DOI: 10.5061/dryad.8931zcrm7
title: Data from: The 15-year post-treatment response of a mixed-conifer understory plant community to thinning and burning treatments

description: Disturbance is central to maintaining diversity in forest ecosystems. In
 the dry forests of the western United States, over a century of fire
 exclusion has altered the fire regimes of these forests, resulting in high
 fuel loads and a loss of plant diversity. Mechanical thinning and
 prescribed fire are widely used to restore structural complexity and
 species diversity in many western U.S. forests. While studies have shown
 that the reintroduction of fire into these forests initially promotes
 plant diversity, there is limited information on the persistence of this
 effect. We evaluated the effects of thinning and burning treatments on the
 understory plant community fifteen years after treatment in an old-growth,
 Sierran mixed-conifer forest. Using a full-factorial design, including
 three levels of thinning and two levels of burning, we found mechanical
 thinning and prescribed fire reduced litter depths and increased the
 availability of bare ground, resulting in an initial increase in herb
 cover. However, fifteen years after treatment, litter depths and shrub
 cover increased, resulting in a more homogenous understory community and a
 loss of herb cover. Overall, our results suggest that while thinning and
 burning treatments initially promote herbaceous plant cover, these effects
 are short lived in the absence of a second disturbance.
description: These data are the supporting vegetation data for:
 Goodwin, MJ, MP North, HSJ Zald, MD Hurteau. 2018. The 15-year
 post-treatment response of a mixed-conifer understory plant community to
 thinning and burning treatments. Forest Ecology and Management
 429:617-624. The Understory Vegetation data contain
 gridpoint data for all 402 gridpoints for each measurement year.
 The measurement years include: 2001, 2002, 2003, 2004 and 2006
 (2, 3, 4 and 6 years post-treatment), 2011, 2012 and 2013 (11, 12 and 13
 years post-treatment),<br> and 2016 and 2017 (16 and 17 years
 post-treatment). The following variables were assessed
 at each gridpoint: Percent cover of all species present
 (recorded in columns with species code) Total Plant
 Cover Percent cover of bareground (bare ground =
 mineral soil) Percent cover of rock (any exposed rock
 larged than a marble) Average litter depth (average of
 three litter depth measurements) Percent cover of
 sticks (any piece of wood larger than 2 cm diameter (approx. the size of
 an index finger) and smaller than 7 cm in diameter)
 Percent cover of Coarse Woody Debris decay class 1 to 3 (any
 piece of wood larger than 7 cm in diameter with wood still intact. You
 could step on it or poke it with a ruler and not sink into the
 wood) Percent cover of Coarse Woody Debris decay class
 4 and 5 (any piece of wood larger than 7 cm in diameter with wood
 beginning to fall apart. If you stepped on it or poked it, it would fall
 apart) <br> Cover values were recorded as
 follows: 0.1-0.9 % cover – record by 0.1 (0.1, 0.2, 0.3
 etc.). 0.1 indicates a species is present.  Use this value even if the %
 cover is less than 0.1 1-10 % cover-record as whole
 numbers (1,2,3 etc.) 10-100% cover- record as a
 multiple of 5 (15,20,25 etc.) <br> The Treatment
 Codes refer to the following Treatments: BC =
 Burn/Understory Thin<br> BN = Burn Only<br> BS =
 Burn/Overstory Thin<br> UC = Understory Thin<br> UN =
 Control<br> US = Overstory Thin