Sierra Nevada Science Symposium 2002: Science for Management and Conservation
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POSTER SESSION: Forest Ecosystems
Abstracts for each of the posters can be viewed below by clicking on the title of the poster.



Soil Moisture and Tree Seedling Distributions in a Mature Mixed-Conifer Forest
Andrew Gray, PNW Research Station, 3200 SW Jefferson Way, Corvallis, OR 97333; ph: 541-750-7252, email: agray01@fs.fed.us. Harold Zald, PNW Research Station, 3200 SW Jefferson Way, Corvallis, OR 97333. Malcolm North, Sierra Nevada Research Center, 2121 2nd Ave., Suite 101A, Davis, CA 95616.


We examined the distribution and abundance of tree seedlings and soil moisture in relation to stand structure in an old-growth, Sierra Nevada mixed conifer forest. These were pre-treatment measurements for the forest restoration experiment at the Teakettle Experimental Forest. Tree seedlings found consisted of the following species in declining order of abundance: white fir (Abies concolor), incense cedar (Calocedrus decurrens), black oak (Quercus kelloggii), bitter cherry (Prunus emarginata), red fir (Abies magnifica), sugar pine (Pinus lambertiana), and Jeffrey pine (Pinus jeffreyi). Most species declined in abundance from closed-canopy areas to open areas to whitethorn ceanothus (Ceanothus cordulatus) dominated areas. The exceptions were bitter cherry, which was most abundant in ceanothus patches, Jeffrey pine, which was most abundant in open areas, and black oak, which was most abundant in bedrock-dominated areas. For most tree species, areas with seedlings tended to have greater soil moisture then areas without seedlings. Soil moisture declined steadily in the top 45 cm of soil during the growing season. Volumetric moisture values soon after snowmelt (mid-May) averaged 18% (range 12-33%), and declined to 14% (6-47%) by early July and 10% (5-28%) by October. The high variability in moisture was associated with differences in topography and soil depth, and will probably be important in determining the location and speed of vegetation response to disturbance.




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Edge Effects in Mixed Conifer Group Selection Openings: Tree Height Response to Resource Gradients
Robert York* and John Battles, Department of Environmental Science Policy and Management, University of California, 151 Hilgard Hall; *ph: 510-643-2450; *email: ryork@nature.berkeley.edu. Robert Heald, Blodgett Forest Research Station, Center for Forestry, University of California, 4501 Blodgett Forest Road, Georgetown, CA 95634


The group selection method of regenerating forests has been proposed as an alternative to clearcutting that potentially maintains economic viability while preserving ecosystem integrity. However, questions remain about the appropriate size of the openings and the subsequent effect of edges on tree performance, as well as about what resources are limiting seedling growth within edge zones. To address these uncertainties for Sierran mixed conifer forests, replicated circular openings ranging in size from 0.1 ha to 1 ha were cleared in 1996 at the Blodgett Forest Research Station and planted with seedlings of six native species. After three years of growth, heights of all trees were measured and analyzed according to species, opening size, and location within the opening. To determine the cause of the edge influence on height, we measured differences along north-south transects in extension growth, pre-dawn water potential, and light availability for three species of trees: giant sequoia (Sequoiadendron giganteum), ponderosa pine (Pinus ponderosa), and Douglas-fir (Ptseudotsuga menziesii var. menziesii).

The sequence of mean height from tallest to shortest based on species was: giant sequoia > incense cedar > Douglas-fir > ponderosa pine > white fir > sugar pine. For all species combined, a ten-fold increase in the area of the opening corresponded to a 34% increase in mean height. Trees were tallest on average in the north rows and shortest in the south rows. There was no difference in height between trees in the east and west rows. As expected, resource availability was greatest near the center and least near the edges with north edges receiving significantly more light than southern edges. In general, observed edge effects on sapling height growth were correlated with light and water supply. However there were important differences between species in the nature of the co-limitation. Giant sequoia growth was most sensitive to light and water availability. Together they explained more than 47% of the observed variation in giant sequoia height. In contrast, only light was a significant predictor of ponderosa pine performance. Douglas-fir heights were significantly related to both light and water but there was more unexplained variability in the Douglas-fir model compared to the other species. These highly controlled experimental group openings provide a standard reference for silviculturalists using the group selection method of regeneration.




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Soil Nutrient Pools and Fluxes within a Mixed-Conifer Forest: Implications for Ecological Restoration
Heather E. Erickson, School of Science and Technology, Universidad Metropolitana, San Juan, Puerto Rico; email: um_herickson@suagm.edu. Dale Johnson, Department of Environmental and Resource Science, University of Nevada, Reno, Nevada. Patricia Soto, School of Science and Technology, Universidad Metropolitana, San Juan, Puerto Rico. Carolyn Hunsaker, USFS, Pacific Southwest Research Station, Fresno, California.


Forest burning and thinning have obvious effects aboveground, yet effects on soil nutrient pools and fluxes are less apparent. As part of a large-scale forest restoration experiment, we assessed baseline differences in soil resources for three dominant patch types within a mixed-conifer forest. Organic and surface mineral horizon soils (0 - 15 cm) were collected from fifty-four patches (18 each for closed canopy, open canopy, and Ceanothus) and used to determine inorganic nitrogen (N), net N mineralization using laboratory incubations, and total pools of carbon (C) and N. In-situ fluxes of inorganic N and ortho-phosphorus were also measured using resin lysimeters. For over two years, Ceanothus showed greater nitrate-N and net N mineralization in organic horizons and ammonium-N and net N mineralization in mineral horizons than other patch types. In contrast, N and P fluxes measured by resin lysimeters did not differ significantly among the patches. In organic horizons N pools were equally high in closed canopy and Ceanothus while C pools were greater under closed canopy. In mineral soils N and C pools were greater under Ceanothus and open canopy than under closed canopy. Thus, restoration activities will likely affect the patches uniquely.




