DOI: 10.5061/dryad.x3ffbg7zx
title: Data from: Limited conifer regeneration, but widespread regeneration of aspen seedlings following the Cameron Peak Fire, northwestern Colorado

description: Changing fire regimes and climate conditions have decreased postfire
 conifer regeneration densities in many ecosystems across western North
 America. In the Southern Rocky Mountains, sparse postfire regeneration of
 conifers has often been accompanied by abundant regeneration of quaking
 aspen, much of which is from vegetative resprouting. While aspen also
 produces abundant lightweight seed that can disperse great distances, we
 know considerably less about the patterns and drivers of postfire
 establishment of aspen from seed. To understand the potential for severe
 fire to catalyze shifts to aspen-dominated forests, we surveyed tree
 regeneration at 34 sites across upper montane and subalpine forests that
 burned in the Cameron Peak Fire located in northern central Colorado. All
 sites were located in areas that: (a) burned at high or moderate severity
 and (b) were located &gt;50 m and &lt;1000 m away from a pre-fire
 patch of aspen. At each site, we recorded the coordinates, elevation,
 slope, aspect, and pre-fire tree-species composition. Tree regeneration
 was then surveyed in two perpendicular 2 x 50 m transects that intersected
 at the midpoint. Two years following fire, we found widespread but highly
 variable establishment of aspen seedlings, despite the absence of aspen in
 the pre-fire stand. Aspen seedlings were more likely to occur at higher
 elevations, where they were often clustered within concave microsites with
 bryophyte substrates and near large coarse woody debris. Further we found
 aspen seedlings often outnumbered conifer seedlings and occurred within
 the same local neighborhood as conifer seedlings.
description: # Data from: Limited conifer regeneration, but widespread regeneration of
 aspen seedlings following the Cameron Peak Fire, northwestern Colorado ##
 **Authors and Affiliations** ## Authors Sarah V. Carter^1^ and Sarah J.
 Hart^1^ ## Affiliations 1 - Department of Forest and Rangeland
 Stewardship, Colorado State University, 1472 Campus Delivery, Fort
 Collins, CO 80523, USA Corresponding author: Sarah J. Hart (email:
 [sarah.hart@colostate.edu](mailto:sarah.hart@colostate.edu)) ## Dataset
 Description ### Summary This dataset contains the data required to
 replicate analyses in Carter and Hart (in review), which examines the
 patterns and drivers of postfire seedling establishment of aspen at 34
 sites within the burn scar of the Cameron Peak Fire, northwestern
 Colorado. Data was collected in the summer of 2022. ### Research context
 To understand the potential for severe fire to catalyze shifts to aspen
 dominated forests, we studied recently burned conifer-dominated forests
 and asked (1) how does postfire regeneration of conifers and aspen vary
 across sites? (2) how are aspen and conifer seedlings distributed within
 sites? and (3) how do site and microsite conditions influence aspen
 seedling establishment? ## Geographic Coverage * **Location**: Cameron
 Peak Fire scar * **Latitude/Longitude Bounding Box**: -105.90370,
 40.46133, -105.19902, 40.77812 * **Elevation range**: 2462-3255 m *
 **Habitat/Ecosystem Type:** upper montane and subalpine forests ## Data
 Collection Methods ### Study sites Sites were randomly located using
 geospatial data describing the extent and severity of the Cameron Peak
 Fire from the Monitoring Trends in Burn Severity (MTBS) Project (2024b,
 2024a) and the extent of pre-fire aspen cover from Cook et al. (2024). We
 combined these data sources to identify areas that: (a) burned at high
 severity and (b) were located &gt;50 m and &lt;1000 m away from a pre-fire
 patch of aspen. Sites were further limited to accessible areas, defined as
 public land within 1000 m of a road or 500 m away from a trail and no more
 than 1 km up the trail. To reduce the potential effects of
 psuedoreplication, all sites were located &gt;400 meters apart. ### Field
