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Climate change

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Articles 91 - 120 of 164

Full-Text Articles in Forest Sciences

Infrared Heater System For Warming Tropical Forest Understory Plants And Soils, Bruce Kimball, Auro M. Alonso-Rodriguez, Molly A. Cavaleri, Sasha Reed, Grizelle Gonzalez, Tana E. Wood Feb 2018

Infrared Heater System For Warming Tropical Forest Understory Plants And Soils, Bruce Kimball, Auro M. Alonso-Rodriguez, Molly A. Cavaleri, Sasha Reed, Grizelle Gonzalez, Tana E. Wood

Michigan Tech Publications, Part 1

The response of tropical forests to global warming is one of the largest uncertainties in predicting the future carbon balance of Earth. To determine the likely effects of elevated temperatures on tropical forest understory plants and soils, as well as other ecosystems, an infrared (IR) heater system was developed to provide in situ warming for the Tropical Responses to Altered Climate Experiment (TRACE) in the Luquillo Experimental Forest in Puerto Rico. Three replicate heated 4‐m‐diameter plots were warmed to maintain a 4°C increase in understory vegetation compared to three unheated control plots, as sensed by IR thermometers. The equipment was …


Temperate And Tropical Forest Canopies Are Already Functioning Beyond Their Thermal Thresholds For Photosynthesis, Alida C. Mau, Sasha C. Reed, Tana E. Wood, Molly A. Cavaleri Jan 2018

Temperate And Tropical Forest Canopies Are Already Functioning Beyond Their Thermal Thresholds For Photosynthesis, Alida C. Mau, Sasha C. Reed, Tana E. Wood, Molly A. Cavaleri

Michigan Tech Publications, Part 1

Tropical tree species have evolved under very narrow temperature ranges compared to temperate forest species. Studies suggest that tropical trees may be more vulnerable to continued warming compared to temperate species, as tropical trees have shown declines in growth and photosynthesis at elevated temperatures. However, regional and global vegetation models lack the data needed to accurately represent such physiological responses to increased temperatures, especially for tropical forests. To address this need, we compared instantaneous photosynthetic temperature responses of mature canopy foliage, leaf temperatures, and air temperatures across vertical canopy gradients in three forest types: tropical wet, tropical moist, and temperate …


Dendroclimatic Analysis Of White Pine (Pinus Strobus L.) Using Long-Term Provenance Test Sites Across Eastern North America, Sophan Chhin, Ronald S. Zalesny Jr, William C. Parker, John Brissette Jan 2018

Dendroclimatic Analysis Of White Pine (Pinus Strobus L.) Using Long-Term Provenance Test Sites Across Eastern North America, Sophan Chhin, Ronald S. Zalesny Jr, William C. Parker, John Brissette

Faculty & Staff Scholarship

Background: The main objective of this study was to examine the climatic sensitivity of the radial growth response of 13 eastern white pine (Pinus strobus L.) provenances planted at seven test sites throughout the northern part of the species’ native distribution in eastern North America.

Methods: The test sites (i.e., Wabeno, Wisconsin, USA; Manistique, Michigan, USA; Pine River, Michigan, USA; Newaygo, Michigan, USA; Turkey Point, Ontario, Canada; Ganaraska, Ontario, Canada; and Orono, Maine, USA) examined in this study were part of a range-wide white pine provenance trial established in the early 1960s in the eastern United States and Canada. Principal …


Drivers Of Post-Fire Vascular Plant Regeneration In The Conifer-Dominated Boreal Forest Of Southern Northwest Territories, Alison White Jan 2018

Drivers Of Post-Fire Vascular Plant Regeneration In The Conifer-Dominated Boreal Forest Of Southern Northwest Territories, Alison White

Theses and Dissertations (Comprehensive)

In recent years, climate warming has led to an increase in the severity and frequency of naturally occurring fires in boreal ecosystems globally. In 2014, an unprecedented 3.4 million hectares of boreal forest burned in the Northwest Territories (NWT). While much research has focused on post-fire succession of serotinous tree species such as Picea mariana (black spruce) and Pinus banksiana (jack pine), the understory community of vascular plants play an important role in ecosystem functioning but less is known about the response of this component of the system to changing fire regimes. Regeneration strategies such as the ability to resprout …


Great Basin Forb Restoration: Lupine Response To Altered Precipitation Predicted By Climate Change, Andrea Jo Johnson, Kristin Hulvey, Scott Jensen, Tom Monaco Jan 2018

Great Basin Forb Restoration: Lupine Response To Altered Precipitation Predicted By Climate Change, Andrea Jo Johnson, Kristin Hulvey, Scott Jensen, Tom Monaco

Research on Capitol Hill

Abundance of native forb species is declining, leading to degraded ecosystems within the Great Basin.

