Source: UNIVERSITY OF NEVADA submitted to NRP
QUANTIFYING THE IMPACT OF PINYON-JUNIPER REMOVAL ON CURL-LEAF MOUNTAIN MAHOGANY STANDS AND POTENTIAL MULE DEER HABITAT
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
1019900
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jul 1, 2019
Project End Date
Jun 30, 2022
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF NEVADA
(N/A)
RENO,NV 89557
Performing Department
Natural Resources & Environmental Sciences
Non Technical Summary
Mountain mahogany can be found on Nevada mountains, in areas occupied by sagebrush and pinyon-juniper woodlands as well as higher up. Information on the ecology of mountain mahogany is not as deep and comprehensive as for other woody species in the Great Basin. We know, for example, that mule deer uses mahogany as a food source and also for cover. We also know that mahogany trees can be quite old, and that they are often in competition with pinyon-juniper trees, but we need more accurate data on how mahogany trees grow to evaluate their overall contribution to Nevada's rangelands. The age distribution of mahogany stands, the rate at which they grow, the years when most individuals become established, and the relationship between size and age are not well documented. Having reliable data on those processes could change our understanding of how to maintain and improve rangelands on Nevada's mountain ranges. For example, public and private landowners planning pinyon and juniper removal projects may be able to prioritize projects not just for greater sage-grouse, but also for releasing mountain mahogany, which in turn may improve soil fertility and provide food for mule deer populations. Therefore, our project is directly related to the research priorities identified this year by the Nevada Agricultural Experiment Station (NAES). In particular, we will contribute information that is relevant to animal (mule deer) nutrition and health, and we will generate data from mahogany tree rings that are directly related to the impact of climate variability and change on Nevada's vegetation.This interdisciplinary project will be conducted by three faculty members from two CABNR departments, together with two research scientists also from two CABNR departments. The research collaboration will be 3 years in duration and will allow training a graduate student as well as a few undergraduate students.
Animal Health Component
40%
Research Effort Categories
Basic
60%
Applied
40%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1210720107050%
2060710102050%
Goals / Objectives
The overarching goal of this project is to expand our understanding of the ecology of curl-leaf mountain mahogany, including herbivory, in the context of pinyon and juniper encroachment. Objectives in support of this goal include:Identify and characterize vegetation and soil of current stands of mahogany in the Desatoya Mountains.Determine if mahogany tree rings are truly annual increments, and then use dendrochronological methods to quantify age structure, population dynamics, and climate impacts.Quantify mahogany tree and understory response to removal of pinyon and juniper.Clarify if wildlife browse of mountain mahogany differs under pinyon and juniper canopy vs. open stands.Use project results to verify and improve state and transition models in Major Land Resource Area 28B as well as other MLRAs with mahogany sites in central and northern Nevada.Develop a technical guide for land managers and stakeholders on mountain mahogany ecology and management.
Project Methods
Mahogany health and understory dynamicsCut/uncut study locations will be limited to areas in the Desatoya mountain range that have had recent (within 10 years) pinyon and juniper removal treatments. Field reconnaissance of treated areas will be used to finalize site selection. Three cut/uncut paired sites will be selected at first, with the possibility of adding more sites based on initial results and availability of funding. Selected sites shall include live, mature mountain mahogany trees, and should be at least 50 x 50 m in size. We will select sites to capture a spectrum of stand ages, creating a chronosequence.Multiple plots may be established at random locations within the perimeter of the site. At each plot, the following data will be collected:Site and soil characteristics. One soil pit will be dug at each site to a depth of 50 cm or until a hardpan or lithic contact is struck. Soils horizons will be described using the following characteristics and others as needed: texture, rock fragments, pH, depth, soil structure. Slope and aspect will also be recorded.Understory vegetation. At each plot, three 30-m transects will be established, each 10 m apart. The line point intercept method (at 0.5m spacing) will be employed to characterize vegetation by species. Vegetation height and litter depth will be measured at each point. We will use a GRS densitometer to identify overhead tree canopy by species.Woody plant density and age structure. Along each transect, a 2-m belt transect will be used to count individual woody plants rooted within the transect by species and height class and/or maturity class. Depending on vegetation density, the width of the belt transect may be altered. Smaller quadrats (1 m2) will be used along the transect lines to count mahogany seedlings; the number of quadrats per plot will be determined using a sample size equation. At least 5 mahogany stems that cover the full range of sizes present at the site will be cut in each transect for tree-ring