Understory Cover Responses to Piñon–Juniper Treatments Across Tree Dominance Gradients in the Great Basin

Influence of Wildland Fire Along a Successional Gradient in Sagebrush Steppe and Western Juniper Woodlands

“…From a perspective of restoring sagebrush ecosystems, management practices aimed at thinning pinyon-juniper trees in CC2 and CC3 (without removing all trees) are commonly conducted with intent of reducing woody fuel loads and wildfire risk Roundy et al, 2014aRoundy et al, , 2014b, increasing soil moisture retention (Roundy et al, 2014b), improving understory conditions Miller et al, 2014;Roundy et al, 2014a), and improving health and vigor of individual trees (Page, 2008). Because CC2 areas are also codominated by sagebrush, complete removal of trees in these areas would likely make more sagebrush habitat available to sage-grouse, assuming space formerly occupied by trees is not invaded by annual grass (Davies et al, 2011).…”

Cover Estimations Using Object-Based Image Analysis Rule Sets Developed Across Multiple Scales in Pinyon-Juniper Woodlands

“…In particular, 3 to 4 yr after treatment, neither native perennial grasses nor forbs differed from controls in treeless Wyoming sagebrush, but both increased significantly in Wyoming sagebrush/woodland and mountain sagebrush/woodland (Table 2). Resilience after fire was generally lower because of the removal of both shrubs and trees, and resilience was lower on plots that initially had higher cover of trees, due to lower perennial bunchgrass cover before treatment (Chambers et al 2014a). However, even in plots with high tree cover, bunchgrass cover increased by 3 yr both after fire and after mechanical treatment, and was trending higher with time (Roundy et al 2014a;Fig.2).…”

“…Retaining adequate perennial herbaceous cover in the face of potential invaders is an important part of resistance in the sagebrush steppe system. SageSTEP treatments allowed us to assess resilience and resistance for various disturbances and across gradients of tree encroachment or cheatgrass invasion (McIver et al 2010), and across soil moisture and temperature regimes (Chambers et al 2014a). Resilience generally increased from warm/dry (mesic/ aridic) Wyoming big sagebrush (Artemisia tridentata subsp.…”

“…Neither native perennial grass species composition nor big sagebrush subspecies had as much influence on resistance as did soil temperature and moisture regimes. For example, the Stansbury site had relatively low resistance to cheatgrass, despite having mountain big sagebrush as the dominant shrub, because this site is relatively warm and thus susceptible to cheatgrass invasion (Roundy et al 2014a). In contrast, the other woodland sites dominated by mountain big sagebrush were relatively cool and moist, and typically had high resistance to cheatgrass (Chambers et al 2014a).…”

“…Restoration practices have the potential to alter fuel beds and decrease future fire suppression costs (Taylor et al 2013), lower competitive suppression of perennial bunchgrass species, and decrease longer-term risk of cheatgrass dominance (Chambers et al 2014a). Substantial published information exists on the efficacy of such treatments in sagebrush steppe, but most studies are site-specific, short-term (Miller et al 2013), and focused on few variables.…”