The 15-year post-treatment response of a mixed-conifer understory plant community to thinning and burning treatments

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 c..., 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),
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 ...,