166 research outputs found
Effects of Leaving Slash in Place Following Ashe Juniper Thinning from Texas Hill Country Grasslands
No full textThe Edwards Plateau of Central Texas exemplifies the global phenomenon of indigenous woody plant encroachment into grasslands. The present study in Blanco County investigates a grassland management technique where felled Ashe juniper (Juniperus ashei) trees are left in place after cutting. This method, coined 'The Juniper Blanket’, has anecdotally shown to stabilize the soil, reduce erosion, and provide favorable conditions for grass growth as well as desirable woody species. Treatment plots (n = 18) consisting of Ashe juniper removal, Ashe juniper blanket, and control plots were established in both a woodland as well as a grassland setting and monitored from March 2017 to March 2018. This study compared species richness (S), Simpson’s Index of diversity (D), and Shannon’s index of diversity (H) calculated from percent cover in the treatment areas. In addition to monitoring plant assemblage, soil moisture and the soil seed banks was examined. Following four months of observation, no taxa emerged from the soil seed bank. Trends in soil moisture were generally higher under the Ashe juniper blanket plots as compared to both the Ashe juniper removal plots and the control plots in the woodland. Biodiversity measures (S, D, H) all increased where the Ashe juniper blanket was applied in the woodland (p ≤ 0.05). However, these trends were not seen in the grassland plots. These findings suggest that the juniper blanket method may be an effective method of restoring or converting juniper woodlands to grassland communities in the Edwards Plateau.Integrative Biolog
Habitat Restoration of Pinyon-juniper Woodlands and its Impact on Avian and Plant Communities
No full textPinyon-juniper woodlands are a vast vegetation community that is vital to the south western United States. Stand characteristics of these woodlands have been impacted by climate, land use practices, and intense fire suppression, causing rapid encroachment of woody plants into grasslands. Throughout New Mexico, efforts are ongoing to restore the Pinyon-juniper woodlands to a historic stand structure and reduce fuel loads. There is a high proportion of avian pinyon-juniper specialists included on national and state lists of concern, including both target species. The Juniper Titmouse (Baeolophus ridgwayi) prefer a mature stand structure of junipers that provide cavities for food storage and nesting. The Gray Flycatcher (Empidonax wrightii) occupies pinyon-juniper woodlands, and in the northern extent of its range, it occupies open Ponderosa pine forests with grasslands. As the vegetation community changes, so will avian communities. So, we have partnered with the U.S. Bureau of Land Management and the U.S. Fish and Wildlife Service and my goal is to study how avian community composition changes in concert with changes to the vegetation community following thinning. We stratified our random sampling into treated and control plots and established abundance of key species based on detection probabilities. We conducted point count surveys during the breeding seasons of 2021 - 2022 at a site in Lincoln County, NM. This project is ongoing as the first component of a longer study to understand time-lags associated with both avian and vegetation response to landscape level management actions.Embargo status: Restricted until 09/2028. To request the author grant access, click on the PDF link
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How to: pinyon pine & juniper
No full textThe following brochure offers information on the management and treatment of burned pinyon pine and juniper trees on private property
Juniper Effects on Grassland Soil Nutrient Availability
No full textabstract: ABSTRACT The February 2008 study of a Snowflake, Arizona site measured changes in soil organic carbon, total nitrogen, extractable phosphorus, and soil moisture, to determine what affect One-seed Juniper (Juniperus monosperma) trees have on surrounding soil, thus affecting native grass growth. Increasing juniper densities in grasslands also decrease populations of some grassland bird species. Measurements were taken each meter along a twelve meter line transect, moving from juniper trees, through a bare soil area and into a grassland. Non-linear relationships were examined, in regard to distance from the tree and juniper root mass. Relationships were examined to determine any affect of the juniper tree on soil characteristics along the transect. Organic carbon decreased as distance increased from the trees (F=4.25, df=46, p=0.020). Soil moisture increased with distance from the trees (F=5.42, df=46, p=0.008), and juniper root mass, of roots less than 1 mm diameter, significantly decreased with distance away from the trees (F=11.29, df=46, p=0.0001). Total nitrogen and extractable phosphorus did not significantly change with distance from the tree, or presence of juniper roots. This data is important as grassland restoration projects rely on the availability of soil nutrients and water for reestablishment of native grass species.Dissertation/ThesisM.S. Applied Biological Sciences 201
Unknown physico-chemical properties of wood and the uses of common juniper (Juniperus communis L.)
