Treesearch

Mastication and hand-thinning treatments are increasingly used by land managers as a means of reducing tree cover for fire hazard mitigation and other habitat objectives in pinon-juniper (P-J) woodlands. (Battaglia et al. 2010; Redmond et al. 2013). However, the effects of these treatments on ecological processes including fire, and on a wide range of species, particularly vulnerable P-J obligate birds, are incompletely understood. To address these knowledge gaps, we measured vegetation and fuels, and conducted bird point counts at 232 sites in 29 pairs of 1 to 11-yearold treatments and...

Small-scale (< 5 ha) tree thinning treatments were implemented at two pinyon-juniper (Pinus edulis-Juniperus monosperma) and two ponderosa pine (Pinus ponderosa) wildland-urban interface woodland sites in central New Mexico. We used paired watershed, Before/After/Control/Impact sampling designs with 3 years of prethinning measurements followed by 5 years of posttreatment measurements. Characteristics of soils, vegetation, and wildlife were measured. Manual thinning treatments reduced small trees, removed firewood, and chipped slash. The treatments reduced wildfire fuel loads, changed the...

Pinon-Juniper vegetation covers 100 million acres across the western United States, in areas of diverse topography, climate, and soils. Consequently, Pinon-Juniper vegetation varies greatly in structure and disturbance processes at both the stand and landscape scales. Until recently, however, this variation was not widely recognized, and Pinon-Juniper vegetation was interpreted and managed in much the same way throughout its range (Jacobs 2008a). Early studies were conducted primarily in the Great Basin and Mexican borderlands, where juniper expansion into grasslands and shrublands was a...

Colorado pinyon pine (Pinus edulis) forms mutualistic associations with root-associated ectomycorrhizal (EM) fungi which confer improved fitness under stressful conditions and thus may be critical to the success of this species in response to global climate change. We review studies of the EM fungal associations of P. edulis with an emphasis on the literature focused on drought and associated P. edulis mortality. We also describe the importance of other soil microbes including nonmycorrhizal fungi and bacteria, and present data describing dominant soil microbial taxa associated with P....

Severe droughts in the southwestern USA in 2002- 2003 revealed that pinyon pine and juniper trees are susceptible to widespread mortality caused by severe water deficits and drought-facilitated insect outbreaks (Breshears et al., 2005; Clifford et al., 2008). Despite increased interest in forest susceptibility to drought, the influence of stand structure on the drought resilience of pinyon-juniper woodlands remains uncertain (Meddens et al., 2015). Stand structure is of particular interest because it is readily manipulated by silvicultural practices such as thinning. Page (2008) suggests,...

Wildlife managers are concerned about the impacts of climate change on Pinon-Juniper habitats and on the ecosystem services that they provide (Friggens et al. 2013). Contrary to common perception, this extensive ecosystem type is greatly varied in structure, composition, ecology, and habitat value (Comer et al. 2003; Moir and Carlton 1986; Romme et al. 2009), along with the expected manifestations of climate change vulnerability (Comer et al. 2012; Rehfeldt et al. 2006). This work resulted in a geospatial climate vulnerability surface that included five types of Pinon-Juniper across...

Pinon-Juniper (PJ) ecosystems cover approximately 30 million ha in the western United States (West 1999). High variability in species assemblages and structure exists across this large geographic range, driven in part by varying climate. Among the three functional PJ types (persistent PJ woodlands, PJ savannas, and PJ shrublands), the least is known about ecosystem processes and vegetation dynamics in PJ ecosystems containing a substantial grass component - PJ savannas (Romme et al. 2009).

Pinyon Jays and piñon pines have a mutualism whereby the trees provide mast crops of highly nutritional seeds that enhance the jays’ population viability (Marzluff and Balda 1992), and the jays cache the seeds, serving as the tree’s main long-distance seed disperser (Ligon 1978). Breeding Bird Survey data indicate that Pinyon Jay populations have been declining for 50 years (Sauer et al. 2014), and they are currently the fastest-declining Pinon-Juniper bird species (Boone et al. in press). Ongoing decline of the piñon tree’s main seed disperser will limit the potential of the trees to...

Characterization of shifts in regional hydroclimatic conditions helps reduce negative consequences on agriculture, environment, economy, society, and ecosystem. This study assesses shifts in regional hydroclimatic conditions across the conterminous United States in response to climate change over the 21st century. The hydrological responses of five downscaled climate models from the Multivariate Adaptive Constructed Analogs data set ranging from the driest to wettest and least warm to hottest were simulated using the variable infiltration capacity (VIC) model. Shifts in regional hydroclimat...

The 2012 Planning Rule requires that National Forest planning teams provide for a transparent, collaborative process that allows effective public participation, but there is no roadmap for how to be successful. A recent General Technical Report describes how Q methodology can collect stakeholder input in a way that is engaging, thorough, and scientifically rigorous. This process can help forest planners identify different perspectives as well as areas of agreement by stakeholders, including the public.