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Mapping Sierra Nevada Vegetation Structure with Radar, Lidar, and Multispectral Fusion of Remote Sensors
Jo Ann Fites-Kaufman, USDA Forest Service, Adaptive Management Services Enterprise Team, Tahoe National Forest, 631 Coyote Street, Nevada City, CA 95959, email: jfites@fs.fed.us. Carolyn Hunsaker,USDA Forest Service, Pacific Southwest Research Station. Peter Hyde, University of Maryland. Ralph Dubaya, University of Maryland. Leland Pierce, University of Michigan. Wayne Walker, University of Michigan. Birgit Peterson, University of Maryland. Bryan Blair, University of Maryland. Holly Hyde, USDA Forest Service, Adaptive Management Services Enterprise Team. Michelle Hofton, University of Maryland.


At the present time, the different subregions of the Sierra Nevada are mapped during different years and with different methodologies, contributing to inconsistent assessments of wildlife habitat, old growth forest conditions, and fuel mapping and fire behavior analysis. The objective of this project is to develop a reliable, cost-effective process to evaluate and monitor wildlife habitat, old growth forests, fuels, and potential fire behavior. Structural attributes evaluated were: large tree density (for old growth), tree height, crown base height and crown bulk density (for crown fuels), and canopy cover and layering (for wildlife habitat). Remote sensors included the radar, lidar, and Landsat TM. Lidar and radar have been successful in mapping biomass, tree heights, canopy cover, large tree density and canopy layering in other parts of the country but have not been tested in the diverse forests of the Sierra Nevada. Results to date show that lidar can map canopy heights well in the Sierra Nevada (R2=0.75, SE 8.2 m), with increasing accuracy away from plot edges (R2=0.93, SE 4.8 m). Canopy cover was estimated within 8% of measured values (R2=0.81). Biomass was also estimated successfully, with a RMSD of 251 Mg/ha (R2=0.83). Work with radar and fusion are underway.




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Hydrologic Characterization and Implications of Forest Soil Disturbance at a Plot Scale: A Case Study in the California Sierra Nevada Mixed Conifer Zone
Lucas W. Paz, Ph.D., 1900 Powell St. 12th Floor, Emeryville, CA 94608; ph: (510) 596-9664; email: lucas.paz@lfr.com


A series of physical and chemical environmental parameters were monitored to describe soil hydrology and plant characteristics on an artificially disturbed forest soil in the western Sierra Nevada Mountains, California. USFS Long Term Soil Productivity (LTSP) Research Program disturbance treatment plots were assessed to characterize the impacts of forest removal, soil compaction and the removal of organic residue on soil moisture characteristics and related physiological processes related to soil water uptake and site hydrology. The primary investigation (1997-1999) assessed a broad range of soil parameters as a basis to determine the relative influence of organic residue and soil compaction on soil permeability and moisture capacity. In-situ volumetric soil moisture content was monitored throughout the 1998-growing season and soil moisture characteristics were developed in the laboratory from soil water retention data. The results demonstrate how soil disturbance typified by compaction and organic matter removal can decisively alter the seasonal soil moisture regime and plant available water. Significant changes in soil porosity and the depth of organic residue were found to directly affect infiltration potential, soil water content, soil water potential and availability, soil temperature, soil aeration and leaf water potential. A soil moisture balance for the 5 soil disturbance treatments REF(control/reference), OM-0 C-0(stem removal only), OM-2 C-0(whole tree and forest floor removal), OM-0 C-2(stem removal and soil compaction), and OM-2 C-2(whole tree removal, forest floor removal and soil compaction) was modeled using available soil moisture parameters established during the 1998 sampling period. Soil disturbance typified by a loss in porosity reduced plant available soil moisture late in the growing season and resulted in reduced potential for translocation of moisture to deeper subsurface zones.




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Throughfall Deposition of Nitrogen in the Sierra Nevada as Determined by Ion Exchange Resin Columns
Mark Fenn, Pacific Southwest Research Station, USDA Forest Service, 4955 Canyon Crest Drive, Riverside, CA 92507; ph: (909)680-1565; email: mfenn@fs.fed.us


Nitrogen (N) deposition rates are high in some areas of California as a result of emissions from motor vehicles and agricultural activities. Total N deposition inputs are not known for most Sierra Nevada sites, largely due to the cost and technical difficulties of measuring the array of physical and chemical forms of nitrogenous pollutants. Recent studies demonstrate that monitoring throughfall N deposition using "passive" throughfall collectors is a viable method for estimating N deposition inputs at a larger number of sites than is practical with other techniques. This methodology is based on ion exchange resin columns that adsorb inorganic N ions from throughfall or bulk deposition solutions.

In this paper, data is presented on throughfall deposition measured with passive collectors at 11 sites along a north-south transect in the Sierra Nevada. The importance of NHx emissions from agriculture in the Central Valley is evident from these data. The usefulness of this modified throughfall collection method will be evaluated and the potential ecological impacts of N deposition will be discussed. We propose that ion exchange throughfall collectors can be used to determine the N deposition thresholds at which key ecological effects, including water quality impacts, may occur in the Sierra Nevada.