Forbs provide many ecosystem functions, including wildlife habitat for species such as Sage Grouse, increased biodiversity, resistance to erosion, and protection from invasive plant species.

Climate change is predicted to affect timing, frequency, and intensity of precipitation within the Great Basin. During the fall season, precipitation is expected to increase by 30%.

Changes in precipitation will likely affect fall emergence of forbs, which is essential for overwintering and establishment.

Learning how precipitation affects forb emergence could lead to new methods that increase fall emergence and …


Growth Dynamics Of Black Spruce (Picea Mariana) Across Northwestern North America, Anastasia E. Sniderhan Jan 2018

Growth Dynamics Of Black Spruce (Picea Mariana) Across Northwestern North America, Anastasia E. Sniderhan

Theses and Dissertations (Comprehensive)

The impacts of climate change have been widely documented around the world. One of the most rapidly changing areas is the boreal forest of North America. The extent of change has been such that there have been shifts in long-standing climate-growth relationships in many boreal tree species; while the growth of many of these high-latitude forests were formerly limited by temperature, warming has increased the evapotranspirative demands such that there is widespread drought stress limiting productivity in the boreal forest. With the importance of the boreal forest as a global carbon sink, it is imperative to understand the extent of …


Estimating The Range Shift And Harvesting Intensity Of Junipers In Bhutan (Eastern Himalaya), Rinchen Namgay Nov 2017

Estimating The Range Shift And Harvesting Intensity Of Junipers In Bhutan (Eastern Himalaya), Rinchen Namgay

Theses

The authors of more than 97% of the scientific publications on climate change agree that global temperature has increased in the last six decades and is caused by human beings via emission of greenhouse gases in the atmosphere. This phenomenon has altered natural ecosystem functions, causing many species to shift to a more suitable habitat. Throughout the world, because of recent climate warming, many forms of range shift associated with climate warming has occurred. While animals can move as warming happens, plants being stationary organisms cannot move, so the difference in the distribution of different plant life stages is an …


Will Seasonally Dry Tropical Forests Be Sensitive Or Resistant To Future Changes In Rainfall Regimes?, Kara Allen, Juan Manuel Dupuy, Maria G. Gei, Catherine Hulshof, David Medvigy, Camila Pizano, Christina M. Smith, Annette Trierweiler, Skip J. Van Bloem, Bonnie G. Waring, Xiangtao Xu, Jennifer S. Powers Feb 2017

Will Seasonally Dry Tropical Forests Be Sensitive Or Resistant To Future Changes In Rainfall Regimes?, Kara Allen, Juan Manuel Dupuy, Maria G. Gei, Catherine Hulshof, David Medvigy, Camila Pizano, Christina M. Smith, Annette Trierweiler, Skip J. Van Bloem, Bonnie G. Waring, Xiangtao Xu, Jennifer S. Powers

Publications

Seasonally dry tropical forests (SDTF) are located in regions with alternating wet and dry seasons, with dry seasons that last several months or more. By the end of the 21st century, climate models predict substantial changes in rainfall regimes across these regions, but little is known about how individuals, species, and communities in SDTF will cope with the hotter, drier conditions predicted by climate models. In this review, we explore different rainfall scenarios that may result in ecological drought in SDTF through the lens of two alternative hypotheses: 1) these forests will be sensitive to drought because they are already …


Exploring Historical Coffee And Climate Relations In Southern Guatemala: An Integration Of Tree Ring Analysis And Remote Sensing Data, Diego Pons Jan 2017

Exploring Historical Coffee And Climate Relations In Southern Guatemala: An Integration Of Tree Ring Analysis And Remote Sensing Data, Diego Pons

Electronic Theses and Dissertations

This dissertation makes use of a physical geography perspective to examine the relationship between agriculture and climate in Guatemala using dendrochronology. I examined the potential of high-resolution climate proxy data from dendrochronology to help fill in the gaps of past climate information to better understand the natural and anthropogenic variability of precipitation which, in turn, can inform Guatemala’s agriculture sector. This research has demonstrated successful cross-dating and climate sensitivity of Abies guatemalensis in the Pacific slope of Guatemala. Based on this, I have produced a 124-year record of mean precipitation from June-July-August. The mean precipitation from June-July-August at this site …