 data collection At each site, we recorded the coordinates, elevation,
 slope, aspect, and pre-fire tree-species composition. We then established
 two perpendicular 2 x 50 m transects that intersected at the midpoint
 (Andrus et al. 2021). We tallied the presence of all conifer seedlings,
 aspen seedlings, and aspen root suckers within each transect and recorded
 their location along the transect within 2 x 2m subplots. Aspen seedlings
 were differentiated from root suckers using methods outlined by Kreider et
 al. (2020), which have been demonstrated to be more than 95% accurate
 (Kreider et al. 2021) and were shown to be effective in our study area
 (Carter 2024). Along each transect, we also collected information on
 percent, forb, shrub, graminoid, and total herbaceous cover in three 1 x 1
 m quadrats located every 20 m along each transect. We additionally
 recorded information on proximity to coarse woody debris, substrate
 conditions, and microtopographic condition for each aspen seedling. We
 characterized the microtopography as flat, concave, or convex within 2.5
 cm of seedling (hereafter ‘small microtopography’) and within 50 cm of
 seedling (hereafter ‘large microtopography’). We also recorded the
 presence or absence of small (diameter = 2.5-10 cm) and large (diameter
 &gt;10 cm) coarse woody debris (CWD) within 10 cm of seedling. We also
 collected microsite conditions at 5 meter intervals along each transect to
 serve as a baseline of the relative abundance each condition across the
 site. ## Data files The dataset consists of the following files *
 *Site.csv* : This data includes the geographic characteristics of each
 site sample. * *PrefireOverstory.csv* : This data includes information on
 the presence/absence of each tree species within a 20 m plot centered at
 the midpoint. * *Understory.csv* : This data includes information on the
 understory percent cover, which was collected in three 1 x 1 m quadrats
 located every 20 m along each transect. * *SeedlingDensity.csv* : This
 data includes post-fire regeneration densities collected in two
 perpendicular 2 x 50 m transects that intersected at the midpoint. *
 *SeedlingMicrosite.csv* : This data includes information on the microsite
 conditions for each aspen seedling we observed. * *SiteMicrosite.csv* :
 This data includes microsite conditions collected at 5 meter intervals
 along each transect and serves as a baseline of the relative abundance
 each condition across the site. * *README.md* : This file. ## Variable
 descriptions ### Site.csv * **Site**: Unique ID for each site *
 **UTM.zone**: the UTM zone of the site * **Easting:** Easting of the site
 (m) * **Northing:** Northing of the site (m) * **Elevation:** Elevation of
 the site (m) * **Slope**: slope of the plot in degrees * **Aspect**:
 aspect of the plot in degrees from 0 to 360 * **Topo.Position**:
 topographic position of the plot (level, sloping, or concave) ###
 PrefireOverstory.csv * **Site**: Unique ID for each site * **ABLA**: the
 presence (1) or absence (0) of subalpine fir (*Abies lasiocarpa*) in the
 pre-fire site * **PICO**: the presence (1) or absence (0) of lodgepole
 pine (*Pinus contorta*) in the pre-fire site * **PIEN**: the presence (1)
 or absence (0) of Engelmann spruce (*Picea engelmanniii*) in the pre-fire
 site * **PIPO**: the presence (1) or absence (0) of ponderosa pine (*Pinus
 ponderosa)* in the pre-fire site * **PSME**: the presence (1) or absence
 (0) ofcount of Douglas fir (*Psuedotsuga menziesii*)in the pre-fire site
 ### Understory.csv * **Site**: Unique ID for each site * **Transect**: ID
 for the transect (either A or B) * **Point**: the distance (m) along
 transect where the data were collected (0, 20, or 40) * **Forb**: the
 percent cover of forbs (0-100) * **Shrub**: the percent cover of shrubs
 (0-100) * **Gram**: the percent cover of graminoids (0-100) * **Herb**:
 the percent cover of graminoids (0-100) ### SeedlingDensity.csv *
 **Site**: Unique ID for each site * **Transect**: ID for the transect
 (either A or B) * **Subplot**: ID for the subplot * **ABLA**:count of