analysis. Sections will be taken both at the root crown and at breast height.Mahogany health. Methods for mahogany health are adapted from the USDA Forest Inventory Analysis (FIA) program. In the belt transects, the following metrics will be collected for all live trees with diameter at root crown greater or equal to a minimum threshold (possibly 2.5 cm, but higher if stem density is high): crown density, uncompacted live crown ratio, crown light exposure, crown position (overstory, understory, open canopy), crown vigor class, crown dieback, and foliage transparency.DendrochronologySample preparation. Mahogany sections will be sanded using progressively finer sand paper until cell walls are visible under a 10-30x binocular microscope. Visual crossdating will be performed using ring-width patterns, starting with those in common to 4 radii on a section, and continuing with patterns in common amongst the wood samples, leading to the development of a tree-ring site (or master) chronology. Visual inspection of the ring anatomy will initially be used for discriminating false rings from true annual growth rings, and preliminary dates will be assigned.Radiocarbon dating. Rings that are tentatively dated as years 1955, 1962, 1964, 1966, and 1975, will be manually collected by carefully separating individual growth layers in the tangential direction. Seven radii, each on a different section, will be sampled, for a total of 35 specimens. Individual year collection will end after reaching about 1 g of material. Sample identification codes will be assigned without reference to the tentative calendar years or location in the cross-section. By doing so, the 14C analysis, to be performed at an off-campus laboratory, will not be influenced by prior knowledge on the chronological sequence of the samples.Ring-width measuring. Results obtained from 14C analyses will be used to evaluate the dendrochronological results. Ring-width measurements will then be obtained at 1-µm resolution using the MeasureJ2X software interfaced with a Velmex measuring stage and a videocamera mounted on a stereozoom binocular microscope with 10-70x magnification.Age-size relationship and stand structure. Accurate dates obtained from the previous methodological steps will be used to determine time needed to reach breast height, as well as age-diameter relationships at ground level and at breast height. Using both directly aged trees, and the size-age relationship, we will then determine stand age structure, lifetime growth patterns, and potential recent changes in mahogany productivity and health.Site chronology. A master chronology will be developed from standardized tree-ring indices as follows:Formula 1 (see figures and graphics file)where ?t = chronology value in year t = median annual index; nt = number of samples in year t, with nt≥5; w = crossdated ring width (mm, with 1000th digit resolution) of sample i in year t;y=value of sample i in year t computed by fitting a cubic smoothing spline with 50% frequency response at a period of 100 years to ring width series i; wt/yt = dimensionless index value of sample i in year t. The degree of synchronicity in tree growth patterns will be evaluated using commonly accepted, albeit empirical, parameters, such as the expressed population signal calculated for 30-year moving windows. Sensitivity will be estimated using the Gini coefficient, which considers all possible temporal lags in the tree-ring chronology rather than only the first one, as it is done with mean sensitivity.Dendroclimatic analysis. A comparison will first be conducted with other tree-ring chronologies developed in close proximity to the study area, especially the pinyon tree-ring chronology for the Desatoya Mtns. (1504-2001; Biondi unpublished data). Other chronologies are available from the International Tree-Ring Data Bank as well as from previous DendroLab projects. Growth-climate relationships will be quantified using monthly temperature and precipitation time series starting from Jan 1895, to be extracted from the public-domain, 4-km gridded, PRISM (Parameter-elevation Regressions on Independent Slopes Model) dataset. The temporal stability of statistical relationships will also be evaluated.WildlifeMahogany browse evaluation. An architecture-based browse use method will be used. In year one, quantitative browse history will be completed at all cut/uncut sites. Each sample unit must contain 20 mahogany plants for browse classification. Browse history and current-year browse will be completed during the growing season (June - August) along with other understory measurements.Mule deer demographics. We will use remote cameras to document presence of mule deer in mountain mahogany stands in areas of cut and uncut pinyon-juniper. A grid of cameras will be set up at about 200 m intervals to document mule deer use and movements. While mule deer are present, cameras will be continuously monitoring. Pictures will be collected from cameras every two weeks, and then cameras will be reset. We will use pictures to document sex and age distributions of mule deer and the presence of neonates when possible. Those data will provide information on mule deer demographics in the area. We will use occupancy modeling, and also capture-mark-recapture methods if individuals can be reliably identified.Mule deer diet. Every two weeks throughout the seasons when mule deer are present in the study area we will collect fecal pellets to identify primary forage plants in diet, and we will measure fecal nitrogen as an index of diet quality.