Information Technology Approaches To Forest Management, Mary Snow, Richard Snow Jan 2017

Information Technology Approaches To Forest Management, Mary Snow, Richard Snow

Publications

The majority of the world’s forests occur where there is a dry season long enough to affect a seasonal change in the forest community. The seasonal forest may include evergreen, semi-deciduous, deciduous trees, or some combination of these. Local differences in soil or other site characteristics often determine which community persists. Since the seasonal forests exist where there is seasonal precipitation, the character of the forest is closely associated with the length of the rainy season. As the length of the rainy season decreases, the density of the canopy decreases. If the global climate system warms and prolonged drought gives …


Effects Of In-Situ Leaf-Level Canopy Warming In A Northern Hardwood Forest, Kelsey Carter Jan 2017

Effects Of In-Situ Leaf-Level Canopy Warming In A Northern Hardwood Forest, Kelsey Carter

Dissertations, Master's Theses and Master's Reports

Rising mean annual temperatures due to climate change have intensified the need to understand the effects of warming on plant physiological processes. Forest photosynthesis is the most important pathways of terrestrial carbon sequestration, yet continued warming could reduce this important carbon sink. Photosynthesis is highly sensitive to temperature and begins to decline after an optimum temperature (Topt) is reached, leading to reduced carbon uptake. To date, logistical difficulties have limited our ability to test photosynthetic responses to sustained warming in mature forest canopies. In order to understand how elevated temperatures will affect forest ecosystems, we need to be …


Forest Ecosystems Of Temperate Climatic Regions: From Ancient Use To Climate Change, Frank S. Gilliam Dec 2016

Forest Ecosystems Of Temperate Climatic Regions: From Ancient Use To Climate Change, Frank S. Gilliam

Biological Sciences Faculty Research

Humans have long utilized resources from all forest biomes, but the most indelible anthropogenic signature has been the expanse of human populations in temperate forests. The purpose of this review is to bring into focus the diverse forests of the temperate region of the biosphere, including those of hardwood, conifer and mixed dominance, with a particular emphasis on crucial challenges for the future of these forested areas. Implicit in the term ‘temperate’ is that the predominant climate of these forest regions has distinct cyclic, seasonal changes involving periods of growth and dormancy. The specific temporal patterns of seasonal change, however, …


Agricultural Trade Publications And The 2012 Midwestern U.S. Drought: A Missed Opportunity For Climate Risk Communication, Sarah P. Church, Tonya Haigh, Melissa Widhalm, Silvestre Garcia De Jalon, Nicholas Babin, Stuart Carlton, Michael Dunn, Katie Fagan, Cody L. Knutson, Linda Stalker Prokopy Nov 2016

Agricultural Trade Publications And The 2012 Midwestern U.S. Drought: A Missed Opportunity For Climate Risk Communication, Sarah P. Church, Tonya Haigh, Melissa Widhalm, Silvestre Garcia De Jalon, Nicholas Babin, Stuart Carlton, Michael Dunn, Katie Fagan, Cody L. Knutson, Linda Stalker Prokopy

Department of Forestry & Natural Resources Faculty Publications

The Midwestern United States experienced a devastating drought in 2012, leading to reduced corn and soybean yields and increased instances of pests and disease. Climate change induced weather variability and extremes are expected to increase in the future, and have and will continue to impact the agricultural sector. This study investigated how agricultural trade publications portrayed the 2012 U.S. Midwestern drought, whether climate change was associated with drought, and whether these publications laid out transformative adaptation measures farmers could undertake in order to increase their adaptive capacity for future climate uncertainty. We performed a content analysis of 1000 media reports …


Useful To Usable: Developing Usable Climate Science For Agriculture, Linda S. Prokopy, J Stuart Carlton, Tonya Haigh, Maria Carmen Lemos, Amber Saylor Mase, Melissa Widhalm Oct 2016

Useful To Usable: Developing Usable Climate Science For Agriculture, Linda S. Prokopy, J Stuart Carlton, Tonya Haigh, Maria Carmen Lemos, Amber Saylor Mase, Melissa Widhalm

