Forest health and drought response Active
Tree mortality during extreme drought
view from Beetle Rock, Sequoia National Park, California
Characteristic bark beetle galleries
engraver beetle response to California’s extreme drought prove deadly to this white fir
Forests provide society with economically important and often irreplaceable goods and services, such as wood products, carbon sequestration, clean water, biodiversity, and recreational opportunities. Yet hotter droughts (droughts in which unusually high temperatures exacerbate the effects of low precipitation) are projected to increase in frequency and intensity in coming decades, potentially threatening forest sustainability. Using a number of complementary data sets, this project treats California’s recent hotter drought as a potential preview of the future, with the ultimate goal of providing forest managers with the information and adaptation tools they need to increase forest resistance and resilience to extreme droughts of the future.
Statement of Problem:
Ongoing global changes – particularly interacting changes in climate, land use, and disturbance regimes – are rapidly altering forests, often in undesirable ways. Such changes have been particularly evident in the western United States. This project explores the effects of climatic drivers on forest vegetation, ecological disturbance processes, mountain hydrology, and the coupled ecohydrological responses that determine vulnerability of western U.S. mountain landscapes to change.
Why this Research is Important:
Forests sequester the majority of the terrestrial biosphere’s carbon, making them key components of the global carbon cycle. For society to anticipate, mitigate, and adapt to these increasing threats to forests, we must improve our ability to understand and forecast forest response to environmental changes and management actions. We thus work closely with forest managers – particularly in the National Park Service and U.S. Forest Service – to provide concepts and tools for wise management of the nation’s forests. Our primary insights come from intensive, place-based study of a globally unique network of forest research plots in California’s Sierra Nevada mountain range, in which the fates of tens of thousands of trees have been followed for up to 36 years. Insights from this network, in turn, catalyze regional and global syntheses.
Linked to the Western Mountain Initiative (WMI) since 2003, this project explores effects of climatic drivers on forest vegetation, ecological disturbance processes, mountain hydrology, and the coupled ecohydrological responses that determine vulnerability of western U.S. mountain landscapes to change (see figure below).
Objective(s):
The effects of California’s extreme 2012-2016 drought were exacerbated by abnormally high temperatures, resulting in historically unprecedented tree mortality. To capture scientific information needed to prepare forest managers for similar events in the future, we launched the Leaf to Landscape project in 2014, with core funding from USGS, NPS, and USFS. Our 2014-2017 collection of “perishable” data was coordinated across spatial scales, from tree leaves to entire forested landscapes. Our globally-unique network of permanent forest plots in the Sierra Nevada has been a key component of this interdisciplinary effort.
Our primary goal for the next five years is to apply our existing Leaf to Landscape data and continued documentation of forest drought response and recovery to provide forest managers with key information and tools, as outlined the following six objectives:
Objective 1: Create and validate empirically derived, species-specific forest vulnerability maps, letting the trees themselves reveal which parts of the forested landscape are likely to be most vulnerable to future hotter droughts.
Objective 2: (i) Empirically identify areas that served as hydrologic refugia during the drought, (ii) quantify the extent to which they protected tree species, and (iii) determine whether tree species differed in the extent to which refugia protected them.
Objective 3: Provide a first real validation test of a state-of-the-art forest vulnerability model, determining how well it predicted actual patterns of tree mortality during the hotter drought.
Objective 4: Empirically quantify the effectiveness – or lack thereof – of past forest treatments in increasing tree survival during extreme drought.
Objective 5: Determine the species-specific timing, magnitude, and nature of lagged tree mortality following extreme drought.
Objective 6: Create and validate empirically derived giant sequoia vulnerability maps, and determine the role of bark beetles in drought-induced sequoia mortality.
The Western Mountain Initiative (WMI)
Below are publications associated with this project.
Response of western mountain ecosystems to climatic variability and change: A collaborative research approach
Shifting environmental foundations: The unprecedented and unpredictable future: Chapter 4
Responding to climate change: A toolbox of management strategies: Chapter 11
Guiding concepts for park and wilderness stewardship in an era of global environmental change
Widespread increase of tree mortality rates in the Western United States
Options for national parks and reserves for adapting to climate change
Spatial elements of mortality risk in old-growth forests
Preliminary review of adaptation options for climate-sensitive ecosystems and resources. A report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research
Naturalness and beyond: Protected area stewardship in an era of global environmental change
Climate change and forests of the future: Managing in the face of uncertainty
The relationship between tree growth patterns and likelihood of mortality: A study of two tree species in the Sierra Nevada
Response of western mountain ecosystems to climatic variability and change: The Western Mountain Initiative
- Overview
Forests provide society with economically important and often irreplaceable goods and services, such as wood products, carbon sequestration, clean water, biodiversity, and recreational opportunities. Yet hotter droughts (droughts in which unusually high temperatures exacerbate the effects of low precipitation) are projected to increase in frequency and intensity in coming decades, potentially threatening forest sustainability. Using a number of complementary data sets, this project treats California’s recent hotter drought as a potential preview of the future, with the ultimate goal of providing forest managers with the information and adaptation tools they need to increase forest resistance and resilience to extreme droughts of the future.
