What determines the effectiveness of pinyon-juniper clearing treatments? Evidence from the remote sensing archive and counter-factual scenarios

Reference

Fick, S. E., T. W. Nauman, C. C. Brungard, and M. C. Duniway. 2022. What determines the effectiveness of Pinyon-Juniper clearing treatments? Evidence from the remote sensing archive and counter-factual scenarios. Forest Ecology and Management. 505:119879

Location

Colorado Plateau in the Upper Colorado River Basin above Lake Mead in eastern Utah and western Colorado (a few sites in New Mexico)

Description of Site

Regional study of 302 separate treatment events in 1569 distinct treatment polygons across a broad range of pinyon-juniper woodland communities in the Colorado Plateau.

Treatments

Included prescribed burning, mastication, chaining, hand-cutting, or other, seeded or not; all sites all measured had a single treatment application; Time period – time since treatment 5-30 years, with most treatments applied between 2005 and 2010; Measurements – cover estimates for bare ground, litter, annual forb and grass, perennial forb and grass, shrubs, and trees from the Range Assessment Platform ver. 2

Findings

Authors found evidence that treatments reduced tree cover and largely increased shrub and perennial herbaceous cover for 10 or more years. Treatments were also associated with increases in annuals, most likely non-natives.  Some geometrographic settings were likely to return to pretreatment conditions within 10-15 years, while other settings posttreatment conditions were more persistent.  Despite these trends, authors reported a high degree of unexplained variation that the could not be explained by ecological site factors.

Comments

The overall response of plant cover groups in this paper, which included trees, shrubs, perennial herbaceous, and invasive cover is the most common response to tree removal reported in the literature across the Colorado Plateau and Great Basin. Across the broad range of study sites there was considerable variation in the different plant cover group response across the study area, which obscured the relationship plant posttreatment plant response to ecological site characteristics.

Soils, topography, and climate, play an important role in plant community resilience and resistance to invasives.   However, other factors including treatment type and severity, disturbance histories, pretreatment vegetation, post-treatment management, and weather can blur the relationships between vegetation response and ecological site characteristics.  (see link the description of Primary Components that influence plant succession following disturbance).  Range management has always been a combination of Art and Science, and Art comes largely from personal and others experience in land management.