Progress 10/01/20 to 09/30/21

Outputs
Target Audience: Project efforts were able to reach land managers at the Bureau of Land Management, who were involved in providing permits for field sampling. A seminar on how to use radiocarbon dating to test if mountain mahogany tree rings are formed annuallywas presentedto a group of UNR faculty, USDA researchers, graduate and undergraduate students on Dec 3, 2020. Two presentations on project goals/objectives were made to upper-level undergraduate students at UNR. Changes/Problems: Devon Synder, the orginial rangeland ecologist on this project, left UNR in November 2020. Devon's roll in this project was filled by Alexa Lyons. A new manager (Mark Hendrix) has become responsible forSmith Creek Ranch, where our study plots are located. Field contacts and coordination has been maintainedby the Stringham research group. While there have yet been no changes to the project's objectives and/or goals, it is likely that final results and outcomes will be lower than originally expected. What opportunities for training and professional development has the project provided? Seven graduate students (Hondo Brisbin, Jason Gundlach, Lucas Phipps, Juliet Wallis, William Richardson, Morgan Long, Danielle Miles) acquired field and laboratory experience in performing vegetation sampling and wildlife monitoring. One graduate student (Wade Plafcan) received training in tree-ring analysis and radiocarbon dating. Four undergraduate students (Mattie Johns, Alexa Lyons, Tyler Gersbach, Jackson Miller) acquired experience and skills in field sampling and monitoring of vegetation and wildlife. The project provided professional development also for two research technicians (Alexa Lyons and Emily Dietrick), who were hired during this reporting period. How have the results been disseminated to communities of interest? A seminar entitled "Radiocarbon Analysis of Mountain Mahogany (Cercocarpus ledifolius) Tree Rings" waspresented by Wade Plafcan on Dec 3, 2020 within the UNR Plant Talk series. Faculty, USDA personnel, graduate and undergraduate students regularly attend these seminars. A field trip was organized and taught by Prof. Tamzen Stringham for the Rangeland Restoration Ecology (REM 498) class taught in fall 2021. This trip involved visiting a mahogany plot and discussing project goals and activities. An outdoor lecture and evening slideshow was organized and presented by Prof. Tamzen Stringham for the Riparian Management and Restoration class (REM 499) during the fall 2020 semester. What do you plan to do during the next reporting period to accomplish the goals? The two new plots that have been treated at the study areawill be used to test if mahogany stands overtopped by pinyon are indeed responding favorably, once releasedfrom competition with pinyon, regardless of site differences. More data onbrowsing of mahogany by wildlife will becollected to further investigate the results obtained to date. Additional wood samples taken from the mahogany sections currently available will be sent to theW.M. Keck Carbon Cycle Accelerator Mass Spectrometry (AMS) facility at University of California, Irvine. Radiocarbon dating results are expected before the end of the project. Tree-ring dating of single-leaf pinyon will be completed to examine its dendroclimatic response. At least one presentation will be made at a professional meeting to reach our target audience.

