Craig D Allen, Ph.D. (Former Employee)
Science and Products
Effects of disturbance and drought on the forests and hydrology of the Southern Rocky Mountains
Climate-related forest disturbances, particularly drought-induced tree mortality and large, high-severity fires from increasingly warm and dry conditions, are altering forest ecosystems and the ecosystem services society depends on (e.g., water supplies). Our research combines long-term place-based ecological data, diverse methods (e.g., paleo, remote-sensing), and networking approaches to...
The New Mexico Landscapes Field Station
The New Mexico Landscapes Field Station is a place-based, globally-connected, ecological research group that studies and interprets ecosystem and wildlife dynamics, working with land managers and community leaders to deliver solutions that foster the linked health of human and natural systems.
Our partnerships, and co-location, with land management agencies provide us with opportunities...
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...
Tree Mortality Patterns and Processes
Natural climatic variability, including episodic droughts, has long been known to trigger accelerated tree mortality in forests worldwide, including in the Southwest U.S. Scientific understanding of the process drivers and spatial patterns of tree mortality is surprisingly limited, constraining our ability to model forest responses to projected climate changes. The onset of regional drought...
Long-term, Place-based, Ecological Monitoring
For over 30 years we have monitored the ecosystem dynamics of the mesas and mountains of northern New Mexico, based at Bandelier National Monument and the New Mexico state office for the Bureau of Land Management. Our work provides land managers and scientists with diverse information on landscape responses to climate and disturbances (fire, drought, insects) such as vegetation and erosion...
Post-fire Recovery Patterns in Southwestern Forests
High-severity crown fires in Southwestern dry-conifer forests — resulting from fire suppression, fuel buildups, and drought — are creating large treeless areas that are historically unprecedented in size. These recent stand-replacing fires have reset extensive portions of Southwest forest landscapes, fostering post-fire successional vegetation that can alter ecological recovery trajectories...
New Mexico Dendroecology Lab
Using tree ring analysis as a primary research tool, we conduct landscape-scale ecological research that focuses on the effects of climate variability on forest ecology, fire ecology, and ecohydrology.
We are the only tree-ring lab in New Mexico, working in close collaboration with Bandelier National Monument and Emeritus Regents’ Professor Dr. Thomas Swetnam. However, we were not the...
Seeing the Forest and the Trees
The recent recipient of two major awards, Craig D. Allen, a research ecologist with the U.S. Geological Survey Fort Collins Science Center, has loved trees since childhood. He is now considered an expert of world renown on the twin phenomena of forest changes and tree mortality resulting from climate warming and drought, and in 2010 was twice recognized for his scientific contributions....
Valleys of fire: Historical fire regimes of forest-grassland ecotones across the montane landscape of the Valles Caldera National Preserve, New Mexico, USA
ContextMontane grasslands and forest-grassland ecotones are unique and dynamic components of many landscapes, but the processes that regulate their dynamics are difficult to observe over ecologically relevant time spans.ObjectivesWe aimed to demonstrate the efficacy of using grassland-forest ecotone trees to reconstruct spatial and temporal...
Dewar, J. J.; Falk, Donald A.; Swetnam, T. W.; Baisan, C. H.; Allen, Craig D.; Parmenter, R. R.; Margolis, EllisMortality predispositions of conifers across western USA
Conifer mortality rates are increasing in western North America, but the physiological mechanisms underlying this trend are not well understood.We examined tree‐ring‐based radial growth along with stable carbon (C) and oxygen (O) isotope composition (δ13C and δ18O, respectively) of dying and surviving conifers at eight old‐growth forest sites...
Wang, Wenzhi; English, Nathan B.; Grossiord, Charlotte; Gessler, Arthur; Das, Adrian; Stephenson, Nathan L.; Baisan, Christopher H.; Allen, Craig D.; McDowell, Nate G.Pervasive shifts in forest dynamics in a changing world
Forest dynamics arise from the interplay of environmental drivers and disturbances with the demographic processes of recruitment, growth, and mortality, subsequently driving biomass and species composition. However, forest disturbances and subsequent recovery are shifting with global changes in climate and land use, altering these dynamics....
McDowell, Nate G.; Allen, Craig D.; Anderson-Teixeira, Kristina J.; Aukema, Brian H.; Bond-Lamberty, Ben; Chini, Louise; Clark, James S.; Dietze, Michael; Grossiord, Charlotte; Hanbury-Brown, Adam; Hurtt, George C.; Jackson, Robert B.; Johnson, Daniel J.; Kueppers, Lara; Lichstein, Jeremy W.; Ogle, Kiona; Poulter, Benjamin; Pugh, Thomas A. M.; Seidl, Rupert; Turner, Monica G.; Uriarte, María; Walker, Anthony P.; Xu, ChonggangSimulated increases in fire activity reinforce shrub conversion in a southwestern US forest
Fire exclusion in historically frequent-fire forests of the southwestern United States has altered forest structure and increased the probability of high-severity fire. Warmer and drier conditions, coupled with dispersal distance limitations, are impeding tree seedling establishment and survival following high-severity fire. High-severity patches...
Keyser, Alisa R.; Krofchek, Dan J.; Remy, Cécile C.; Allen, Craig D.; Hurteau, Matthew D.A shrubbier future: Forest transformation in the eastern Jemez Mountains
No abstract available.
