Data from: Limited conifer regeneration, but widespread regeneration of aspen seedlings following the Cameron Peak Fire, northwestern Colorado

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 >50 m and <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.