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California Land Cover Mapping And Monitoring: Creating and Maintaining Systematic and Accurate Land Cover Maps
Chris S. Fischer, California Department of Forestry and Fire Protection, 1920 20th Street, Sacramento, CA 95814; ph: (916) 227-2652; email: Chris.Fischer@fire.ca.gov. Mark Rosenberg, California Department of Forestry and Fire Protection, 1920 20th Street, Sacramento, CA 95814. Lisa M. Levien and Brian D. Schwind, U.S.D.A. Forest Service, 1920 20th Street, Sacramento, CA 95814.


An accurate depiction of the spatial distribution of habitat types within California is required for a variety of functions. The relative extent of vegetation or habitat types in different ownerships, watersheds, and counties has major implications for policies and strategies that are often ownership specific. To conduct the "Forest and Range 2002 Assessment", we combined vegetation extent, composition and structure information from numerous sources into a format compatible for use within a Geographic Information System (GIS) that allows statistical analysis as well as numerous spatial modeling efforts to address timber, range, fire, development impacts, and wildlife habitat issues.

The California Land Cover Mapping and Monitoring Program (LCMMP), a cooperative program between the USDA Forest Service and the California Department of Forestry and Fire Protection, creates seamless data from Landsat Thematic Mapper (TM) satellite imagery. Vegetation data establish existing conditions from which impacts of changes over time are assessed and provide mid-scale vegetation information. These data are captured using automated, systematic procedures that can efficiently and consistently map large areas at a low cost. Regionally, monitoring can identify patterns and critical causes of change. Locally, monitoring can assess county land use policies, identify areas of insects or disease problems, or assess the extent and impact of timber harvest in a watershed.




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The Response of Cheatgrass (Bromus tectorum L.) and Native Flora to Ecological Manipulations in the Yellow Pine-Mixed Conifer Forest
Thomas W. McGinnis, U.S. Geological Survey, Biological Resources Discipline, Western Ecological Research Center, Sequoia-Kings Canyon National Park, Three Rivers, CA 93271, ph: (559) 565-4262, email: tmcginnis@usgs.gov. Jon E. Keeley, U.S. Geological Survey, Biological Resources Discipline, Western Ecological Research Center, Sequoia-Kings Canyon National Park, Three Rivers, CA 93271. Matt Brooks, U.S. Geological Survey, Biological Resources Discipline, Western Ecological Research Center, Las Vegas Field Station, Las Vegas, NV 89119. Robert Sanford, Department of Biological Sciences, University of Denver, Denver, CO 80208. Jayne Belnap, U.S. Geological Survey, Biological Resources Discipline, Forest and Rangeland Ecosystem Science Center, Moab, UT 84532.


Manifest Destiny opened up the west to settlers and their weeds, and one of the most persistent weeds in western rangelands is cheatgrass. Burned areas are quickly colonized by cheatgrass as isolated satellite populations spread their seeds into these newly disturbed lands. Although the areas west of the Sierra Nevada Mountains have long been converted to non-native annual grasses, such as Bromus and Avena, and cheatgrass commonly invades east of these mountains, in the Great Basin, the forests in between were once thought to be immune to annual grass invasions. Although cheatgrass has been known to exist along roads and trails in these mountains for some time, widespread invasions in the yellow pine forest were unheard of in the past. Today, large expanses of these forests are becoming carpeted by cheatgrass. One such area of widespread invasion is the Cedar Grove area of Kings Canyon National Park, where our study takes place.

Because we do not know what disturbance factors trigger cheatgrass invasions in these forests, we do not know how to prevent its invasion. In 408 randomly assigned 5x5 m test plots (six replicate sites), we are intensifying several disturbance factors in order to determine how each affects cheatgrass and native plant cover. Plots either remain unburned, or are burned in one of three burning seasons. Before and after each burning season, soils are tested to see how temperatures affect soil nutrients. Temperatures are monitored above and belowground using six thermocouples per plot. Plots are assigned one of the following manipulations: no addition, pine litter addition, 50% shade, added or reduced nitrogen, added or reduced phosphorous, cheatgrass seed addition, or native seed addition. Although no manipulation following the low-intensity Fall 2001 burns resulted in the elimination of cheatgrass, it is expected (after observing the unmanipulated forest surrounding these plots) that the addition of 5 cm of pine needles, a treatment added in 2002, will eradicate cheatgrass. Other plant cover changes will be discussed relative to each disturbance factor.




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Tree Growth and Death in the Sierra Nevada
Nathan L. Stephenson* and Phillip J. van Mantgem, USGS Western Ecological Research Center, Sequoia and Kings Canyon Field Station, Three Rivers, CA 93271; ph: (559) 565-3176; *email: nstephenson@usgs.gov. Peggy E. Moore, USGS, Western Ecological Research Center, Yosemite Field Station, El Portal, CA 95318.


Models suggest that forest characteristics are profoundly affected by the nature of the relationship between tree growth rate and probability of death. Yet little is known about the relationship, or how environmental changes might affect it. In particular, "gap" models of forest dynamics rely on two untested assumptions: (1) causes of tree death fall into two groups: those independent of and those dependent on growth rate, and (2) the only way environmental changes affect probability of death is indirectly, by altering growth rate. We examined these assumptions by tracking the growth and survival of 10,691 trees, recorded 775 deaths by cause. Contrary to assumptions, no cause of death was independent of growth rate. However, the strength of the relationship between growth and death differed significantly among causes. Additionally, white pine blister rust was found to increase probability of death in Pinus lambertiana growing at all rates, demonstrating that changes in probability of death can be either growth-mediated, as assumed in gap models, or direct, resulting from a change in the nature of the relationship between growth rate and probability of death. We discuss implications of our findings for understanding and predicting the potential effects of environmental changes on tree mortality.




