droughts) are increasing in magnitude and frequency, and can have far-reaching implications for ecosystems as well as CO2 emissions to the atmosphere.  The long-term (multi-century) fire records that this study is producing are necessary to understand how these recent trends in fire activity depart from the historical range of variability, and how variability in wildfire activity relates to climate variation as well as land-use trends. 

Wildfire and Mountain Pine Beetle Outbreaks in Subalpine Forests: Cross-Scale Interactions Under Varying Climate.
Sponsor: National Science Foundation, Ecological Studies Program. 2008-2011

Large outbreaks of native bark beetles (Dendroctonus spp.) are occurring throughout coniferous forests of western North America, from western Alaska to the U.S. Southwest and are believed to be related to climatic warming. In Colorado more than 270,000 ha of lodgeple pine forests have recently been infested by mountain pine beetle (D. ponderosae) which has led to widespread public concern about increased fire hazard following beetle kill.

This research addresses four key questions about interactions of wildfire, MPB outbreaks and climate and their potential cross-scale feedbacks in subalpine forests in northern Colorado. 1) How does climatic variation at seasonal, annual, and multi-decadal time scales affect the initiation and spread of MPB outbreaks across complex landscapes? 2) How does the landscape heterogeneity created by prior disturbance by fire affect the risk and/or spread of subsequent disturbance by MPB outbreak across complex landscapes? 3) How does the landscape heterogeneity created by prior disturbance by MPB affect the fuel hazard and risk of wildfire across complex landscapes? 4) How do context-specific contingencies between climate and the landscape template affect the initiation and spread of wildfire and MPB outbreaks across complex landscapes?

Climatic drivers of forest dynamics.
Sponsor: U.S. Geological Survey. 2007-08

Under this project we are re-measuring permanent forest plots installed in the early 1980s in the subalpine zone of the Colorado Front Range to study the effects of climatic variation on the demography of the tree populations. The focus of the research is on the role of drought and warming in the mortality of conifer populations. The 25-year record of tree mortality from the permanent plots is being supplemented by tree-ring dating of tree mortality patterns over a time span of more than a century.

This work is in support of USGS-Biological Resources Discipline’s Western Mountain Initiative (WMI) global change research project.

Fire Risk and Ecological Integrity in the Wildland Urban Interface of the Colorado Front Range.
Sponsor: National Science Foundation, Ecological Studies Program. 2006-2009.

In the western U.S. resource managers are increasingly concerned with the objectives of restoring ecosystems to their pre-settlement conditions while also mitigating the risks of fires to property and resource values. The dual management goals of ecological restoration and fire risk mitigation are not always compatible, especially where natural fire regimes consisted of large, severe fires. This research explores the relationship between forest management, land use change, fire risk and ecological integrity in the wildland-urban interface (WUI) spanning four counties of the Colorado Front Range. This research will develop spatially explicit baseline studies that evaluate how fire exclusion and land use patterns have affected wildfire behavior and the spatial extent of fire risk to people and property across the WUI landscape. Building upon these baseline assessments, the study will consider which spatial combination of land use and forest management scenarios would significantly reduce fire risk while also protecting ecological integrity across a heterogeneous wildland-urban interface. This work integrates natural and human dimensions of resilience and landscape change in the WUI of the Colorado Front Range.

Scientific and communication products will be generated through this project, which will have application to societal questions of how resilient human and natural communities can be sustained in a fire-prone, ever-expanding WUI. These include significant baseline studies of (1) historical fire regimes and forest stand structures across the Colorado Front Range WUI, (2) historical exurban development patterns and effects on the degree and distribution of wildfire risk across the WUI, (3) analysis of departure from historical ecological conditions and an improved wildfire risk map, and (4) spatially explicit evaluation of key fire mitigation and forest restoration options.

This project is integrated with Tania Schoennagel’s David H. Smith Conservation Fellowship on “Fire risk and forest restoration in the wildland urban interface of the Colorado Front Range.”

Climatic variation and disturbance interactions in subalpine Rocky Mountain forests.
Sponsor: National Science Foundation, Ecological Studies Program. 2003-2006.

