DOI: 10.5061/dryad.1rn8pk0sn
title: Data from: Effects of Bark Beetle Outbreaks on Forest Landscape Pattern in the Southern Rocky Mountains, U.S.A.

description: Since the late 1990s, extensive outbreaks of native bark beetles
 (Curculionidae: Scolytinae) have affected coniferous forests throughout
 Europe and North America, driving changes in carbon storage, wildlife
 habitat, nutrient cycling, and water resource provisioning. Remote sensing
 is a crucial tool for quantifying the effects of these disturbances across
 broad landscapes. In particular, Landsat time series (LTS) are
 increasingly used to characterize outbreak dynamics, including the
 presence and severity of bark beetle-caused tree mortality, though
 broad-scale LTS-based maps are rarely informed by detailed field
 validation. Here we used spatial and temporal information from LTS
 products, in combination with extensive field data and Random Forest (RF)
 models, to develop 30-m maps of the presence (i.e., any occurrence) and
 severity (i.e., cumulative percent basal area mortality) of beetle-caused
 tree mortality 1997-2019 in subalpine forests throughout the Southern
 Rocky Mountains, USA. Using resultant maps, we also quantified spatial
 patterns of cumulative tree mortality throughout the region, an important
 yet poorly understood concept in beetle-affected forests. RF models using
 LTS products to predict presence and severity performed well, with 80.3%
 correctly classified (Kappa = 0.61) and R2 = 0.68 (RMSE = 17.3),
 respectively. We found that ≥ 10,256 km2 of subalpine forest area (39.5%
 of the study area) was affected by bark beetles and 19.3% of the study
 area experienced ≥ 70% tree mortality over the twenty-three year period.
 Variograms indicated that severity was autocorrelated at scales &lt;
 250 km. Interestingly, cumulative patch-size distributions showed that
 areas with a near-total loss of the overstory canopy (i.e., ≥ 90%
 mortality) were relatively small (&lt; 0.24 km2) and isolated
 throughout the study area. Our findings help to inform an understanding of
 the variable effects of bark beetle outbreaks across complex forested
 regions and provide insight into patterns of disturbance legacies,
 landscape connectivity, and susceptibility to future disturbance.
description: Data were collected using a range of techniques. Field data
 include 239 field inventory plots of live and dead forest structure in
 sites affected by bark beetles c. 1990s to 2010s. Spatial data include
 spectral indices derived from Landsat time series, calculated using the
 Google Earth Engine implementation of the LandTrendr temporal segmentation
 algorithm. Data were processed by summarizing the total
 live and dead tree basal area in each field plot, and converting these
 numbers to percent basal area mortality. LandTrendr products were
 extracted to each field plot by summing the magnitude of all identified
 spectral declines from 1996-2019 for each spectral band/index at each
 field plot location. For information on data
 processing, see "README.md" and refer to the original
 paper.
description: We place no restrictions on the use of these data. See
 "README.md" and original paper for usage notes. Please contact
 the study authors with any additional questions regarding the use of these
 data.