Nathan L Stephenson

Mortality factors for dead trees from a subset of plots from the Sierra Nevada Forest Dynamics Plot Network from 1998 to 2010

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

Categories: Data; Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Sequoia-Kings Canyon National Park, Sierra Nevada, USGS Science Data Catalog (SDC), Yosemite National Park, bark beetles, All tags... tree mortality, tree mortality factors, tree pathogens, Fewer tags

Sequoia and Yosemite National Parks Mortality and Fire Data (1990-2019) for Competition-Fire-Drought Interaction Analysis

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

Categories: Data; Tags: California, Forestry, Sequoia National Park, Sierra Nevada, USGS Science Data Catalog (SDC), All tags... Yosemite National Park, bark beetle, biota, fires, forest ecosystems, insects, plot sampling, temperate forest, tree mortality, Fewer tags

Effects of Postfire Climate and Seed Availability on Postfire Conifer Regeneration

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

Mapping the vulnerability of giant sequoias after extreme drought in California using remote sensing

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

Seed Source, Not Drought, Determines Patterns of Seed Production in Sierra Nevada Conifers (ver. 2.0, January 2023)

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.

Categories: Data; Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: California, Holocene, Sequoia-Kings National Park, Terrestrial surface, USGS Science Data Catalog (SDC), All tags... Yosemite National Park, biota, coniferous trees, current, drought and seed production, forest ecosystems, long-term ecological monitoring, spring (season), summer, time series datasets, Fewer tags