Impacts
What was accomplished under these goals? Vegetation Analysis The following measurements were taken on 167 mahogany trees within 4 vegetation plots: mahogany diameter at root crown, height, canopy area, live crown length, percent dead canopy, crown light exposure. Trees were labeled with aluminum tags to allow for repeated measurements and future inspection. The following data on understory vegetation were collected in 4 plots: density, line point intercept for species composition and cover, species richness, litter cover. Initial analysis ofvegetation data suggests that there are a greater number of seedlings and saplings in the treated plots, indicating that there is likely more mahogany recruitment once the trees are released from competition with single-leaf pinyon. Plot dataalso suggestthat adult mahogany trees have less canopy dieoff in treated plots, indicating that adult trees may be healthier when released from pinyon competition. Pinyon removal was completed on two plots in October 2020. One cutting treatment was performed to complete the mastication in Porter Canyon, another one took place alongthe road to Edwards Creek on a plot that will allow us to monitor vegetation change over time. We have been able to establish that mountain mahogany presence/absence changes over short distances within the Desatoya Mtns. For instance, there was abundant mahogany mixed with single-needle pinyon (but no juniper) in the Porter Canyon mastication area, but we came across no mountain mahogany in the nearby Stoker Canyon, where both single-needle pinyon and Utah juniper are the dominant species. This is likely due to an elevation limitation on curlleaf mountain mahogany. Wildlife Impact Analysis All 10 vegetation plots were measured for fecal matter density in order to understand what wildlife species utilize the plots even where automated game cameras may not be present or continuosly functioning. In 6 vegetation plots associated with automated game cameras, browse measurements were taken on 120 mahogany trees. Initial analysis of browse measurement data suggests that treated plots are browsed more than untreated plots. Data analysis thus far has revealed that only some of the metrics that were measuredcan produce a statistically significant result. Measuring leader length on mahogany trees had no statistical significance between treated and untreated plots. However, when comparing form class rating and leader use percentages, there was a statistical difference between plots. The 34 automated wildlife cameras recorded images during 3sampling intervals totaling about 18 months, as follows: 10/25/19-12/18/19,5/16/20-1/23/21,5/27/21-12/8/21. Game camera images confirm the presence of mule deer at all treated and control plots, during both summer and winter seasons. Carnivores including mountain lions, bobcats, and coyotes have been observed on game camera images throughout the study area. Tree-Ring Analysis Radiocarbon analysis of 29 wood samples collected from 7 stem sections that were collected from 3 mountain mahogany trees showed that growth rings did not match the 'bomb spike' of the early 1960s. A large number of locally absent rings, ranging from about 15 to about 30 or more was responsible for the mismatch. Initial comparisons between visual crossdating and C14-dating revealedan erratic and opportunisti growth pattern that may prevent developing any reliable correlation between stem size and age in mountain mahogany. 12 additional stem sections were collected in October 2020 from 6 mahogany trees. A total of 13 single-leaf pinyons were sampled in June 2021 to update the master tree-ring chronology for that species that was developed for the Desatoya Mtns. in the early 2000s. One of the sampled pinyons, which is located inside the treatment area, dates back to at least 1358 CE even though it is only 77 cm in dbh.

Publications

  • Type: Conference Papers and Presentations Status: Submitted Year Published: 2022 Citation: Lyons, A., Snyder, D., Gundlach, J., Stringham, T., Stewart, K. & Biondi, F (2022). Quantifying the Impact of Pinyon-Juniper Removal on Curl-Leaf Mountain Mahogany Stands and Potential Mule Deer Habitat. In 75TH ANNUAL SRM (Society for Range Management) MEETING; Albuquerque, New Mexico, USA.


Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Project efforts were able to reach land managers at the Bureau of Land Management, who were involved in providing permits for field sampling. Changes/Problems:A member of the project staff (Dr. Emanuele Ziaco) left UNR in spring 2020. His replacement was delayed because of the uncertainty generated by the impacts on the university, and on scientific research in general, from covid-19 restrictions. The position is currently being advertised as a temporary Research Technician, and the search should be completed by the end of the year. While there have yet been no changes to the project's objectives and/or goals, it is likely that final results and outcomes will be lower than originally expected. What opportunities for training and professional development has the project provided?Three graduate students (Hondo Brisbin, Jason Gundlach, Lucas Phipps) acquired field and laboratory experience in performing vegetation sampling andwildlife monitoring. One graduate student (Wade Plafcan) received training in tree-ring analysis and radiocarbon dating. Seven undergraduate students (Mattie Johns, Sarah Johnson, Alexa Lyons, Jackson Miller, Kegan Richards, William Richardson, Juliet Wallis) acquired experience and skills in field sampling and monitoring of vegetation and wildlife. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We plan to continue performing project activities as outlined in the project proposal. In particular, we expect to conduct the following activities: • Sampling of soils, measurements of vegetation, and their comparison with presence/absence of mahogany stems. • Complete the tree-ring analysis of mahogany sections and compare it with radiocarbon dating results from the W.M. Keck Carbon Cycle Accelerator Mass Spectrometry (AMS) facility at University of California, Irvine. • Compile information from wildlife cameras. • Hiring a laboratory technician to help with tree-ring analyses. • Continue advising a graduate research assistant (Wade Plafcan).