Department of Forestry & Natural Resources Faculty Publications

The Useful to Usable (U2U) project was a six-year research and extension project funded by the United States Department of Agriculture to provide both useful and usable climate information for the agricultural (corn) sector in the Midwestern United States. The project adopted an extensive co-production of knowledge and decision-making approach that involved intense iteration with potential end-users, including farmers and a variety of pro- fessional agricultural advisors, through focus groups and surveys, feedback at outreach events, and frequent informal interactions to develop both decision support tools and delivery mechanisms that met stakeholder needs. This overview paper for this special issue …


A Multiple‐Scale Assessment Of Long‐Term Aspen Persistence And Elevational Range Shifts In The Colorado Front Range, Mario Bretfeld, Scott B. Franklin, Robert K. Peet May 2016

A Multiple‐Scale Assessment Of Long‐Term Aspen Persistence And Elevational Range Shifts In The Colorado Front Range, Mario Bretfeld, Scott B. Franklin, Robert K. Peet

Aspen Bibliography

Aspen forests and woodlands are some of the most species‐rich forest communities in the northern hemisphere. Changing climate, altered disturbance regimes, land use, and increased herbivore pressure threaten these forests both in Eurasia and North America. In addition, rapid mortality dubbed “Sudden Aspen Decline” is a concern for aspen's long‐term presence in the western United States, especially Colorado and Utah. Yet it is still unclear whether aspen is persistent or declining at the landscape scale. We assessed aspen persistence at different spatial scales in the Colorado Front Range by resampling 89 plots containing aspen from among 305 vegetation plots sampled …


Riparian Trees And Aridland Streams Of The Southwestern United States: An Assessment Of The Past, Present, And Future, D. Max Smith, Deborah M. Finch Jan 2016

Riparian Trees And Aridland Streams Of The Southwestern United States: An Assessment Of The Past, Present, And Future, D. Max Smith, Deborah M. Finch

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Riparian ecosystems are vital components of aridlands within the southwestern United States. Historically, surface flows influenced population dynamics of native riparian trees. Many southwestern streams has been altered by regulation, however, and will be further affected by greenhouse warming. Our analysis of stream gage data revealed that decreases in volume of annual discharge and mean peak discharge and a shift to earlier peak discharge will occur in the Southern Rockies region of Colorado, New Mexico, and Utah. These changes will likely decrease rates of reproduction and survival of cottonwood (Populus fremontii and Populus deltoides ssp. wislizenii), Goodding's willow …


Short-Term Effects Of Warming Treatment And Precipitation Manipulation On The Ecophysiological Responses Of Pinus Densiflora Seedlings, Soon Jin Yun, Saerom Han, Seung Hyun Han, Seongjun Kim, Guanlin Li, Minji Park, Yowhan Son Jan 2016

Short-Term Effects Of Warming Treatment And Precipitation Manipulation On The Ecophysiological Responses Of Pinus Densiflora Seedlings, Soon Jin Yun, Saerom Han, Seung Hyun Han, Seongjun Kim, Guanlin Li, Minji Park, Yowhan Son

Turkish Journal of Agriculture and Forestry

The aim of this study was to investigate the short-term effects of warming treatment and precipitation manipulation on the growth, photosynthetic rate, and chlorophyll content of Pinus densiflora seedlings based on a climate change scenario in Korea. Two-year-old P. densiflora seedlings were planted in a nursery in April 2013. The air temperature of warmed plots (W) was set to increase by 3 °C compared to control plots (C) using an infrared heater in May 2013. The three precipitation manipulations consisted of decreased precipitation using transparent panels (-30%; P-), increased precipitation using pumps and drip irrigation (+30%; P+), and a control …


Short-Term Changes Of Leaf Area Index, Light Transmission, And Gap In A Temperate Mixed Deciduous Forest Ecosystem In Bartın, Turkey, İlyas Bolat, Ömer Kara, Meli̇h Öztürk Jan 2016

Short-Term Changes Of Leaf Area Index, Light Transmission, And Gap In A Temperate Mixed Deciduous Forest Ecosystem In Bartın, Turkey, İlyas Bolat, Ömer Kara, Meli̇h Öztürk