Statement of Problem:
Ongoing global changes – particularly interacting changes in climate, land use, and disturbance regimes – are rapidly altering forests, often in undesirable ways. Such changes have been particularly evident in the western United States. This project explores the effects of climatic drivers on forest vegetation, ecological disturbance processes, mountain hydrology, and the coupled ecohydrological responses that determine vulnerability of western U.S. mountain landscapes to change.
Why this Research is Important:
Forests sequester the majority of the terrestrial biosphere’s carbon, making them key components of the global carbon cycle. For society to anticipate, mitigate, and adapt to these increasing threats to forests, we must improve our ability to understand and forecast forest response to environmental changes and management actions. We thus work closely with forest managers – particularly in the National Park Service and U.S. Forest Service – to provide concepts and tools for wise management of the nation’s forests. Our primary insights come from intensive, place-based study of a globally unique network of forest research plots in California’s Sierra Nevada mountain range, in which the fates of tens of thousands of trees have been followed for up to 36 years. Insights from this network, in turn, catalyze regional and global syntheses.
Linked to the Western Mountain Initiative (WMI) since 2003, this project explores effects of climatic drivers on forest vegetation, ecological disturbance processes, mountain hydrology, and the coupled ecohydrological responses that determine vulnerability of western U.S. mountain landscapes to change (see figure below).
Objective(s):
The effects of California’s extreme 2012-2016 drought were exacerbated by abnormally high temperatures, resulting in historically unprecedented tree mortality. To capture scientific information needed to prepare forest managers for similar events in the future, we launched the Leaf to Landscape project in 2014, with core funding from USGS, NPS, and USFS. Our 2014-2017 collection of “perishable” data was coordinated across spatial scales, from tree leaves to entire forested landscapes. Our globally-unique network of permanent forest plots in the Sierra Nevada has been a key component of this interdisciplinary effort.
Our primary goal for the next five years is to apply our existing Leaf to Landscape data and continued documentation of forest drought response and recovery to provide forest managers with key information and tools, as outlined the following six objectives:
Objective 1: Create and validate empirically derived, species-specific forest vulnerability maps, letting the trees themselves reveal which parts of the forested landscape are likely to be most vulnerable to future hotter droughts.
Objective 2: (i) Empirically identify areas that served as hydrologic refugia during the drought, (ii) quantify the extent to which they protected tree species, and (iii) determine whether tree species differed in the extent to which refugia protected them.
Objective 3: Provide a first real validation test of a state-of-the-art forest vulnerability model, determining how well it predicted actual patterns of tree mortality during the hotter drought.
Objective 4: Empirically quantify the effectiveness – or lack thereof – of past forest treatments in increasing tree survival during extreme drought.
Objective 5: Determine the species-specific timing, magnitude, and nature of lagged tree mortality following extreme drought.
Objective 6: Create and validate empirically derived giant sequoia vulnerability maps, and determine the role of bark beetles in drought-induced sequoia mortality.
- Science
The Western Mountain Initiative (WMI)
Western Mountain Initiative (WMI) is a long-term collaboration between FORT, WERC, NOROCK, USFS, NPS, LANL, and universities worldwide to address changes in montane forests and watersheds due to climate change. Current emphases include altered forest disturbance regimes (fire, die-off, insect outbreaks) and hydrology; interactions between plants, water, snow, nutrient cycles, and climate; and... - Publications
Below are publications associated with this project.