Impacts
What was accomplished under these goals? Vegetation Analysis 6 plots were established, each with 5 subplots, in the vicinity of the installed game cameras. Three plots were established in areas where pinyon and juniper were removed 5-10 years ago - these are called "treated plots". Three plots were established adjacent to these plots and are considered "control". 5 additional plots were established (one to be placed in 2021) to observe vegetation change over time in treatment/control plots. The following data were collected on curlleaf mountain mahogany: mahogany diameter at root crown, height, canopy area, live crown length, percent dead canopy, crown light exposure. Trees were labeled with aluminum tags for repeated measurements. In plots associated with game cameras, browse measurements were taken on mahogany trees. The following data were collected on understory vegetation: density, line point intercept for species composition and cover, species richness, litter cover All data are stored in an Access database and in Excel spreadsheets. Pinyon removal was completed on two plots in October 2020. One cutting treatment was done to complete the mastication in Porter Canyon, another was along the road to Edwards Creek on a new plot that will allow us to monitor vegetation change over time. Wildlife Camera Trapping 34 game cameras have been deployed in the study area.Two of the paired plots have 12 cameras deployed in total; six in each treated plot and six in each control plot.The smallest pair of plots, located in Dalton Canyon, has ten cameras deployed with five in each plot. Camera locations were randomly generated within these plots using 10m buffers between locations. Trail camera viewsheds were chosen subjectively in order to best acquire camera trapping success based upon immediate terrain and vegetation features. Game cameras were initially deployed in October 2019 and are maintained on landscape continuously, with the exception of the harshest winter months to protect equipment. Images are stored on Box cloud storage. Tree-ring Analysis A total of 7 cross-sections that were taken from 3 live mahogany stems during the previous reporting period were analyzed using dendrochronological methods. Preliminary crossdating was performed back to 1945, and all ring widths were measured to the nearest 0.001 mm. Because of the difficulty in identifying ring boundaries and of the lack of common year-to-year variability among samples, dates assigned to rings are preliminary and will be further evaluated based on results from radiocarbon dating. A total of 29 wood samples were collected from the 7 mahogany cross-sections for radiocarbon dating. The samples were obtained by micro-drilling around the rings that were preliminarily dated as 1955, 1962, 1964, 1966, and 1975. Then a few mg of wood were carefully plucked from those rings so that their 14C content could be compared with the expected "bomb spike" peak of the mid-1960s. The wood samples have been sent to the W.M. Keck Carbon Cycle Accelerator Mass Spectrometry (AMS) facility at University of California, Irvine. Radiocarbon dating results are expected before the end of the year. Sampling permits from the Bureau of Land Management were renewed until 3/23/2021. A total of 12 cross-sections were obtained from 6 additional stems in Porter Canyon.

Publications


    Progress 07/01/19 to 09/30/19

    Outputs
    Target Audience:Project efforts were able to reach land managers at the Bureau of Land Management, who were involved in providing permits for field sampling. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?A graduate student (Jason Gundlach) received field experience in selecting sites for wildlife monitoring. He also acquired experience in ordering, setting up, and installing automated cameras for wildlife monitoring. Two undergraduate students (Sarah Johnson, Jackson Miller) acquired experience and skills in field sampling and monitoring of vegetation and wildlife. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We plan to continue performing project activities as outlined in the project proposal. In particular, we expect to conduct the following activities: Sampling of soils, measurements of vegetation, and cutting of mahogany sections at 1-2 sites. Preparation of wood samples for radiocarbon dating, and shipment to an AMS-14C facility. Preliminary tree-ring analysis and development of age-dbh relationships. Preliminary analysis of information from wildlife cameras. Sampling and analysis of mule-deer fecal pellets. Recruit a graduate research assistant to begin in fall 2020.

    Impacts
    What was accomplished under these goals? 1. One 50x50 m vegetation plot was measured in the Porter mastication area prior to treatment. A total of 72 mountain mahogany trees were recorded, with 64 of them over 2 meters in height. A subsample of 15 mahogany trees was used to represent three height classes (0.3-1m, 1-2 m, and >2m), and were permanently marked for further monitoring. 2. A total of 9 cross sections were obtained from four mahogany trees (one was completely dead). Since every sampled tree was multi-stemmed, and care was taken in sampling only one of the live stems, no tree was killed during the sampling. 4. A total of 34 automated wildlife cameras were acquired and installed at three field sites (12+12+10). Within each site, an equal number of cameras was randomly positioned at a "treated" and an "untreated" area.

    Publications