Turkish Journal of Agriculture and Forestry

In this study, leaf area index (LAI), light transmission, and gap were estimated by using the hemispherical photograph analysis technique with Hemisfer software version 1.5.3 for a temperate mixed deciduous forest. The height of the overall vegetation in the stand ranged from 15 to 20 m, and the diameters of the trees in the stand at breast height varied between 14 and 28 cm. This study showed that the mean value of LAI increased by 4% in the 5-year period from 2007 to 2012. LAI was significantly (P < 0.05) greater in 2012 than in 2007, whereas the mean percentage of light transmission was significantly lower in 2012 than it was in 2007. In addition, there was a significant (P < 0.01) correlation between LAI and light transmission, and there was also a statistically significant correlation between the gap and light transmission (P < 0.05). According to long-term meteorological data (1982-2012), this study also demonstrated that the mean air temperature rose approximately 1.0 °C between 2007 and 2012. Consequently, this study indicated that LAI varies with respect to time and the increase of LAI leads to a decrease in light transmission. Additionally, the air temperature and precipitation have a significant influence on the LAI.


Fire Severity Controlled Susceptibility To A 1940s Spruce Beetle Outbreak In Colorado, Usa, Dominik Kulakowski, Thomas T. Veblen, Peter Beb Jan 2016

Fire Severity Controlled Susceptibility To A 1940s Spruce Beetle Outbreak In Colorado, Usa, Dominik Kulakowski, Thomas T. Veblen, Peter Beb

Geography

The frequency, magnitude, and size of forest disturbances are increasing globally. Much recent research has focused on how the occurrence of one disturbance may affect susceptibility to subsequent disturbances. While much has been learned about such linked disturbances, the strength of the interactions is likely to be contingent on the severity of disturbances as well as climatic conditions, both of which can affect disturbance intensity and tree resistance to disturbances. Subalpine forests in western Colorado were affected by extensive and severe wildfires in the late 19th century and an extensive and severe outbreak of spruce beetle (Dendroctonus rufipennis) in the …


Not Only Climate: Interacting Drivers Of Treeline Change In Europe, Dominik Kulakowski, Ignacio Barbeito, Alejandro Casteller, Ryszard J. Kaczka, Peter Bebi Jan 2016

Not Only Climate: Interacting Drivers Of Treeline Change In Europe, Dominik Kulakowski, Ignacio Barbeito, Alejandro Casteller, Ryszard J. Kaczka, Peter Bebi

Geography

Treelines have long been recognized as important ecotones and likely harbingers of climate change. However, over the last century many treelines have been affected not only by global warming, but also by the interactions of climate, forest disturbance and the consequences of abrupt demographic and economic changes. Recent research has increasingly stressed how multiple ecological, biophysical, and human factors interact to shape ecological dynamics. Here we highlight the need to consider interactions among multiple drivers to more completely understand and predict treeline dynamics in Europe.


A Forest Vulnerability Index Based On Drought And High Temperatures, David Mildrexler, Zhiqiang Yang, Warren B. Cohen, David M. Bell Jan 2016

A Forest Vulnerability Index Based On Drought And High Temperatures, David Mildrexler, Zhiqiang Yang, Warren B. Cohen, David M. Bell

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Increasing forest stress and tree mortality has been directly linked to combinations of drought and high temperatures. The climatic changes expected during the next decades – large increases in mean temperature, increased heat waves, and significant long-term regional drying in the western USA – will likely increase chronic forest stress and mortality. The aim of this research is to develop and apply a new forest vulnerability index (FVI) associated with drought and high temperatures across the Pacific Northwest region (PNW; Oregon and Washington) of the USA during the MODIS Aqua era (since 2003). Our technique incorporates the alterations to canopy …


Contributing Factors For Drought In United States Forest Ecosystems Under Projected Future Climates And Their Uncertainty, Charles H. Luce, James M. Vose, Neil Pederson, John Campbell, Connie Millar, Patrick Kormos, Ross Woods Jan 2016

Contributing Factors For Drought In United States Forest Ecosystems Under Projected Future Climates And Their Uncertainty, Charles H. Luce, James M. Vose, Neil Pederson, John Campbell, Connie Millar, Patrick Kormos, Ross Woods

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Observations of increasing global forest die-off related to drought are leading to more questions about potential increases in drought occurrence, severity, and ecological consequence in the future. Dry soils and warm temperatures interact to affect trees during drought; so understanding shifting risks requires some understanding of changes in both temperature and precipitation. Unfortunately, strong precipitation uncertainties in climate models yield substantial uncertainty in projections of drought occurrence. We argue that disambiguation of drought effects into temperature and precipitation-mediated processes can alleviate some of the implied uncertainty. In particular, the disambiguation can clarify geographic diversity in forest sensitivity to multifarious drivers …