No full textAuthor reports on physico−chemical properties and the uses of juniper wood, tar and etheric oils obtained from juniper wood and fruits
Spatial and temporal controls on pinyon and juniper seedling establishment in the Uncompahgre Plateau, western Colorado
No full text2012 Summer.Includes bibliographical references.Moderate and extreme climate events have the potential to cause sudden shifts with long-lasting relictual effects in ecological communities. In this study I investigated the direct and indirect effects of climate on Colorado pinyon (Pinus edulis) and Utah juniper (Juniperus osteosperma) on the Uncompahgre Plateau in western Colorado. I determined age structure of pinyon seedlings and tested for the effects of current year and antecedent year climate on seedling establishment. Finally, I described microhabitat preferences (substrate microhabitat and overstory canopy) for pinyon and juniper seedlings and assessed whether suitable microhabitats may have changed as a consequence of overstory die-off. No relationships between climate and pinyon establishment were detected, and pinyon establishment appears to have been relatively constant over the past 30 years. I found that both pinyon and juniper exhibited distinct preferences for certain substrate microhabitats, especially different types of litter. Pinyon seedlings avoided bare soil microhabitats. While both pinyon and juniper seedlings avoided open overstory microhabitat, pinyon preferred juniper overstory microhabitat. Microhabitat preferences of pinyon seedlings may buffer seedlings from climate-induced stress. Pinyon overstory declined rapidly due to a severe drought from 2000-2004, but juniper overstory was not affected. My results indicate that episodic overstory mortality events and continuous pinyon establishment characterize pinyon dynamics on the Uncompahgre Plateau, at least within the 30 year time frame investigated here. In contrast, juniper seedlings are less abundant but likely more resilient to climate-induced changes in microhabitat structure. Future pinyon establishment and overstory survival may be reduced due to direct and indirect effects of climate, especially if predictions for increased drought frequency and severity for this area are realized
The quiet invasion: managing juniper in eastern Oregon
No full textSince Euro-American settlement, western juniper has steadily encroached on the eastern and central Oregon landscape, taking over productive grasslands, aspen stands, and other ecosystems. To improve water quality and quantity, restore native ecosystems, and provide for the needs of both livestock and wildlife, there has been an increasing effort to control Juniper in Central and Eastern Oregon. These clips explore the history, science, and management concepts behind the decision by many local landowners, and federal and state agencies to actively manage their lands to confront the juniper issue. Through interviews with local ranchers, land managers, scientists, and government officials, "The Quiet Invasion" explores why the decision was made to cut down juniper on some sites, and to use prescribed fires and other management techniques when necessary.Part 1 -- Part 2 -- The Rancher Perspective -- Tools for Managers -- Alternative Uses for Juniper.This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Writers Jeff Hino, Mark Reed; editors Steve Cox, Jeff Hino; videography Jeff Hino, Mark Reed; additional videography Roxane Bailey; narrator Jeff Hino.Funded by Oregon Watershed Enhancement Board, Bureau of Land Management, Burns District, Eastern Oregon Agriculture Research Center, Harney County Court, U.S.D.A. Forest Service.Mode of access: Internet from the Oregon Government Publications Collection.In English
Effects of juniper woodland expansion on breeding birds in grasslands of northern Arizona
No full textabstract: Since European settlement, pinyon-juniper woodlands have expanded into large portions of the southwestern United States historically occupied by grassland vegetation. Because grassland bird species are closely tied to vegetation structure, woodland expansion can substantially change the composition of breeding bird communities.Technical guidance bulletin ; no. 1Includes bibliographical references (p. 14-16)
Post-fire vegetation and bird habitat use in piñon-juniper woodlands