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Continuous Forest Inventory in California: New Design Provides Rich and Timely Data for a Variety of Applications
Karen Waddell* and Sally Campbell, Pacific Northwest Research Station, Forest Inventory and Analysis program, PO Box 3890, Portland, OR, 97208; ph: (503) 808-2046 or (503) 808-2034; *email: kwaddell@fs.fed.us


The Pacific Northwest Research Station's Forest Inventory and Analysis (PNW-FIA) program inventories public and private forestlands in California, Oregon, Washington, Alaska, and the Pacific Islands. In the last few years, PNW-FIA has implemented a new nationally-consistent 4-point design across all ownerships. Inventory plots are now sampled on an annual basis instead of the traditional 10-year cycle. PNW-FIA databases contain a diverse array of unbiased estimates for many attributes of California's forest ecosystems. A variety of summary reports, analyses, and research studies are actively being worked on by PNW-FIA staff and collaborators, and many projects either focus on or are relevant to forests in the Sierras. Examples of ongoing projects include a study of California's hardwoods, sudden oak death, fuel treatment feasibility and acceptance, and an update of forestland statistics. This poster will highlight details of the new inventory design, summarize the type of data being collected and calculated, and describe some of the projects that use either current or past inventory information.




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A Contrast in Vital Rates: Life Table Projections for Abies concolor and Pinus lambertiana in a Sierran Mixed Conifer Forest
John J. Battles* and Frieder G. Schurr, Ecosystem Sciences Division,University of California Berkeley, 151 Hilgard Hall, Berkeley CA 94720; ph: (510) 643-0684, *email: jbattles@nature.berkeley.edu; Center for Forestry, University of California, Berkeley, 4501 Blodgett Forest Road, Georgetown, CA 95634; ph: (530) 333-4475.


We examined the demography of Abies concolor (Abco) and Pinus lambertiana (Pila) in a mature mixed conifer forest in the Sierra Nevada. We constructed size-classified matrix models and then applied elasticity analysis to determine what vital rates (survival, growth, and fecundity) were the most important determinants of population change. Survival of canopy-sized Abco averaged 0.985/yr for the last 30 years. Fecundity (measured as the number of germinants produced) over the last 5 years averaged 154 germinants/canopy tree*year. The projected population growth rate for Abco was 1.007, indicative of a slowly growing population. In contrast, Pila was projected to decline with a growth rate equal to 0.985. Adult survival, particularly in the codominant size class, was much lower for Pila than Abco (0.939). Pila fecundity averaged less than 10 germinants/tree*year. Changes in the Pila population were extraordinarily sensitive to the survival rate of canopy trees (elasticity = 0.856). The Abco population was also dependent on adult survival (elasticity = 0.506) but understory tree survival was another important component (elasticity = 0.371). These projections support the contention that the Sierran conifer forests are communities currently ruled by non-equilibrium dynamics. Both fire suppression and an introduced pathogen contribute to the uncertain future of these forests.




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Characterizing Light Regime of Different Mature Forest Stand Structures
Rolf Gersonde* and Kevin L. O'Hara, ESPM-Forest Science Division, 145 Mulford Hall, University of California, Berkeley, CA 94720-3114; ph: (510) 643-2025, *email: gersonde@nature.berkeley.edu


Successful regeneration of mixed-conifer forests depends on conditions suitable for survival and growth of all desired species. The light regime under the forest canopy has a strong influence on the competitive interaction of the regenerating species and can be manipulated by the forest manager through density management of the overstory. Using the light model tRAYci we calculated the light transmission through canopies of different densities, overstory species, and spatial structure: seed tree, shelterwood, small group selection, and closed canopy. Average light intensity at the forest floor was lowest in the closed canopy stand (125 sqft/ac BA), followed by the shelterwood (75 sqft/ac BA), small group selection (0.25 acre opening), and was highest in the seed tree stand (17.4 sqft/ac BA). There was a significantly lower light intensity at the forest floor when the overstory was composed of white fir (Abies concolor) as compared to ponderosa pine (Pinus ponderosa). Variability of incident light in the transition zone increased with stand density. Variation in aspect caused a small but significant change (2.7%) in average light intensity at the forest floor. We present data that shows differences in the vertical profile of light transmission through the canopy. Light profiles in all stands showed a homogeneous light regime below the foliated crown space (dim light zone, 0-15m) and rapidly increasing light transmission in the transition zone (15-30m). Light intensity and the vertical position of the light gradient have consequences for the resource availability to understory trees. Characterizing the available light resources under various overstory structures can facilitate development of management guidelines for regeneration of mixed-conifer stands.




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Reconstruction of Historical Vegetation Distributions in the Sierra Nevada Using Government Land Office Survey Records
Holly Hyde* and Jo Ann Fites-Kaufman, USDA Forest Service, Adaptive Management Services Enterprise Team, Tahoe National Forest, 631 Coyote Street, Nevada City, CA 95959, *email: hhyde@fs.fed.us. Michael Barbour, University of California at Davis. Dave Weixelman, USDA Forest Service, Adaptive Management Services Enterprise Team, Tahoe National Forest, 631 Coyote Street, Nevada City, CA 95959.