Climate-Suitable Planting As A Strategy For Maintaining Forest Productivity And Functional Diversity, Matthew Joshua Duveneck, Robert M. Scheller Sep 2015

Climate-Suitable Planting As A Strategy For Maintaining Forest Productivity And Functional Diversity, Matthew Joshua Duveneck, Robert M. Scheller

Environmental Science and Management Faculty Publications and Presentations

Within the time frame of the longevity of tree species, climate change will change faster than the ability of natural tree migration. Migration lags may result in reduced productivity and reduced diversity in forests under current management and climate change. We evaluated the efficacy of planting climate-suitable tree species (CSP), those tree species with current or historic distributions immediately south of a focal landscape, to maintain or increase aboveground biomass, productivity, and species and functional diversity. We modeled forest change with the LANDIS-II forest simulation model for 100 years (2000–2100) at a 2-ha cell resolution and five-year time steps within …


Economic Impact Of Net Carbon Payments And Bioenergy Production In Fertilized And Non-Fertilized Loblolly Pine Plantations, Prativa Shrestha, George A. Stainback, Puneet Dwivedi Sep 2015

Economic Impact Of Net Carbon Payments And Bioenergy Production In Fertilized And Non-Fertilized Loblolly Pine Plantations, Prativa Shrestha, George A. Stainback, Puneet Dwivedi

Forestry and Natural Resources Faculty Publications

Sequestering carbon in forest stands and using woody bioenergy are two potential ways to utilize forests in mitigating emissions of greenhouse gases (GHGs). Such forestry related strategies are, however, greatly influenced by carbon and bioenergy markets. This study investigates the impact of both carbon and woody bioenergy markets on land expectation value (LEV) and rotation age of loblolly pine (Pinus taeda L.) forests in the southeastern United States for two scenarios—one with thinning and no fertilization and the other with thinning and fertilization. Economic analysis was conducted using a modified Hartman model. The amount of carbon dioxide (CO2 …


Agenda: Seeds Of Change: Responding To Global Change In A Bottom-Up World, University Of Colorado Boulder. Getches-Wilkinson Center For Natural Resources, Energy, And The Environment, University Of Colorado Boulder. School Of Law, Posner Center For International Development, Resolve (Firm), Newmont Mining Corporation Feb 2015

Agenda: Seeds Of Change: Responding To Global Change In A Bottom-Up World, University Of Colorado Boulder. Getches-Wilkinson Center For Natural Resources, Energy, And The Environment, University Of Colorado Boulder. School Of Law, Posner Center For International Development, Resolve (Firm), Newmont Mining Corporation

Seeds of Change: Responding to Global Change in a Bottom-Up World (Martz Winter Symposium, February 12-13)

Sponsors: Posner Center for International Development, RESOLVE, Inc., Newmont Mining Corporation, and Getches-Wilkinson Center for Natural Resources, Energy, and the Environment.

Conference moderators, panelists and speakers included University of Colorado Law School professors Phil Weiser, Sarah Krakoff, Britt Banks, and Lakshman Guruswamy.

This conference is made possible through the generous support of donors who sponsored this year’s Martz Sustainability Symposium (including Newmont Mining Corporation) and those who have invested in our Clyde O. Martz Endowed Fund for Natural Resources Management (including Brian Dolan and Davis Graham and Stubbs LLP). The Martz Natural Resources Management Fund was established in the memory …


Effects Of Drought On Forests And Rangelands In The United States: A Comprehensive Science Synthesis, James M. Vose, James S. Clark, Charles H. Luce, Toral Patel-Weynand Jan 2015

Effects Of Drought On Forests And Rangelands In The United States: A Comprehensive Science Synthesis, James M. Vose, James S. Clark, Charles H. Luce, Toral Patel-Weynand

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

This assessment provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA), and it establishes the scientific foundation needed to manage for drought resilience and adaptation. Focal areas include drought characterization; drought impacts on forest processes and disturbances such as insect outbreaks and wildfire; and consequences on forest and rangeland values. Drought can be a severe natural disaster with substantial social and economic consequences. Drought becomes most obvious when large-scale changes are observed; however, even moderate drought can have long-lasting impacts on the structure and function of forests and rangelands without these obvious …