Filter Total Items: 42Response of western mountain ecosystems to climatic variability and change: A collaborative research approach
No abstract available.AuthorsDavid L. Peterson, Craig D. Allen, Jill S. Baron, Daniel B. Fagre, Donald McKenzie, Nathan L. Stephenson, Andrew G. Fountain, Jeffrey A. Hicke, George P. Malanson, Dennis S. Ojima, Christina L. Tague, Phillip J. van MantgemShifting environmental foundations: The unprecedented and unpredictable future: Chapter 4
As described in Chapter 2, protected area managers have been directed, through statutes and agency policy, to preserve natural conditions in parks and wilderness. Although preserving naturalness has always been a challenge for managers, there has never been much question about whether this is the right thing to do. But given what is known now about the pace and magnitude of ongoing global changes,AuthorsNathan L. Stephenson, Constance I. Millar, David ColeResponding to climate change: A toolbox of management strategies: Chapter 11
Climate change and its effects are writ large across the landscape and in the natural and cultural heritage of parks and wilderness. They always have been and always will be. The sculpted walls of Yosemite National Park and the jagged scenery of the Sierra Nevada wilderness would not be as spectacular if periods of glaciation had not been followed by periods of deglaciation. High biodiversity in fAuthorsDavid Cole, Nathan L. Stephenson, Constance I. MillarGuiding concepts for park and wilderness stewardship in an era of global environmental change
The major challenge to stewardship of protected areas is to decide where, when, and how to intervene in physical and biological processes, to conserve what we value in these places. To make such decisions, planners and managers must articulate more clearly the purposes of parks, what is valued, and what needs to be sustained. A key aim for conservation today is the maintenance and restoration of bAuthorsRichard J. Hobbs, David N. Cole, Laurie Yung, Erika S. Zavaleta, Gregory H. Aplet, F. Stuart Chapin, Peter B. Landres, David J. Parsons, Nathan L. Stephenson, Peter S. White, David M. Graber, Eric S. Higgs, Constance I. Millar, John M. Randall, Kathy A. Tonnessen, Stephen WoodleyWidespread increase of tree mortality rates in the Western United States
Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years among regions. IncreasesAuthorsP. J. van Mantgem, N.L. Stephenson, J.C. Byrne, L.D. Daniels, J.F. Franklin, P.Z. Fule, M. E. Harmon, A.J. Larson, Joseph M. Smith, A.H. Taylor, T.T. VeblenOptions for national parks and reserves for adapting to climate change
Past and present climate has shaped the valued ecosystems currently protected in parks and reserves, but future climate change will redefine these conditions. Continued conservation as climate changes will require thinking differently about resource management than we have in the past; we present some logical steps and tools for doing so. Three critical tenets underpin future management plans andAuthorsJill S. Baron, Lance Gunderson, Craig D. Allen, Erica Fleishman, Donald McKenzie, Laura A. Meyerson, Jill Oropeza, Nathan L. StephensonSpatial elements of mortality risk in old-growth forests
For many species of long-lived organisms, such as trees, survival appears to be the most critical vital rate affecting population persistence. However, methods commonly used to quantify tree death, such as relating tree mortality risk solely to diameter growth, almost certainly do not account for important spatial processes. Our goal in this study was to detect and, if present, to quantify the relAuthorsAdrian Das, John Battles, Phillip J. van Mantgem, Nathan L. StephensonPreliminary review of adaptation options for climate-sensitive ecosystems and resources. A report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research
Climate variables are key determinants of geographic distributions and biophysical characteristics of ecosystems, communities, and species. Climate change is therefore affecting many species attributes, ecological interactions, and ecosystem processes. Because changes in the climate system will continue into the future regardless of emissions mitigation, strategies for protecting climate-sensitiveAuthorsJill S. Baron, Brad Griffith, Linda A. Joyce, Peter Kareiva, Brian D. Keller, Margaret A. Palmer, Charles H. Peterson, J. Michael ScottNaturalness and beyond: Protected area stewardship in an era of global environmental change
For most large U.S. parks and wilderness areas, enabling legislation and management policy call for preservation of these protected areas unimpaired in perpetuity. Central to the notions of protection, preservation, and unimpairment has been the concept of maintaining “naturalness,” a condition imagined by many to persist over time in the absence of human intervention. As will be discussed below iAuthorsDavid N. Cole, Laurie Yung, Erika S. Zavaleta, Gregory H. Aplet, F. Stuart Chapin, David M. Graber, Eric S. Higgs, Richard J. Hobbs, Peter B. Landres, Constance I. Millar, David J. Parsons, John M. Randall, Nathan L. Stephenson, Kathy A. Tonnessen, Peter S. White, Stephen WoodleyClimate change and forests of the future: Managing in the face of uncertainty
We offer a conceptual framework for managing forested ecosystems under an assumption that future environments will be different from present but that we cannot be certain about the specifics of change. We encourage flexible approaches that promote reversible and incremental steps, and that favor ongoing learning and capacity to modify direction as situations change. We suggest that no single solutAuthorsC. I. Millar, N.L. Stephenson, S.L. StephensThe relationship between tree growth patterns and likelihood of mortality: A study of two tree species in the Sierra Nevada
We examined mortality of Abies concolor (Gord. & Glend.) Lindl. (white fir) and Pinus lambertiana Dougl. (sugar pine) by developing logistic models using three growth indices obtained from tree rings: average growth, growth trend, and count of abrupt growth declines. For P. lambertiana, models with average growth, growth trend, and count of abrupt declines improved overall prediction (78.6% dead tAuthorsA.J. Das, J. J. Battles, N.L. Stephenson, P. J. van MantgemResponse of western mountain ecosystems to climatic variability and change: The Western Mountain Initiative
Mountain ecosystems within our national parks and other protected areas provide valuable goods and services such as clean water, biodiversity conservation, and recreational opportunities, but their potential responses to expected climatic changes are inadequately understood. The Western Mountain Initiative (WMI) is a collaboration of scientists whose research focuses on understanding and predictinAuthorsNathan L. Stephenson, Dave Peterson, Daniel B. Fagre, Craig D. Allen, Donald McKenzie, Jill Baron, Kelly O'Brian