Most reconstructions of historical vegetation in the Sierra Nevada have focused at the site scale. The objective of this study was to reconstruct patterns of tree species composition at the landscape scale. Specifically, we were interested in the historic relationships of composition with environmental gradients. We utilized general land office (GLO) survey records, which represent a systematic grid of points at section corners, collected in the late 1800's. At each section corner, data was recorded in a manner that resembles the point-center-quarter procedure. We examined GLO data across three elevational gradients in the central and southern Sierra Nevada, encompassing modern foothill, ponderosa pine, mixed conifer, and red fir forests. A community classification (TWINSPAN-based) resulted in 15 community types. Based on canonical correspondence analysis, elevation was the primary environmental influence (80% of variance), followed by topographic position, and aspect. At elevations <1000m, oak was dominant (78% frequency) but pine comprised 24% of the basal area. Pine species represented 60% and 49% of the total basal area in low elevation (1000-1500m) and mid-elevation (1500-2000) areas. At low elevations, oak shared dominance (37% frequency) with pines, while at mid-elevations white fir comprised 16% of the basal area and 26% of the stems.




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Edge Effects of Group Selection Harvest on an Old Growth Forest in the Sierra Nevada
Zachary E. Kayler, Lucas B. Fortini, and John J. Battles*, University of California, Berkeley, Department of Environmental Science, Policy and Management, 151 Hilgard Hall, Berkeley, CA 94720-3110; *email: jbattles@nature.berkeley.edu


We measured the potential edge effects associated with the presence of a group selection harvest on the northern border of an old-growth Sierran conifer forest. Across transects that spanned from the interior of the old-growth forest through the group selection opening, we quantified changes in resource availability (light, water, and seedbed) and plant composition (abundance, richness). We found a steep change in resource availability: Plots in old-growth forests, even ones on the edge of the group opening were shadier (8% vs 50% full sun), had more water in the top 20 cm of soil, and had less exposed mineral soil. These three environmental variables explained more than a third of the observed variation in species composition. Both parametric and non-parametric multivariate analyses confirmed that there were two distinct plant communities, old-growth and group selection, with no indication of an ecotonal community along the edge. Understory plant species richness normalized to a total area sampled of 0.25 ha was significantly greater in the group selection (59 species) than in the old-growth (42 species). Non-native plant species accounted for a similar proportion of total species richness in both community types (4%). Chimaphila umbellata was a reliable indicator species of old-growth forest conditions.




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A Comparison of Ectomycorrhizal Response to Group Selection Cutting on Two Mixed Conifer Species, Pseudotsuga menziesii and Pinus ponderosa
Anna L. Levin*, John J. Battles, and Thomas D. Bruns, Ecosystem Sciences Division, University of California Berkeley, 151 Hilgard Hall , Berkeley CA 94720, ph: (510) 643-0684, *email: alevin@nature.berkeley.edu


Group selection has been proposed as an alternative to clearcutting, but the impact on one crucial component of seedling health, ectomycorrhizal fungi (EMF), has not been examined. We planted seedlings of Pseudotsuga menziesii (Psme) and Pinus ponderosa (Pipo) along a gradient from intact forest to opening in 1 ha groups at Blodgett Forest in order to 1) determine whether EMF colonization rates and species richness decrease with increasing distance from forest edge, and 2) examine whether patterns in EMF communities differ between the two conifer hosts. We found a significant reduction in EMF colonization and richness with distance from the edge for Psme. Colonization rate for Psme seedlings in the forest was nearly 100% with 4.8 EMF species per seedling but decreased to an average of 58% colonization and 3.2 species per seedlings in the opening. In contrast, there was no edge-related differences in EMF colonization or richness for Pipo: the colonization rate was 90% with approximately 4 EMF species per seedlings regardless of distance from forest edge. The reduction in EMF colonization and richness found on Psme in the opening suggest that establishment problems observed for Psme may be related to the mychorrhizal status of seedlings in large clearcuts.




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Growth of conifers planted under a shelterwood
Robert C. Heald* and Jennifer K. Prentiss, Center for Forestry, University of California, Berkeley, 4501 Blodgett Forest Road, Georgetown, CA 95634; *ph: (530) 333-4475; *email: bheald@nature.berkeley.edu


This study compares the survival and growth of conifer seedlings planted in various forest floor conditions under a shelterwood. Planting is indicated when some desirable seed trees are not available, for example sugar pine Pinus lambertiana resistant (Rr) to white pine blister rust Cronartium ribicola.

At Blodgett Forest Research Station, a shelterwood harvest retained 12 seed trees per acre. Tractor pile site preparation left burned piles as far away from shelterwood trees as possible. These locations become the best potential growth sites and the least likely to be stocked by natural seed fall. Fifty burn piles were planted with Rr sugar pine, Douglas-fir Psuedotsuga menziesii, ponderosa pine Pinus ponderosa, giant sequoia Sequoidendron giganteum and incense-cedar Calocedrus decurrens in ash, burn pile edge, and adjacent unburned area

After five years diameter and height of each planted seedling were recorded. Shrub species, percent cover, and height were measured on mil acre plot at each planted tree.

Average diameter and height of both sequoia and ponderosa were larger than that of sugar pine, cedar and fir. Shrubs grew more vigorously along the edge of the burned piles than in either ash or mineral soil, while trees grew faster when planted in ash.




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Sequoia Pruning Timing Study
Robert C. Heald* and Wm. David Rambeau, Center for Forestry, University of California, Berkeley, 4501 Blodgett Forest Road, Georgetown, CA 95634; *ph: (530) 333-4475; *email: bheald@nature.berkeley.edu


Young growth Giant Sequoia (Sequoiadendron giganteum) has potential to produce high value clear redwood products but exhibits virtually no self-pruning. Average branch diameters at age10 range from one to three cm as spacing increases from two meters to six meters. Thus, while planting density affects stem diameter and height, branch sizes remain well within the range that can easily be pruned by standard tools.

