-
Medieval warming initiated exceptionally large wildfire outbreaks in the Rocky Mountains
-
Many of the largest wildfires in US history burned in recent decades, and climate change explains much of the increase in area burned. The frequency of extreme wildfire weather will increase with continued warming, but many uncertainties still exist about future fire regimes, including how the risk of large fires will persist as vegetation changes. Past fire-climate relationships provide an opportunity to constrain the related uncertainties, and reveal widespread burn- ing across large regions of western North America during past warm intervals. Whether such episodes also burned large portions of individual landscapes has been difficult to determine, however, because uncertainties with the ages of past fires and limited spatial resolution often prohibit specific estimates of past area burned. Accounting for these challenges in a subalpine landscape in Colorado, we estimated century-scale fire synchroneity across 12 lake- sediment charcoal records spanning the past 2,000 y. The percent- age of sites burned only deviated from the historic range of vari- ability during the Medieval Climate Anomaly (MCA) between 1,200 and 850 y B.P., when temperatures were similar to recent decades. Between 1,130 and 1,030 y B.P., 83% (median estimate) of our sites burned when temperatures increased ∼0.5 °C relative to the preceding centuries. Lake-based fire rotation during the MCA decreased to an estimated 120 y, representing a 260% higher rate of burning than during the period of dendroecological sampling (360 to −60 y B.P.). Increased burning, however, did not persist throughout the MCA. Burning declined abruptly before temperatures cooled, indicating possible fuel limitations to continued burning.
Located in
Resources
/
Climate Science Documents
-
Michigan State University Extension: Great Lakes Leadership Academy
-
The mission of the Great Lakes Leadership Academy is to promote positive change, economic vitality, and resource conservation and enhance the quality of life in Michigan by encouraging leadership for the common good.
Located in
Training
/
Training programs
-
National Report on Sustainable Forests
-
This is a report on the state of forests in the United States of America and the indicators of national progress toward the goal of sustainable forest management. The report is designed to provide information that will improve public dialog and decision making on desired outcomes and needed actions to move the Nation toward this goal. The 64 indicators of forest sustainability used in the report reflect many of the environmental, social, and economic concerns of the American public regarding forests, and they help us establish a quantitative baseline for measuring progress toward sustainability. While the report presents data primarily at a national or regional level, it also provides a valuable context for related efforts to ensure sustainability at other geographic and political scales. Action at all levels is vital to achieving sustainable forest management in the United States.
The current edition includes 130 pages of detailed information organized by indicator, as well as summary analyses and policy recommendations. Over 30 Forest Service scientists, senior staff and outside collaborators contributed to this edition of the report. A previous edition of the report was released in 2003, and an update is anticipated for 2015. Questions or comments about the report or the project as a whole are greatly appreciated and can be directed to Guy Robertson (see box on left).
Located in
Resources
/
General Resources Holdings
/
Science Publications
-
NCASI
-
The National Council for Air and Stream Improvement, Inc. (NCASI) is a 501 (c)(6) tax-exempt association organized to serve the forest products industry as a center of excellence providing unbiased, scientific research and technical information necessary to achieve the industry’s environmental and sustainability goals.
Our Mission
NCASI’s mission is to help our members cost-effectively meet their environmental and sustainability goals through basic and applied research, technical support, and education.
Through execution of our Mission, we provide essential support to our forest products industry members in their efforts to ensure the availability of a sustainably managed fiber supply, characterize and help improve the effectiveness of pollution control measures at manufacturing facilities and provide valuable insights and assistance to members in the manufacture of sustainable forest products.
Located in
LP Members
/
Organizations Search
-
Novel climates, no-analog communities, and ecological surprises
-
No-analog communities (communities that are compositionally unlike any found today) occurred frequently in the past and will develop in the greenhouse world of the future. The well documented no-analog plant communities of late-glacial North America are closely linked to “novel” climates also lacking modern analogs, characterized by high seasonality of temperature. In climate simulations for the Intergovernmental Panel on Climate Change A2 and B1 emission scenarios, novel climates arise by 2100 AD, primarily in tropical and subtropical regions. These future novel climates are warmer than any present climates globally, with spatially variable shifts in precipitation, and increase the risk of species reshuffling into future no-analog communities and other ecological surprises. Most ecological models are at least partially parameterized from modern observations and so may fail to accurately predict ecological responses to these novel climates. There is an urgent need to test the robustness of ecological models to climate conditions outside modern experience.
Located in
Resources
/
Climate Science Documents
-
Observations of Climate Change in the AppLCC
-
Observations and likely outcomes from changing climate for AppLCC natural resources.
