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This dataset was used to summarize and analyze the mortality factors recorderd on dead trees in the Sierra Nevada Forest Dynamics Plot Network, which is managed by the Sequoia and Kings Canyon Field station of the U.S. Geological Survey's Western Ecological Research Center. Each row of the dataset represents an individual dead tree. These are dead trees that were recorded in the network from 1998 to 2010 for the subset of plots as described in the associated manuscript; These data support the following: Das, A.J., Stephenson, N.L., Davis, K.P. 2016. Why do trees die? Characterizing the drivers of background tree mortality. Ecology. 97(10): 2616-2627, https://doi.org/10.1002/ecy.1497
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This dataset records mortality-- including involvement of bark beetles-- and burn severity information for trees in long term forest dynamics plots in Sequoia National Park and Yosemite National Park that experienced fire. These data support the following publication: Furniss, T.J., Das, A.J., van Mantgem, P.J., Stephenson, N.L. and Lutz, J.A., 2021. Crowding, climate, and the case for social distancing among trees. Ecological Applications, p.e2507, https://doi.org/10.1002/eap.2507
Abstract (from Ecological Society of America): Large, severe fires are becoming more frequent in many forest types across the western United States and have resulted in tree mortality across tens of thousands of hectares. Conifer regeneration in these areas is limited because seeds must travel long distances to reach the interior of large burned patches and establishment is jeopardized by increasingly hot and dry conditions. To better inform postfire management in low elevation forests of California, USA, we collected 5‐year postfire recovery data from 1,234 study plots in 19 wildfires that burned from 2004–2012 and 18 years of seed production data from 216 seed fall traps (1999–2017). We used this data in conjunction...
Categories: Publication; Types: Citation
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This release consists of data collected from 26 plots in two national parks over a 19-year period. The data consists of plot-level seed counts for three genera, number of seed traps, live tree basal area, plot area, and climate metrics from the gridmet gridded data set, the daymet gridded data set, the PRISM gridded data set, and two nearby COOP stations.
Between 2012 and 2016, California suffered one of the most severe droughts on record. During this period Sequoiadendron giganteum (giant sequoias) in the Sequoia and Kings Canyon National Parks (SEKI), California, USA experienced canopy water content (CWC) loss, unprecedented foliage senescence, and, in a few cases, death. We present an assessment of the vulnerability of giant sequoia populations to droughts that is currently lacking and needed for management. We used a temporal trend of remotely sensed CWC obtained between 2015 and 2017, and recently georeferenced giant sequoia crowns to quantify the vulnerability of 7,408 individuals in 10 groves in the northern portion of SEKI. CWC is sensitive to changes in...
Categories: Publication; Types: Citation
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These data were collected to quantify oak mortality during the 2014-2017 drought. 30 tenth hectare drought plots were established throughout the blue oak woodland of Sequoia National Park. Information on species, size, and mortality were collected for all standing trees in each plot. In addition, two long-term 2.25 ha plots were established, in which the same data were collected. These data are associated with the following publication: Das, A.J., Ampersee, N.J., Pfaff, A.H., Stephenson, N.L., Swiecki, T.J., Bernhardt, E.A., Haggerty, P.K. and Nydick, K.R., 2020. Tree mortality in blue oak woodland during extreme drought in Sequoia National Park, California. Madroño, 66(4), pp.164-175.
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These data describe tree mortality and the factors associated with tree mortality for a variety of plots in Sequoia National Park. Most of the data were collected between 2014 and 2017 (during an extremely severe drought), along with some comparison data from 2004 to 2007. These data support the following publication: Stephenson, N.L., Das, A.J., Ampersee, N.J., Bulaon, B.M., and Yee, J.L., In review. Which trees die during drought? The key role of insect host-tree selection, Journal of Ecology
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Natural & cultural resource managers are facing a slew of new challenges for managing public lands stemming from climate change and human-driven stressors like invasive species, fragmentation, and new resource uses. In some cases, the very landscapes and species they are managing are changing in significant ways, transforming from one set of conditions to another. As a result, previously successful management strategies may become less effective, or in some cases ineffective. New and transforming conditions leave managers in a bind on how to respond to transforming public lands and natural resources. On the most basic level managers have three choices of how to respond: resist change, accept change, or direct change...
This table provides, for each of the 403 species used in our analysis, various documentary information as well as the fitted parameters for the relationship between mass growth rate and the natural log of tree size. The independent variable ln(mass) was divided into bins and a separate line segment was fitted to mass growth rate versus ln(mass) in each bin so that the line segments met at the bin divisions. Mass and growth rate were in megagrams (Mg) and Mg yr-1 respectively. Bin divisions were not assigned a priori but were fitted by the model separately for each species. We fitted models with 1, 2, 3, and 4 bins, and selected the model receiving the most support by Akaike’s Information Criterion for each species....