Little is known about the effects of pruning Giant Sequoia on growth, epicormic branching, heartwood formation and stem taper. This study was located in an existing sequoia density study at Blodgett Forest Research Station. Sequoias were pruned over a wide range of tree sizes and pruning intensities throughout a calendar year.

Measurements of 500 pruned and control trees included total tree height, stem diameter at several heights, existing epicormics, heartwood, branch recession, crown radius and branch diameters.

After pruning, Sequoia produce epicormic branches only at pruned branch collars. Sequoia pruned from October through May frequently develop epicormic branches. These sprouts first appear in conjunction with new leaf development the following June. Sequoias pruned June through September rarely develop epicormic branches. Frequency, quantity, and length of epicormic branches produced increase as pruning intensity increases.




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Mixed Conifer Plantation Growth
Robert C. Heald* and Nadia Hamey, Center for Forestry, University of California, Berkeley, 4501 Blodgett Forest Road, Georgetown, CA 95634; *ph: (530) 333-4475; *email: bheald@nature.berkeley.edu


Although there is little information available, many speculate greater wood productivity, increased visual quality, and wildlife species diversity from mixed-species plantations than single species plantings. This study examined a variety of cultural treatments in native mixed-species plantations established at Blodgett Forest Research Station.

For site preparation, was all woody material other than sawlogs were masticated and left in place following harvest. The sites were planted in April 1992 with an equal mix of pinus ponderosa, pinus lambertiana, calocedrus decurrens, abies concolor, pseudotsuga menziesii, and sequoiadendron giganteum on 2.5 meter square spacing. Harvested quercus kellogii stumps sprouted vigorously the same spring. In a random block design, six replications each of hand weeding, herbicide, and a no treatment control were applied in the second growing season. An additional eighteen similar treatment areas were exposed to grazing by range cattle. All treatments were thinned after the fifth year measurement to a residual density averaging 800 trees per hectare. Seasonal range cattle grazing (and the exclosures) continued throughout the study.

After ten years, tree heights and diameters varied significantly by species, treatment type, and total shrub cover. Combined grazing and weeding or grazing and herbicide plots developed the least shrub cover and largest trees.




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The Effects of Planting Density on Early Growth of Giant Sequoia (Sequoidenderon giganteum)
Robert C. Heald, Center for Forestry, University of California, Berkeley, 4501 Blodgett Forest Road, Georgetown, CA 95634; ph: (530) 333-4475; email: bheald@nature.berkeley.edu


This study measured 2,086 giant sequoia seedlings planted at spacings of seven to twenty feet. Giant sequoia shows remarkably early and extensive effects of competition. Spacing substantially affects early height growth of sequoia. By ten years, trees at wide spacing distance were showing 60% wider annual diameter growth and 50% higher annual height growth than trees at one half each respective spacing.

During the 9th and 10th growing seasons 27 trees were carefully measured every two weeks from April through October. Total season height and diameter growth generally increased with increasing spacing. Trees at wide spacings added about 1 inch in diameter and 2.6ft. in height, about 40% more growth than trees at half their respective spacings.

One explanation for the unusual response is that both height and diameter growth are limited by late growing season soil moisture depletion. Sequoias at all spacings had observable diameter growth by mid May. New leaf development, branch and height growth was not visible until mid June. Both height and diameter growth simultaneously ceased by September. This contrasts with the typical conifer early spring start and short duration of height growth followed by more gradual and longer duration secondary growth of the cambium.




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The Kings River Project: Small Stream Ecosystem Variability and Response to Fire
Carolyn Hunsaker and Sean Eagan, USDA Forest Service, Pacific Southwest Research Station, 2081 E. Sierra Avenue, Fresno CA 93710; ph: (559) 323-3211; email: chunsaker@fs.fed.us.


The quality of aquatic and riparian ecosystems is a function of their condition and the integrity of adjacent uplands in their watershed. While small streams make up a large proportion of the overall stream network, our knowledge of how they function is still limited. The Kings River Experimental Watershed was initiated in 2000 to quantify the variability in characteristics of small stream ecosystems and their associated watersheds. Forest managers want to know the effect of fire and fuel reduction treatments on the riparian and stream physical, chemical, and biological conditions.

Two mixed conifer sites are being developed at 1,700 to 2,400 m elevation. Data will be gathered for at least a 3-year reference period and then fire and harvesting treatments will be applied. After the treatments, data will be gathered for at least seven years. Each site will have a control watershed that receives no treatments, a watershed that is burned, a watershed that is harvested, and a watershed that is both burned and harvested. The watersheds range in size from 80 to 150 hectares; a size that can be consistently treated. Stream discharge, water chemistry, sediment loads, and invertebrate composition will be presented for water years 2000 and 2001.




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Seed Fall and Seedling Recruitment in Mixed Conifer Forests of the Sierra Nevada
Jon E. Keeley* and Philip van Mantgem, U.S. Geological Survey, Sequoia-Kings Canyon Field Station, Three Rivers, CA 93271; *ph: (559) 565-3170; *email: jon_keeley@usgs.gov


Regeneration is likely a sensitive indicator of global change perhaps evident in patterns of cone initiation, seed production, and seedling recruitment. This, however, is complicated by limited understanding of how current conditions control these parameters.
Recruitment strategies are poorly understood because of marked limitations in the temporal and spatial scale of study. The Sierra Nevada Global Change Project can contribute significantly because of its long-term focus across a broad elevational range from 1500 to 3000 m in the southern and central Sierra Nevada. Analysis along this gradient shows that elevation is an important predictor of conifer seedling density best illustrated by a simple exponential decay model. Elevational effects are only weakly evident in firs but prominent in pines. Not surprisingly in these largely undisturbed forests white fir (Abies concolor) dominates the recruitment and ponderosa pine (Pinus ponderosa) is barely represented. Incense cedar (Calocedrus decurrens) and sugar pine (P. lambertiana) patterns are broadly similar to white fir. Evidence of successful understory recruitment and establishment in the understory by sugar pine suggests limited fire dependence in this pine species. Although white fir is capable of successful recruitment in the understory of undisturbed forests it also recruits heavily into burned sites, suggesting the often-used term "a fire-intolerant species" may be inappropriate.