Much is known in a general sense about how weather conditions at time scales of days to months, affect the potential for fire occurrence and the population dynamics of disturbance-causing insects. However, research is needed on how climatic influences on disturbances vary in relation to broad environmental gradients (i.e. elevation, topography and regional climate) and with the temporal scale of the climatic variation. Although climate may interact with environmental gradients in influencing the spatial and temporal configuration of disturbance events, disturbance interactions (e.g. the influence of a severe insect outbreak on subsequent fire occurrence or vice versa) also act as a source of the spatial heterogeneity in vegetation attributes that influence disturbance processes and subsequent landscape patterns. Disturbance legacies may alter stand susceptibility to climatically sensitive disturbances such as fire and insect outbreaks through the alteration of stand structures (tree ages and sizes) and species composition.

In this context, this project addresses the following three key research questions in southern Rocky Mountain forest ecosystems:
1) What are the climatic conditions, including temporal scale of variability, that are conducive to fire and lethal insect outbreaks across topographic and broad climatic gradients? How are these climatic conditions related to broad-scale drivers of climatic variation such as the El Niño-Southern Oscillation, the Pacific Decadal Oscillation and the Atlantic Multi-decadal Oscillation?
2) How does topographic variability, through its influence on the nature and rate of forest recovery following previous fire and insect outbreaks, affect future susceptibility to disturbance?
3) How do legacies of stand structure resulting from major preceding disturbance by fire and insect outbreaks affect the subsequent frequency, spread, and/or severity of disturbances?

We are examining disturbance processes and forest stand attributes across a range of spatial scales from the regional- to the stand-scale. At the broader regional scale we identify general constraints, primarily regional climatic variation and secondarily broad differences in topography, on the disturbance processes observed at the landscape scale. At the landscape scale we observe where and why disturbances interact in the context of variation in topography, stand structures, and composition (i.e. cover type). Analyses of intra-stand and tree-level variations should reveal evidence of mechanisms that may explain the observed disturbance interactions at the landscape scale, if in fact, mechanisms operating at this scale are causative.

This project is integrated with Tania Schoennagel’s NSF postdoc fellowship on modeling climatic influences on disturbance and forest dynamics in the subalpine zone of the southern Rockies. This involves the use of empirical relationships derived from the research described above to construct climatically driven, probabilistic models of fire spread to compare the potential responses of fire regimes and successional patterns within the subalpine zones of different regions to plausible climate change scenarios. The objective of this research is to utilize fire history maps to tease apart the relative influence of regional vs. local heterogeneity on climatically sensitive fire disturbances, and to consider what effects these altered fire regimes may have on age class and species distributions across heterogeneous landscapes.

Forest decline in Chilean temperate rainforests: a multiscale approach.
Sponsor: National Geographic Society. 2006-2007.

This study is examining fire and regeneration patterns in the long-lived conifer Pilgerodendron uviferum in temperate rainforests of southern South America. The project is examining historical fire patterns in relation to climatic variation and human activities as well as spatial variation in fire occurrence in relation to vegetation type and abiotic environmental factors. One of the goals is to assess the role of fire in the historical dynamics of these forests and to address the question of why post-fire regeneration of this species is sometimes inadequate. Methodologically, the work is based age-structure sampling of post-fire stands, tree-ring dating of fires, and remote sensing documentation of the recent fire record. GIS methods are used to relate fire occurrence to biotic and abiotic variables and create spatially-explicit models of habitat susceptibility to fire and prediction of post-fire regeneration success.

Many of the Pilgerodendron forests affected by fire are in National Parks, and presently park managers lack information on the historic fire regimes and post-fire regeneration in these forests. We expect our findings, including the GIS-layers created in this project, to inform management decisions and policy discussions. This is a one-year seed project integrated with Andres Holz’s NSF Dissertation Award that will allow us to write a larger proposal to support multi-year work of a broader scope on the role of fire in the Patagonian rainforest district of southern Chile mainly at latitudes 43 to 48 degrees S.

Effects of blowdown, beetle outbreak, and fire history on the behavior and effects of the 2002 fires in western Colorado.
Sponsor: The Inter-Agency Joint Fire Science Program. 2003-2006.