Interactions Among Spruce Beetle Disturbance, Climate Change And Forest Dynamics Captured By A Forest Landscape Model, Christian Temperli, Thomas T. Veblen, Sarah J. Hart, Dominik Kulakowski, Alan J. Tepley Jan 2015

Interactions Among Spruce Beetle Disturbance, Climate Change And Forest Dynamics Captured By A Forest Landscape Model, Christian Temperli, Thomas T. Veblen, Sarah J. Hart, Dominik Kulakowski, Alan J. Tepley

Geography

The risk of bark beetle outbreaks is widely predicted to increase because of a warming climate that accelerates temperature-driven beetle population growth and drought stress that impairs host tree defenses. However, few if any studies have explicitly evaluated climatically enhanced beetle population dynamics in relation to climate-driven changes in forest composition and structure that may alter forest suitability for beetle infestation. We synthesized current understanding of the interactions among climate, spruce beetles (Dendroctonus rufipennis) and forest dynamics to parameterize and further advance the bark beetle module of a dynamic forest landscape model (LandClim) that also integrates fire and wind disturbance …


Instantaneous Photosynthetic Response To Temperature Of Mature Forest Canopies And Experimentally Warmed Seedlings, Alida C. Mau Jan 2015

Instantaneous Photosynthetic Response To Temperature Of Mature Forest Canopies And Experimentally Warmed Seedlings, Alida C. Mau

Dissertations, Master's Theses and Master's Reports - Open

Tropical trees have been shown to be more susceptible to warming compared to temperate species, and have shown growth and photosynthetic declines at elevated temperatures as little as 3oC above ambient. However, regional and global vegetation models lack the data needed to accurately represent physiological response to increased temperatures in tropical forests. We compared the instantaneous photosynthetic responses to elevated temperatures of four mature tropical rainforest tree species in Puerto Rico and the temperate broadleaf species sugar maple (Acer saccharum) in Michigan. Contrary to expectations, leaves in the upper canopy of both temperate and tropical forests had temperature …


Negative Feedbacks On Bark Beetle Outbreaks: Widespread And Severe Spruce Beetle Infestation Restricts Subsequent Infestation, Sarah J. Hart, Thomas T. Veblen, Nathan Mietkiewicz, Dominik Kulakowski Jan 2015

Negative Feedbacks On Bark Beetle Outbreaks: Widespread And Severe Spruce Beetle Infestation Restricts Subsequent Infestation, Sarah J. Hart, Thomas T. Veblen, Nathan Mietkiewicz, Dominik Kulakowski

Geography

Understanding disturbance interactions and their ecological consequences remains a major challenge for research on the response of forests to a changing climate. When, where, and how one disturbance may alter the severity, extent, or occurrence probability of a subsequent disturbance is encapsulated by the concept of linked disturbances. Here, we evaluated 1) how climate and forest habitat variables, including disturbance history, interact to drive 2000s spruce beetle (Dendroctonus rufipennis) infestation of Engelmann spruce (Picea engelmannii) across the Southern Rocky Mountains; and 2) how previous spruce beetle infestation affects subsequent infestation across the Flat Tops Wilderness in northwestern Colorado, which experienced …


On Underestimation Of Global Vulnerability To Tree Mortality And Forest Die-Off From Hotter Drought In The Anthropocene, Craig D. Allen, David D. Breshears, Nate G. Mcdowell Jan 2015

On Underestimation Of Global Vulnerability To Tree Mortality And Forest Die-Off From Hotter Drought In The Anthropocene, Craig D. Allen, David D. Breshears, Nate G. Mcdowell

United States Geological Survey: Staff Publications

Patterns, mechanisms, projections, and consequences of tree mortality and associated broadscale forest die-off due to drought accompanied by warmer temperatures—‘‘hotter drought’’, an emerging characteristic of the Anthropocene—are the focus of rapidly expanding literature. Despite recent observational, experimental, and modeling studies suggesting increased vulnerability of trees to hotter drought and associated pests and pathogens, substantial debate remains among research, management and policy-making communities regarding future tree mortality risks. We summarize key mortalityrelevant findings, differentiating between those implying lesser versus greater levels of vulnerability. Evidence suggesting lesser vulnerability includes forest benefits of elevated [CO2] and increased water-use efficiency; observed and modeled increases …