 subalpine fir (*Abies lasiocarpa*) seedlings per subplot * **PICO**: count
 of lodgepole pine (*Pinus contorta*) seedlings per subplot *
 **PIEN**:count of Engelmann spruce (*Picea engelmanniii*) seedlings per
 subplot * **PIPO**: count of ponderosa pine (*Pinus ponderosa)* seedlings
 per subplot * **PSME**: count of Douglas fir (*Psuedotsuga
 menziesii*)seedlings per subplot * **POTR5.sucker**: count of trembling
 aspen (*Populus tremulodies)* suckers per subplot *
 **POTR5.seedling**:count of trembling aspen (*Populus tremulodies)*
 seedlings per subplot * **Conifer**: count of conifer seedlings per
 subplot ### SeedlingMicrosite.csv * **Site:** Unique ID for each site *
 **Transec**t: ID for the transect (either A or B) * **Subplot**: ID for
 the subplot * **Height**: seedling height (cm) * **Substrate**: the
 dominant substrate on which the seedling was found (bryophytes, char,
 litter, mineral soil, rock, wood) * **Small.Topo**: the local topography
 within 2.5 cm of the seedling (concave, level, sloping) * **Large.Topo**:
 the local topography within 50 cm of the seedling (concave, level,
 sloping) * **Large.CWD**: the presence (1) or absence (0) of coarse woody
 debris &gt;10 cm in diameter * **Small.CWD**: the presence (1) or absence
 (0) of coarse woody debris 2.5-10 cm in diameter * **Sucker.Dist**: the
 distance to the nearest aspen sucker * **Browse**: the presence (1) or
 absence (0) of browse damage ### SiteMicrosite.csv * **Site**: Unique ID
 for each site * **Transect**: ID for the transect (either A or B) *
 **Point**: the distance (m) along transect where the data were collected
 (0, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50) * **Substrate**: the
 dominant substrate on which the seedling was found (bryophytes, char,
 litter, mineral soil, rock, wood) * **Small.Topo**: the local topography
 within 2.5 cm of the seedling (concave, level, sloping) * **Large.Topo**:
 the local topography within 50 cm of the seedling (concave, level,
 sloping) * **Large.CWD**: the presence (1) or absence (0) of coarse woody
 debris &gt;10 cm in diameter * **Small.CWD**: the presence (1) or absence
 (0) of coarse woody debris 2.5-10 cm in diameter * **Sucker.Dist**: the
 distance to the nearest aspen sucker ## Data Usage Notes * missing values
 are coded as `NA` ## Related publications Carter, S. V. and Hart, S. J.
 (in review). *Limited conifer regeneration, but widespread regeneration of
 aspen seedlings following the Cameron Peak Fire, northwestern Colorado.*
 ## Data Citation Carter, S. V. and S. J. Hart. 2025. Data from: Limited
 conifer regeneration, but widespread regeneration of aspen seedlings
 following the Cameron Peak Fire, northwestern Colorado. Dryad.
 [https://doi.org/10.5061/dryad.x3ffbg7zx](https://doi.org/10.5061/dryad.x3ffbg7zx) ## License This dataset is released under the **Creative Commons Zero (CC0) Public Domain Dedication**, per Dryad policy. ## References Andrus, R. A., S. J. Hart, N. Tutland, and T. T. Veblen. 2021. [Future dominance by quaking aspen expected following short-interval, compounded disturbance interaction](https://doi.org/10.1002/ecs2.3345). Ecosphere 12:e03345. Cook, M., T. Chapman, S. Hart, A. Paudel, and J. Balch. 2024. [Mapping Quaking Aspen Using Seasonal Sentinel-1 and Sentinel-2 Composite Imagery across the Southern Rockies, USA](https://doi.org/10.3390/rs16091619). Remote Sensing 16:1619. Kreider, M. R., K. E. Mock, and L. L. Yocom. 2020. [Methods for Distinguishing Aspen Seedlings from Suckers in the Field](https://doi.org/10.1093/jofore/fvaa030). Journal of Forestry:fvaa030. Kreider, M. R., and L. L. Yocom. 2021a. [Low-density aspen seedling establishment is widespread following recent wildfires in the western United States](https://doi.org/10.1002/ecy.3436). Ecology 102:e03436. MTBS Project. 2024b. [MTBS data access: Burned severity mosaics dataset](https://mtbs.gov/direct-download). MTBS Project. 2024a. [MTBS data access: Burned area boundaries dataset](https://mtbs.gov/direct-download).