Research is needed on the relationships between pre-fire forest conditions and the behavior and effects of the 2002 fires in Colorado. We have high-quality and unique pre-fire data on the extent and severity of fires, blowdown, and spruce beetle outbreak in areas of Routt and White River National Forests that were affected by the 2002 fires. The objectives of this research are to analyze and describe the influences of the pre-fire disturbance history, stand structures, and landscape patterns on the extent and severity of the 2002 fires and ensuing forest recovery in subalpine forests of western Colorado.

Regional and landscape analysis of our existing data and recent Forest Service spatial data sets of the 2002 fires are being conducted in a Geographic Information System (GIS). The focus of this analysis is on the spatial interactions between pre-2002 disturbance events (fire, blowdown, and beetle outbreak) and the spread and severity of the 2002 fires. In the field, finer scale (intra-stand) analysis are being conducted on disturbance interactions and post-fire recovery (i.e. tree regeneration), and permanent plots have been installed to study post-fire patterns of vegetation recovery.

Assessment of current conditions and long-term trends in Colorado’s aspen forests.
Sponsor: U.S.D.A. Forest Service. 2003-2005.

This assessment will provide managers, law-makers, and the public with an initial assessment on (i) where in the State aspen is declining and where it is thriving, and (ii) the specific environmental conditions associated with aspen decline, e.g., the role of local climate, soils, topography, browsing pressure, fire history, logging history, and other factors.

The specific questions addressed in this study will be: (1) What is the relative proportion of seral versus persistent aspen stands in different regions of Colorado and how does this vary across the State? (2) How do topography, elevation, soil and disturbance history influence aspen’s persistence? And, (3) What are the inter-stand dynamics associated with persistent versus seral aspen stands? During the first year of what is expected to be a multi-year project, we have focused on Grand Mesa and White River National Forests.

Historic Range of Variability Assessments for Pike, San Isabel, Arapaho, Roosevelt, Grand Mesa, Routt, and White River National Forests.
Sponsor: U.S.D.A. Forest Service. 1999-2006.

Since 1999, under a series of Cooperative Agreements with Region 2 (Colorado and Wyoming) of the USDA Forest Service, we have been producing reports on “Historic Range of Variability of Forest Ecosystems” for each National Forest in central and northern Colorado. These reports examine changes in forest conditions in relation to fire history, insect pest outbreaks, land use and climatic variation over the past c. 400 years. The aim of each report is to synthesize scientific knowledge, both published literature and unpublished data, that can inform resource planning and forest policy discussions from the perspective of how and why these forest ecosystems have changed in recent centuries. Each draft report is peer reviewed by a panel appointed by the Ecological Society of America and is published by the Colorado Forest Research Institute under an agreement with the Regional Office of the USDA Forest Service. Reports have been published for Pike-San Isabel and Arapaho-Roosevelt National Forests, and drafts are under review for Grand Mesa and Routt-White River National Forests.

Fire and landscape change in Northern Patagonia, Argentina: Integrating landscape heterogeneity, land use and climatic variability.
Sponsor: National Science Foundation, Geography Program. 2001-2005.

In the context of global climate change and increased impacts of humans on natural landscapes, increased fire occurrence is likely to be a major cause of widespread change in forested ecosystems. Although much is known about how short-term weather conditions affect the probability of fire occurrence and its intensity, much less is known about how the history of land use and the heterogeneity of the landscape affect the potential for both fire spread and ecosystem response to fire. In Northern Patagonia, Argentina, this project addresses the following key questions: 1) How does landscape heterogeneity resulting from recent (i.e. past c. 200 years) disturbance history (mainly fires) affect the spread of fire and subsequent post-fire vegetation and fuel changes? 2) What are the effects of climatic conditions on post-fire vegetation recovery, especially tree regeneration? 3) What are the effects of livestock (i.e. land use) on the critical, early phases of post-fire vegetation and fuels recovery? These three questions are being examined through an integrated multi-scale approach to vegetation dynamics and landscape change across a range of ecosystem types from dry shrublands to wet forests. The methodology integrates broad-scale spatial analyses of vegetation and fire patterns derived from historical aerial photographs and satellite images with detailed field studies of disturbance history based on tree-ring samples. These methods are combined with plot-scale experimental manipulation of moisture availability and herbivory by livestock to simulate the effects of climatic variation and land use on vegetation recovery after fire.