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These datasets provide spatially-explicit estimates of the magnitude of giant sequoia foliage dieback along selected trail corridors in Sequoia and Kings Canyon national parks, California, from 2014 through 2017. They additionally provide giant sequoia tree-ring measurements, through the year 1989, for two locations in the Giant Forest grove, Sequoia National Park, California. These data support the following publications: Nathan L. Stephenson, Adrian J. Das, Nicholas J. Ampersee, Kathleen G. Cahill, Anthony C. Caprio, John E. Sanders, A. Park Williams, Patterns and correlates of giant sequoia foliage dieback during California’s 2012–2016 hotter drought, Forest Ecology and Management, Available online 7 November...
Postfire Spatial Conifer Restoration Planning Tool (POSCRPT) R package (and web version) predicts the probability of post-fire conifer regeneration for fire data supplied by the user. The predictive model was fit using presence/absence data collected five years after wildfire, from 1,234 4.4m radius plots (60m2), spanning 19 wildfires in California. Please refer to Stewart et al. (2020) for more details. The poscrptR tool is designed to simplify the process of predicting post-fire conifer regeneration under different precipitation and seed production scenarios. The app was designed to use Rapid Assessment of Vegetative Condition (RAVG) data inputs. The RAVG website has both RdNBR and fire perimeter data sets...
Large, severe fires are becoming more frequent in many forest types across the western United States and have resulted in tree mortality across tens of thousands of hectares. Conifer regeneration in these areas is limited because seeds must travel long distances to reach the interior of large burned patches and establishment is jeopardized by increasingly hot and dry conditions. To better inform postfire management in low elevation forests of California, USA, we collected 5‐yr postfire recovery data from 1,234 study plots in 19 wildfires that burned from 2004–2012 and 18 yrs of seed production data from 216 seed fall traps (1999–2017). We used these data in conjunction with spatially extensive climate, topography,...
Categories: Publication; Types: Citation
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Drought is one of the biggest threats facing our forests today. In the western U.S., severe drought and rising temperatures have caused increased tree mortality and complete forest diebacks. Forests are changing rapidly, and while land managers are working to develop long-term climate change adaptation plans, they require tools that can enhance forest resistance to drought now. To address this immediate need, researchers are examining whether a common forest management tool, prescribed fire, can be implemented to help forests better survive drought. Prescribed fire is commonly used in the western U.S. to remove potential wildfire fuel, such as small trees and shrubs. It is also thought that this act of selectively...
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Forests sequester the majority of the terrestrial biosphere’s carbon and are key components of the global carbon cycle, potentially contributing substantial feedbacks to ongoing climatic changes. It is therefore remarkable that no consensus yet exists about the fundamental nature of tree mass growth (and thus carbon sequestration rate). Specifically, does tree mass growth rate increase, decrease, or stay the same with increasing tree size? The answer could have profound implications for our ability to forecast the role of forests in the global carbon cycle and to devise appropriate adaptation and mitigation strategies for forests in the face of rapid climatic changes. We will conduct the first global-scale characterization...
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These data support poscrptR (Wright et al. 2021). poscrptR is a shiny app that predicts the probability of post-fire conifer regeneration for fire data supplied by the user. The predictive model was fit using presence/absence data collected in 4.4m radius plots (60 square meters). Please refer to Stewart et al. (2020) for more details concerning field data collection, the model fitting process, and limitations. Learn more about shiny apps at https://shiny.rstudio.com. The app is designed to simplify the process of predicting post-fire conifer regeneration under different precipitation and seed production scenarios. The app requires the user to upload two input data sets: 1. a raster of Relativized differenced Normalized...
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These data represent tree diameter, species, mortality status, and plot attributes from 164 plots in Sequoia and Kings Canyon national parks, California. Plots were matched with local records of recent fire history to determine burn status and year burned if applicable. These data support the following publication: van Mantgem, P.J., Caprio, A.C., Stephenson, N.L. and Das, A.J., 2021. Forest Resistance to Extended Drought Enhanced by Prescribed Fire in Low Elevation Forests of the Sierra Nevada. Forests, 12(9), p.1248.
Prescribed fire reduces fire hazards by removing dead and live fuels (small trees and shrubs). Reductions in forest density following prescribed fire treatments (often in concert with mechanical treatments) may also lessen competition so that residual trees might be more likely to survive when confronted with additional stressors, such as drought. The current evidence for these effects is mixed and additional study is needed. Previous work found increased tree survivorship in low elevation forests with a recent history of fire during the early years of an intense drought (2012 to 2014) in national parks in the southern Sierra Nevada. We extend these observations through additional years of intense drought and continuing...