No full text2022 Spring.Includes bibliographical references.Global climate change has caused fire activity and behavior to shift from historical norms due to hotter and drier conditions. Although the ecological effects of changing fire regimes have been explored in many systems, the resilience of some forest types, such as piñon-juniper, are often overlooked. Piñon-juniper is a dominant forest type in the western US and provides breeding habitat for many obligate or semi-obligate bird species. Similarly, this system is supported by a critical mutualism, where the regeneration and infilling of these trees is reliant on several bird species that disperse piñon pine and juniper seeds. This study aimed to assess woodland resilience by evaluating post-fire forest structure and the associated avian communities one-year and 20+ years post-fire. More specifically, seedling regeneration and the habitat use of piñon-juniper obligate bird species, semi-obligates, piñon seed dispersers, and juniper seed dispersers were compared across burned, refugia, and unburned patches. Replicate patches of each habitat type were selected within three fire locations, and 3-4 bird point count stations and 1 forest inventory plot were established in each patch. No tree regeneration was observed 1-year post-fire, and after 25 years, there were few juniper seedlings and no piñon seedlings observed in burned plots. Seedling regeneration and forest structure in refugia and unburned plots were not different, regardless of fire age. Results from occupancy models indicated that Woodhouse's Scrub-jay, a piñon seed disperser, used all habitats equally. American Robin had the highest habitat use in the recent burned patches. Obligate and semi-obligate bird species had differing responses to habitat types, with the habitat use of Ash-throated Flycatcher and Spotted Towhee not differing across habitat types, Virginia's Warbler having the highest habitat use in old burn and refugia patches, the Gray Vireo, Black-throated Gray Warbler, and Gray Flycatcher having highest habitat use in unburned, refugia, and recent burn patches, and the Blue-grey Gnatcatcher having the highest habitat use in the old burn. While there is a need for longer term studies, our work highlights that even 25 years post-fire, little tree recovery is observed and the associated bird species continue to differ, emphasizing the potential transition or long recovery time in these sensitive areas
Vegetation Community Responses to Juniper Slash/Burn and Broadcast Burn on A Semi-Desert Tobosa Grassland
No full textabstract: ABSTRACT
Modern management techniques to maintain rangelands and deter encroachment of juniper into grassland habitats currently includes fire prescription. Additionally, a large body of research has indicated that fire has multiple benefits to grasslands resulting in increased diversity of flora and fauna. In the semi-arid grassland of the Agua Fria National Monument, fire treatments may be able to provide similar advantages. This study considers two methods of fire prescription on the Agua Fria National Monument within central Arizona: 1) Juniper thinning with pile burning; 2) Broadcast burning.
The Agua Fria National Monument upland ecosystem has limited research focusing on semi-arid grassland and juniper stand’s response to implemented treatments over time. The four year monitoring duration of this study aids in assessing the outcome of treatments and reaching the objectives of the management plan.
Vegetation in 981 quadrats was measured for species richness, cover, densities, height, and biomass during the fire prescription period from 2009 through 2013. The study was divided into two treatment types: 1) Juniper cutting and pile burn; 2) Broadcast burn areas in open grasslands.
Results of this study provide consistent examples of vegetative change and community movement towards positive response. Percent composition of overall vegetation is 5 – 30% with >50% of litter, bare ground and rock cover. Juniper sites have immediate consequences from tree thinning activities that may be beneficial to wildlife, particularly as connective corridors pronghorn antelope. Grass height was significantly reduced as well as forb density. Forbs that are highly responsive to environmental factors indicate an increase after the second year. Analysis results from grasslands indicated that cactus and unpalatable shrubs are reduced by fire but a return to pre-burn conditions occur by the third year after fire disturbance. Percent cover of perennial grasses has shown a slow increase. Wright’s buckwheat, a palatable shrub, has increased in density and height, indicating fire adaptations in the species. Species richness was reduced in the first year but increase in density continues into the third year after burn.Dissertation/ThesisMasters Thesis Applied Biological Sciences 201
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