This research is advancing a long-term research program (initiated in 1985) on how natural disturbance, climatic variability and human activities have and continue to alter Northern Patagonian landscapes. The expected results will quantify relationships of fire behavior and effects to landscape heterogeneity at spatial and temporal scales useful for resource managers. The results will also provide a strong empirical basis for realistic application of spatial landscape-models to predicting fire behavior and fire effects in this landscape. The patterns and causal mechanisms identified in this study will guide similar approaches to understanding and predicting the ecological effects of fire, livestock, and climatic variability in other landscapes.

Forest dynamics and a massive bamboo flowering in the southern Andes.
Sponsor: National Geographic Society. 2002-2003

In November 2000 a massive flowering of the bamboo Chusquea culeou occurred in the Andes of southern Argentina and adjacent parts of Chile at c. 40°S lat. This flowering event affected most of the Andean forests over a 120 km north-south extent, and is the first massive flowering of this keystone species since 1940. A major population irruption of seed-eating rodents followed the flowering event and resulted in an outbreak of the hanta-virus in the human population. These tall bamboos dominate forest understories and are a major source of forage for native and introduced herbivores. The bamboos greatly impede tree regeneration, and, consequently, the life history of the bamboo is a controlling factor of forest dynamics at a regional scale. The focus of the research is on how the withering of the bamboo may be a window of opportunity for the regeneration of the shade-intolerant tree species that dominate these forests. We have installed permanent plots and animal exclosures to examine the effects of the bamboo flowering event on tree regeneration across five forest types, in distinct structural types (young closed canopy stands vs. old-growth stands with treefall gaps), and under differing conditions of herbivory. The research is also providing baseline data on the genetic structure of the bamboo populations in relation to isolation due to geographical location as well as timing of massive flowering.


RECENT NSF DISSERTATION IMPROVEMENT AWARDS

Cross-scale assessment of spatiotemporal patterns and drivers of fire effects in mixed-severity fire regime forests of the Northern Rockies. Cameron Naficy. 2013-2015.

Spatial and temporal variability of post-fire conifer regeneration in lower treeline forests of the U.S. Rocky Mountains.  Monica Rother. 2012-2014.

Climate variability and the susceptibility of Engelmann spruce to spruce beetle (Dendroctonus rufipennis) outbreaks in northwestern Colorado.  Sarah Hart. 2012-2014.

Mountain pine beetle and fire influences on the regeneration of lodgepole pine in northern Colorado. Teresa Chapman. 2010-2012.

Spatio-temporal variability of ponderosa pine susceptibility to mountain pine beetle in the Colorado Front Range. Meredith Gartner. 2010-2012.

Effects of climate variation on tree mortality across spatially heterogeneous subalpine forest landscapes in the Front Range of Colorado. Jeremy M. Smith. 2008-2010.

Causes and consequences of forest dieback in temperate rainforests across western Patagonia: A multiscale approach. Andres Holz. 2006-2007.

Environmental heterogeneity and insect outbreaks in Patagonian forests. Juan Paritsis. 2006-2007.

The historic range of variability of ponderosa pine in the northern Colorado Front Range: Past fire types and fire effects. Rosemary Sherriff. 2002-2003.

A multiscale analysis of natural and human influences on the variability of subalpine forest fire history in Rocky Mountain National Park. Jason Sibold. 2003-2004.

The effects of climate and disturbance variation on post-fire regeneration of Madrean pine-oak forests in Mexico’s Sierra Madre Occidental. Stacy Drury. 2002-2003.


CURRENT AND RECENT POSTDOC FELLOWSHIPS

Spruce beetle and fire interactions under climate change and adaptive forest management in subalpine forests of northern Colorado, USA .  Christian Temperli.  Swiss National Science Foundation. 2013-2014.