Located in
Resources
/
General Resources Holdings
/
AppLCC Development and Operations Planning
-
On the difference in the net ecosystem exchange of CO2 between deciduous and evergreen forests in the southeastern United States
-
The southeastern United States is experiencing a rapid regional increase in the ratio of pine to deciduous forest ecosystems at the same time it is experiencing changes in climate. This study is focused on exploring how these shifts will affect the carbon sink capacity of southeastern US forests, which we show here are among the strongest carbon sinks in the continental United States. Using eight-year-long eddy covariance records collected above a hardwood deciduous forest (HW) and a pine plantation (PP) co-located in North Carolina, USA, we show that the net ecosystem exchange of CO2 (NEE) was more variable in PP, contributing to variability in the difference in NEE between the two sites (DNEE) at a range of timescales, including the interannual timescale. Because the variability in evapotranspira- tion (ET) was nearly identical across the two sites over a range of timescales, the factors that determined the variabil- ity in DNEE were dominated by those that tend to decouple NEE from ET. One such factor was water use efficiency, which changed dramatically in response to drought and also tended to increase monotonically in nondrought years (P < 0.001 in PP). Factors that vary over seasonal timescales were strong determinants of the NEE in the HW site; however, seasonality was less important in the PP site, where significant amounts of carbon were assimilated outside of the active season, representing an important advantage of evergreen trees in warm, temperate climates. Additional variability in the fluxes at long-time scales may be attributable to slowly evolving factors, including canopy structure and increases in dormant season air temperature. Taken together, study results suggest that the carbon sink in the southeastern United States may become more variable in the future, owing to a predicted increase in drought frequency and an increase in the fractional cover of southern pines.
Located in
Resources
/
Climate Science Documents
-
Palaeodata-informed modelling of large carbon losses from recent burning of boreal forests
-
Wildfires play a key role in the boreal forest carbon cycle(1,2), and models suggest that accelerated burning will increase boreal C emissions in the coming century (3). However, these predictions may be compromised because brief observational records provide limited constraints to model initial conditions (4). We confronted this limitation by using palaeoenvironmental data to drive simulations of long-term C dynamics in the Alaskan bo- real forest. Results show that fire was the dominant control on C cycling over the past millennium, with changes in fire frequency accounting for 84% of C stock variability. A recent rise in fire frequency inferred from the palaeorecord5 led to simulated C losses of 1.4 kg C m?2(12% of ecosystem C stocks) from 1950 to 2006. In stark contrast, a small net C sink of 0.3 kg C m?2 occurred if the past fire regime was assumed to be similar to the modern regime, as is common in models of C dynamics. Although boreal fire regimes are heterogeneous, recent trends6 and future projections (7) point to increasing fire activity in response to climate warming throughout the biome. Thus, predictions (8) that terrestrial C sinks of northern high latitudes will mitigate rising atmospheric CO2 may be over-optimistic.
Located in
Resources
/
Climate Science Documents
-
Re:wild
-
Re:wild's mission is to protect and restore the wild to build a thriving Earth where all life flourishes.
Located in
LP Members
/
Organizations Search
-
Seeing the landscape for the trees: Metrics to guide riparian shade management in river catchments
-
Rising water temperature (Tw) due to anthropogenic climate change may have serious conse- quences for river ecosystems. Conservation and/or expansion of riparian shade could counter warming and buy time for ecosystems to adapt. However, sensitivity of river reaches to direct solar radiation is highly het- erogeneous in space and time, so benefits of shading are also expected to be site specific. We use a network of high-resolution temperature measurements from two upland rivers in the UK, in conjunction with topo- graphic shade modeling, to assess the relative significance of landscape and riparian shade to the thermal behavior of river reaches. Trees occupy 7% of the study catchments (comparable with the UK national aver- age) yet shade covers 52% of the area and is concentrated along river corridors. Riparian shade is most ben- eficial for managing Tw at distances 5–20 km downstream from the source of the rivers where discharge is modest, flow is dominated by near-surface hydrological pathways, there is a wide floodplain with little land- scape shade, and where cumulative solar exposure times are sufficient to affect Tw. For the rivers studied, we find that approximately 0.5 km of complete shade is necessary to off-set Tw by 18C during July (the month with peak Tw) at a headwater site; whereas 1.1 km of shade is required 25 km downstream. Further research is needed to assess the integrated effect of future changes in air temperature, sunshine duration, direct solar radiation, and downward diffuse radiation on Tw to help tree planting schemes achieve
Located in
Resources
/
Climate Science Documents