Allen, Craig D.Spatio-temporal variability of human-fire interactions on the Navajo Nation
Unraveling the effects of climate and land-use on historical fire regimes provides important insights into broader human-fire-climate dynamics, which are necessary for ecologically-based forest management. We developed a spatial human land-use model for Navajo Nation forests across which we sampled a network of tree-ring fire history sites to...
Guiterman, Christopher H.; Margolis, Ellis; Baisan, Christopher H.; Falk, Donald A.; Allen, Craig D.; Swetnam, Thomas W.Rapid broad-scale ecosystem changes and their consequences for biodiversity
Biodiversity contributes to and depends on ecosystem structure and associated function. Ecosystem structure, such as the amount and type of tree cover, influences fundamental abiotic variables such as near-ground incoming solar radiation (e.g., Royer et al. 2011), which in turn affects species and associated biodiversity (e.g., Trotter et al. 2008...
Breshears, David D.; Field, Jason P.; Law, Darin J.; Villegas, Juan C.; Allen, Craig D.; Cobb, Neil S.; Bradford, John B.Mechanisms of a coniferous refugium persistence under drought and heat
Predictions of warmer droughts causing increasing forest mortality are becoming abundant, yet few studies have investigated the mechanisms of forest persistence. To examine the resistance of forests to warmer droughts, we used a five-year precipitation reduction (~45% removal), heat (+4 °C above ambient) and combined drought and heat experiment in...
McDowell, Nate G.; Grossiord, Charlotte; Adams, Henry D.; Pinzón-Navarro, Sara; MacKay, D. Scott; Breshears, Dave; Allen, Craig D.; Borrego, Isaac; Dickman, L. Turin; Collins, Adam D.A statement of common ground regarding the role of wildfire in forested landscapes of the western United States
For millennia, wildfires have markedly influenced forests and non-forested landscapes of the western United States (US), and they are increasingly seen as having substantial impacts on society and nature. There is growing concern over what kinds and amounts of fire will achieve desirable outcomes and limit harmful effects on people and nature....
Moritz, Max A.; Topik, Chris; Allen, Craig D.; Hessburg, Paul F.; Morgan, Penelope; Odion, Dennis C.; Veblen, Thomas T.; McCullough, Ian M.Limits to ponderosa pine regeneration following large high-severity forest fires in the United States Southwest
High-severity fires in dry conifer forests of the United States Southwest have created large (>1000 ha) treeless areas that are unprecedented in the regional historical record. These fires have reset extensive portions of Southwestern ponderosa pine (Pinus ponderosa Lawson & C. Lawson var. scopulorum Engelm.) forest landscapes. At least two...
Haffey, Collin; Sisk, Thomas D.; Allen, Craig D.; Thode, Andrea E.; Margolis, EllisDrivers and mechanisms of tree mortality in moist tropical forests
Tree mortality rates appear to be increasing in moist tropical forests (MTFs) with significant carbon cycle consequences. Here, we review the state of knowledge regarding MTF tree mortality, create a conceptual framework with testable hypotheses regarding the drivers, mechanisms and interactions that may underlie increasing MTF mortality rates,...
McDowell, Nate G.; Allen, Craig D.; Anderson‐Teixeira, Kristina; Brando, Paulo M.; Brienen, Roel; Chambers, Jeff; Christoffersen, Brad; Davies, Stuart J.; Doughty, Chris; Duque, Alvaro; Espirito-Santo, Fernando; Fisher, Rosie A.; Fontes, Clarissa G.; Galbraith, David; Goodsman, Devin; Grossiord, Charlotte; Hartmann, Henrik; Holm, Jennifer; Johnson, Daniel J.; Kassim, Abd. Rahman; Keller, Michael; Koven, Charles; Kueppers, Lara; Kumagai, Tomo'omi; Malhi, Yadvinder; McMahon, Sean M.; Mencuccini, Maurizio; Meir, Patrick; Moorcroft, Paul R.; Muller-Landau, Helene C.; Phillips, Oliver L.; Powell, Thomas M.; Sierra, Carlos A.; Sperry, John; Warren, Jeff; Xu, Chonggang; Xu, XiangtaoResearch frontiers for improving our understanding of drought‐induced tree and forest mortality
Accumulating evidence highlights increased mortality risks for trees during severe drought, particularly under warmer temperatures and increasing vapour pressure deficit (VPD). Resulting forest die‐off events have severe consequences for ecosystem services, biophysical and biogeochemical land–atmosphere processes. Despite advances in monitoring,...
Hartmann, Henrik; Moura, Catarina; Anderegg, William R. L.; Ruehr, Nadine K.; Salmon, Yann; Allen, Craig D.; Arndt, Stefan K.; Breshears, David D.; Davi, Hendrik; Galbraith, David; Ruthrof, Katinka X.; Wunder, Jan; Adams, Henry D.; Bloemen, Jasper; Cailleret, Maxime; Cobb, Richard; Gessler, Arthur; Grams, Thorsten E. E.; Jansen, Steven; Kautz, Markus; Lloret, Francisco; O’Brien, MichaelPre-USGS Publications
Fort Collins Science Center Scientists have strong presence at AGU Fall Meeting 2020
Fort Collins Science Center scientists had multiple presentations and poster submissions, as well as one award, at the American Geophysical Union (AGU) Fall Meeting 2020. The Meeting was the largest worldwide virtual conference in the Earth and space sciences, with over 20,000 attendees.
Land Change Science Seminar
Changing Drought Extremes as a Growing Stressor of Eco-Hydro-Socio-Systems: Strategic Opportunities & Challenges for Multi-Disciplinary USGS Research