Wildfire Regime Shifts in Southern South America from Tree-ring Reconstructed Fire History Networks: Climatic Controls, Land Use, and Ecological Feedbacks. Andres Holz. University of Colorado Chancellor’s Postdoctoral Fellowship and NSF. 2010-2011.

Wildfire Regime Shifts in Southern South America from Tree-ring Reconstructed Fire History Networks: Climatic Controls, Land Use, and Ecological Feedbacks. Juan Paritsis. University of Colorado Chancellor’s Postdoctoral Fellowship and NSF. 2010-2011.

Fire risk and forest restoration in the wildland urban interface of the Colorado Front Range. Tania Schoennagel. David H. Smith Conservation Fellowship. 2006-2008.

Disturbance interactions in subalpine forests of northwestern Colorado. Dominik Kulakowski. Supported by the USDA Forest Service, NSF, and the Joint Fire Science Program. 2002-2007

Impact of drought and competitive interactions on tree growth and episodic tree mortality in subalpine forests of northern Colorado. Christof Bigler. Swiss National Science Foundation. 2004-2005.

Regional and local influences on climatically sensitive disturbance in the Rocky Mountains. Tania Schoennagel. NSF Postdoctoral Fellowship in Biological Informatics. 2003-2005.

Disturbance and dynamics of Nothofagus forests in southern Chile: William Pollman, supported by the German science agency (DAAD). 2002-2004.


DISSERTATIONS AND THESES COMPLETED THROUGH THE LAB

2013

Influence of climate variability on radial growth of Nothofagus pumilio near altitudinal treeline in the Andes of northern Patagonia, Chile. Claudio Alvarez (M.A.).  

2012

An examination of background tree mortality and mountain pine beetle disturbance in subalpine forests of the Front Range of Colorado, USA. Jeremy Smith (Ph.D.). 

2009

Spatio-temporal patterns of mountain pine beetle activity in lodgepole and ponderosa pines of the southern Rocky Mountains: influences of climate and habitat heterogeneity. Teresa B. Chapman (M.A.).

Climatic and human influences on fire regimes and forest dynamics in temperate
rainforests in southern Chile. Andres Holz (Ph.D.).

2009 Temperature influences on phenology and population growth of mountain pine beetle populations in northern Colorado. Kerry E.W. Malm (M.A.).

Insect defoliator outbreaks and environmental heterogeneity in Nothofagus forests in the Patagonian Andes. Juan Paritsis (Ph.D.).

2008

Fire history of ponderosa pine-dominated forests in the Colorado Front Range: Elevation, topography and land-use. Meredith H. Albright (M.A.).

2007

Characterizing historic fire regimes from understory vegetation composition in ponderosa pine-dominated forests of the northern Colorado Front Range. Robin Keith (M.A.).

Forest fuel mapping and strategic wildfire mitigation in the montane zone of Boulder County, Colorado. Kevin Krasnow (M.A.).

2006

Effects of climate and disturbance on Madrean pine-oak forests in Mexico's Sierra Madre Occidental; Stacy Drury (Ph.D.).

2005

A multi-scale analysis of natural and human influences on the variability of subalpine forest fire history in Rocky Mountain National Park; Jason Sibold (Ph.D.).

2004

Regeneration dynamics of persistent quaking aspen (Populus tremuloides) in western Colorado; Brian P. Kurzel (M.A.).

Tree regeneration responses to Chusquea montana bamboo dieback in subalpine forests in the southern Andes; Andrés Holz (M.A.).

The role of recent climatic variability on episodic Pinus ponderosa recruitment patterns along the forest-grassland ecotone of northern Colorado; Kevin League (M.A.).

Historic range of variability and stand development in pinon-juniper woodlands of western Colorado; Karen S. Eisenhart (Ph.D).

The historic range of variability of ponderosa pine in the northern Colorado Front Range: Past fire types and fire effects; Rosemary Sherriff (Ph.D.).

Modeling wildfire mitigation and ecological restoration in the wildland-urban interface: A study of the montane zone of the Colorado Front Range; Rutherford V. Platt (Ph.D.).