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The Effects of Logging and Prescribed Fire on Fecundity and Seed Dispersal of Sierran Conifers
Ruth Ann Kern, Department of Biology, California State University, Fresno, 2555 E. San Ramon Ave, M/S SB73, Fresno, CA 93740; ph: (559) 278-4075; email: rakern@csufresno.edu


Seed rain is being monitored in experimental forest treatment plots to investigate the effects of thinning and prescribed fire on seed production and seed dispersal distances of Sierra Nevada conifers. 18 1-ha forest research plots, established in the Teakettle Experimental Watershed, Sierra National Forest, have been manipulated in a 2 x 3 factorial design (fire or no fire; shelterwood thinning, CASPO thinning, or no thinning) with three replicates of each treatment. 25 seed 0.25 m2 seed traps have been installed on a 25 m grid in each or the 18 plots. Logging and fire treatments were completed in 2001 and seed traps were installed in early summer 2002. Data from this long-term study will be used to understand the individual and cumulative effects of the two methods of logging and of prescribed burning on seed production and seed dispersal distances of White Fir, Red Fir, Sugar Pine, Jeffrey Pine, and Incense Cedar.



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Differences in Stand Structure and Pattern of Sierra and Pacific Northwest Old-Growth Forests
Malcolm North, Sierra Nevada Research Center, Department of Environmental Horticulture, University of California, Davis, CA 95616; ph: (530) 754-7398; FAX: (530) 752-1819; email: mnorth@ucdavis.edu. Jiquan Chen, Landscape Ecology and Ecosystem Science, Bowman-Oddy Lab, MS 604, University of Toledo, Toledo, OH 43606; ph: (419) 530-2664, email: jiquan.chen@utoledo.edu. Brian Oakley, College of Forest Resources, Box 352100, University of Washington, Seattle, WA 98195; ph: (206) 543-7940, email: boakley@u.washington.edu


We compared species composition, structure, spatial pattern, light and soil moisture between two old-growth forests; closed canopy Pacific Northwest western hemlock/Douglas-fir at the Wind River Canopy Crane Facility and patchy Sierra Nevada mixed conifer at the Teakettle Experimental Forest. Teakettle has a lower basal area than Wind River, but it is concentrated in tree groups, 30-50 m in diameter, which have a similar basal area and higher density than Wind River. At Wind River large trees are regularly spaced from 0-15 m and shade-tolerant and intolerant species are 'repelled', while at Teakettle large trees are randomly distributed from 0-80 m and shade-tolerant and - intolerant species are 'attracted'. Average understory light is 15 times higher at Teakettle than Wind River. At Teakettle, there is no canopy stratification by shade tolerance, light in openings may inhibit horizontal stem pattern producing persistent gaps, suggesting mixed conifer may have a minimum canopy cover threshold for tree survival. Higher cover needed for tree establishment and growth may override stem repulsion produced by tree competition for growing resources. Traditional stand management which reduces canopy cover to release regeneration should be applied with caution in the southern Sierra Nevada.



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Influence of Light and Soil Moisture on Sierra Mixed-Conifer Understory Community
Malcolm North, Sierra Nevada Research Center, Davis, CA, 95616. Brian Oakley, College of Forest Resources, University of Washington, Seattle, WA 98195. Rob Figener, Department of Environmental Horticulture, University of California, Davis, CA 95616. Andrew Gray, Forest Inventory and Monitoring, PNW Research, Portland, OR 97208. Michael Barbour, Department of Environmental Horticulture, University of California, Davis, CA 95616.


Site conditions affecting herb and shrub dynamics in Sierra forests have not been well studied. In an old-growth, mixed-conifer forest, we examined the understory community and its distribution in relation to microsite conditions. We also measured canopy cover with three common field methods to compare their assessment of conditions influencing herb and shrub cover. Our objectives were to: 1) ordinate the understory plots to assess indirect environmental gradients influencing community structure; 2) test for significant differences in soil moisture, light, canopy cover, coarse woody debris or litter depth conditions between associations; 3) identify individual herbs and shrubs strongly correlated with specific site conditions; and 4) identify which measure of canopy cover is most strongly correlated with understory cover. Communities in the mixed conifer understory were strongly influenced by soil moisture, coarse woody debris, litter depth and understory light intensity. There appear to be threshold soil moisture and canopy cover levels, below which herbs are rare or absent. Spherical densiometer and 'moosehorn' canopy cover measurements are poor indicators of understory conditions because they do not account for canopy openings and sun angle. In the southern Sierra Nevada, hemispherical photographs are needed to predict understory dynamics in response to fire and thinning disturbances.



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The Effects of Fire on Soil Nitrogen and Frankia Associated with Patches of the Actinorhizal Shrub Ceanothus cordulatus
Brian B. Oakley, University of Washington, College of Forest Resources, Box 352100, Seattle, WA 98195. Malcolm P. North, Sierra Nevada Research Center, Department of Environmental Horticulture, University of California, Davis, CA 95616. Brian P. Hedlund and James T. Staley, University of Washington, Department of Microbiology, Box 357242, Seattle, WA 98195. Jerry F. Franklin, University of Washington, College of Forest Resources, Box 352100, Seattle, WA 98195.