Categories: Publication; Types: Citation
This dataset was used as part of a continent-wide analysis of tree fecundity and its association with climate and tree size. This dataset consists of: plotinfo.csv, which contains basic attribute information for the field plots where the data were collected; seeddata.csv, which contains the data for seeds collected (how many, what type, etc.); trapxycoord.csv, which contains location and identification information for the seed traps used to collect the seeds; treexycoord.csv, which contains location and attribute information for the standing trees in the plot where the seeds were collected; and treedata.csv, which contains data on the size and species of standing trees in the plot where the seeds were collected.
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The Southwest U.S. is experiencing hotter droughts, which are contributing to more frequent, severe wildfires. These droughts also stress vegetation, which can make it more difficult for forests to recover after fire. Forest regeneration in burned areas may be limited because seeds have to travel long distances to recolonize, and when they do arrive, conditions are often unfavorably hot and dry. Conifer forests in the region have demonstrated particular difficulty in recovering after fires, and in some cases have transformed into other ecosystem types, such as deciduous-dominated forests or grasslands. Such ecological transformations have implications not only for the plants and animals that depend on conifer forests...
Reproduction is a key component of ecological resilience in forest ecosystems, so understanding how seed production is influenced by extreme drought is key to understanding forest recovery trajectories. If trees respond to mortality-inducing drought by preferentially allocating resources for reproduction, the recovery of the stand to pre-drought conditions may be enhanced accordingly. We used a 20-year annual seed capture data set to investigate whether seed production by three tree genera commonly found in the Sierra Nevada (Abies, Pinus, and Calocedrus) was correlated with variation in local weather, which included an extreme drought spanning multiple years. We tested whether average seed production differed during...
Categories: Publication; Types: Citation


map background search result map search result map Fighting Drought with Fire: A Comparison of Burned and Unburned Forests in Drought-Impacted Areas of the Southwest Mortality factors for dead trees from a subset of plots from the Sierra Nevada Forest Dynamics Plot Network from 1998 to 2010 Sequoia foliage dieback and tree-ring data from Sequoia National Park Post-Fire Conifer Regeneration Under a Warming Climate: Will Severe Fire Be a Catalyst for Forest Loss? Tree mortality in Sequoia National Park from 2004 to 2007 and during severe drought in 2014 to 2017 Tree mortality in blue oak woodlands in Sequoia National Park during extreme drought Seed Source, Not Drought, Determines Patterns of Seed Production in Sierra Nevada Conifers (ver. 2.0, January 2023) Data for Use in poscrptR Post-fire Conifer Regeneration Prediction Model Seed and Associated Tree Data from Long Term Research Plots in Sequoia and Yosemite National Parks Sequoia and Yosemite National Parks Mortality and Fire Data (1990-2019) for Competition-Fire-Drought Interaction Analysis Forest Structure Data for Burned and Unburned Sites at Sequoia and Kings Canyon National Parks Cross-Park RAD Project (CPRP): A Case Study in Four National Parks Investigating How Institutional Context and Emotions Shape Manager Decisions to Resist, Accept, or Direct Change in Transforming Ecosystems Tree mortality in blue oak woodlands in Sequoia National Park during extreme drought Tree mortality in Sequoia National Park from 2004 to 2007 and during severe drought in 2014 to 2017 Forest Structure Data for Burned and Unburned Sites at Sequoia and Kings Canyon National Parks Sequoia foliage dieback and tree-ring data from Sequoia National Park Seed Source, Not Drought, Determines Patterns of Seed Production in Sierra Nevada Conifers (ver. 2.0, January 2023) Seed and Associated Tree Data from Long Term Research Plots in Sequoia and Yosemite National Parks Sequoia and Yosemite National Parks Mortality and Fire Data (1990-2019) for Competition-Fire-Drought Interaction Analysis Mortality factors for dead trees from a subset of plots from the Sierra Nevada Forest Dynamics Plot Network from 1998 to 2010 Post-Fire Conifer Regeneration Under a Warming Climate: Will Severe Fire Be a Catalyst for Forest Loss? Data for Use in poscrptR Post-fire Conifer Regeneration Prediction Model Fighting Drought with Fire: A Comparison of Burned and Unburned Forests in Drought-Impacted Areas of the Southwest Cross-Park RAD Project (CPRP): A Case Study in Four National Parks Investigating How Institutional Context and Emotions Shape Manager Decisions to Resist, Accept, or Direct Change in Transforming Ecosystems