2002

Effects of exotic pine on Paramo grasslands in the Ecuadorian Andes; Kathleen Farley (Ph.D.).

Fire history of Araucaria-Nothofagus forests in the Andean Cordillera of South-Central Chile; Mauro Gonzalez (Ph.D.).

Interactions among natural disturbances in subalpine forests in northwestern Colorado; Dominik Kulakowski (Ph.D.).

2001

The forest fire regime of an upper montane and subalpine forest, Wild Basin, Rocky Mountain National Park; Jason Sibold (M.A.).

2000

Climatic and human influences on fire regimes in Pike National Forest; Joseph Donnegan (Ph.D.).

Fire history at high elevation in the Colorado Front Range; Rosemary Sherriff (M.A.).

The dynamics of alpine treelines in the southern Andes; Lori D. Daniels (Ph.D.).

1999

Influences of dieback of the bamboo Chusquea quila on tree regeneration in canopy gaps in south-centra Chile; Mauro Gonzalez (M.A.).

Disturbances and tree species diversity along the elevational gradient of a subtropical montane forest of NW Argentina; Ricardo Grau (Ph.D.).

Dendrochronological identification of spruce bark beetle outbreaks in northwestern Colorado; Karen S. Eisenhart (M.A.).

1997

The impact of flood frequency, permafrost distribution, and climate variation on a northern treeline floodplain in Alaska; Alison E. Arians (Ph.D.).

1996

A dendrochronological history of western spruce budworm (Choristoneura occidentalis Freeman) infestations and outbreaks in the northern Colorado Front Range; Steven W. Shimek (M.A.).

1995

Disturbance regimes and regeneration dynamics of upper montane forests and páramos in the southern Ecuadorian Andes; Philip L. Keating (Ph.D.).

Climatic influences on forest dynamics along the forest-steppe ecotone in northern Patagonia; Ricardo Villalba (Ph.D.).

1994

Fire regime variation along a northern Patagonian forest-steppe gradient: Stand and landscape response; Thomas Kitzberger (Ph.D.).

1993

Climatic and disturbance factors influencing Pinus ponderosa stand structure near the forest/grassland ecotone in the Colorado Front Range; Joy N. Mast (Ph.D.).

1992

The use of remote sensing techniques in the old-growth spruce-fir forests in the Rocky Mountains; Elizabeth M. Nel (M.A.).

1991

A dendrochronological method of studying tree mortality patterns; Joy Nystrom Mast (M.A.).

The dynamics and disturbance regimes of Fitzroya cupressoides forests in the Andes of south-central Chile; Antonio Lara (Ph.D.).

The regeneration dynamics of Araucaria araucana in the southern Andes; Bruce R. Burns (Ph.D.).

1990

Biogeography and ecology of timberline forest in north-central Peru; Ken Young (Ph.D.).

Fire history of a Ponderosa pine/Douglas fir forest in the Colorado Front Range; David Goldblum (M.A.).

Stand response and landscape response to western spruce budworm and Douglas-fir bark beetle outbreaks, Colorado Front Range; Keith Hadley (Ph.D.).

1989

The response of understory vegetation to major canopy disturbance in the subalpine forests of Colorado; Marion Reid (M.A.).

Structural dynamics of a pine forest in the American southwest under chronic human disturbance; Melissa Savage (Ph.D.).

1988

Successional change in vegetation and soils of southeast Alaska; Lee Klinger (Ph.D.).

1987

Social dominance and the winter distribution of the Dark-eyed Junco (Junco hyemalis); Peter Yaukey (M.A.).

Ecology of bamboos and their role in forest dynamics in the Wolong Natural Reservem Sichuan, China; Alan Taylor (Ph.D.).

1986

Early forest succession on abandoned agricultural fields on the loess bluffs of western Tennessee; David Shankman (Ph.D.).

1985

Vegetation changes associated with land use practices in Mbeya region, Tanzania; Salome Kigongo Mashalla (Ph.D.).

1984

Influences of snow persistence on the regeneration of Engelmann spruce and subalpine fir, Colorado Front Range; Christopher Daly (M.A.).

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