The largest inputs of nitrogen occur via symbiotic N-fixation, yet N-fixing plants are usually limited to the early stages of post-disturbance succession. Sierra Nevada forests, however, are an interesting exception as N-fixing Ceanothus spp. can dominate the understory even in mature and old-growth forests - possibly due to fire maintaining an open canopy. We focused on 2 research objectives: 1) Are soil N levels associated with patches of Ceanothus significantly enriched relative to surrounding areas and if so, does this effect persist after fire? 2) Does fire reduce the number of Frankia in the soil or select for particular strains of Frankia?

We conducted a burn experiment to determine if soil beneath C. cordulatus patches represent N 'resource islands' and if any N enrichment persists after fire to potentially influence forest regeneration and spatial patterning. Ceanothus patches are enriched relative to other patch types in total and mineral N before fire, and this effect largely persists after fire. Vigorous resprouting (particularly in plots burned at low intensity) and lower C:N ratios in Ceanothus patches will likely continue this trend into the future. Fire appears to have little effect on Frankia and regional Frankia diversity is low but distinct strains can be found at the scale of major biogeographic divisions.




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Fire and Fuels Management, Landscape Dynamics, and Fish and Wildlife Resources: An Integrated Research Plan on the Plumas and Lassen National Forests
Peter Stine*, John Keane, and Malcolm North, USDA Forest Service, PSW Research Station, Davis, 2121 2nd Street, Suite A-101, Davis, CA 95616; *ph: (530) 759-1703; *email: pstine@fs.fed.us. Scott Stephens, Department of Environmental Science, Policy, and Management, U.C. Berkeley. Doug Kelt and Dirk Van Vuren, Department of Wildlife, Fish, and Conservation Biology, U.C. Davis. Michael Johnson, John Muir Institute for the Environment, U.C. Davis. Geoff Geupel and Mary Chase, Point Reyes Bird Observatory.


This research program entails an integrated series of studies intended to evaluate land management strategies designed to reduce wildland fire hazard, promote forest health and ecosystem stability and provide economic benefits across a typical managed forest landscape such as that found on the Plumas and Lassen National Forests. The research program is organized around four principal issues: 1) efficacy of selected combinations of defensible fuel profile zones (DFPZs) and area fuel treatments to reduce the extent and severity of wildland fires, 2) the effects of group selection as a silvicultural tool on various forest elements and conditions, 3) cumulative effect of management regimes on landscape dynamics such as forest structure, composition and succession across time and space, and 4) species-specific responses to landscape changes resulting from different forest management regimes. At the most basic level, the objective of the proposed research is to address, in a coordinated effort, an array of related ecological questions and thereby provide empirical data to inform future management decisions.

At this time we are focusing upon five "modules" of response variable modules. These include; 1) Vegetation, 2) Fire and Fuels, 3) Density, reproductive success and diet of California spotted owls, 4) Small mammal distribution, abundance, and habitat relations, and 5) Landbird distribution, abundance, and habitat relations. The critical interplay of space and time, particularly over larger, longer, and more diverse frames of reference than most ecological research has attempted in the past, is a major objective of this research program. We are interested in the integrated response of key variables across broad landscapes through relatively long periods of time. While some questions can be addressed by substituting space for time or by inductive reasoning from short term, small-scale studies to broader landscapes, other questions unavoidably require a long-term research commitment over large landscapes.




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The Kings River Project: Historic Stand Structures, Forest Processes, and Vegetation Manipulation
Carolyn Ballard* and Ramiro Rojas, USDA Forest Service, Sierra National Forest, P.O. Box 559, Prather, CA 93651; ph: (559) 855-5355, *email: cballard@fs.fed.us.


The Kings River Project is intended to create an experimental framework at a watershed scale to examine the response of an array of ecosystem elements to uneven-aged, small group selection and prescribed fire. Structural variation caused by timber harvest or mechanical thinning is designed to be fine grained, mimicking small-scale natural disturbances, such as those caused by a few acres of high-intensity crown fires within a matrix of frequent low-intensity fires. The systems initiated for the study minimize the use of forest zoning, emphasize multi-resource objective management on homogenous areas in a watershed, and utilize the uneven-aged management system to program vegetation manipulation. Group selection and silvicultural practices are used to mimic effects of frequent, low intensity fire; fuels treatments are concurrent with silvicultural activities and typical harvest practices followed by slash piling, mastication, and prescribed burning are utilized to create openings. Defensible fuel profile zones are used within the wildland urban intermix to aid wildfire supression. Prescribed fires, alone or in conjunction with silvicultural treatments, are being conducted to improve ecosystem condition and return fire to the forest as a natural disturbance process.

The Kings River Project defines desired forest conditions as those stand structures and processes found in the area in the 1850's. An investigation of historic forest structures and processes was conducted to determine the range of variability found within the Project's watersheds. A vision of the stand structure and processes was developed from historic photos, descriptions from trained observers from the early 1900s, literature from similar neighboring forests, data collected from the early 1900s, and examinations conducted within the Project area. This analysis determined that while stand structures were variable, there are generalizations that can be made based on forest type, aspect, and slope. Frequent low intensity fire resulted in uneven-aged structures across the ponderosa pine and mixed conifer types. High variability existed between and within stands. Understory fuel loading was low. Regeneration occurred episodically rather than continuously. Stand density was characterized by widely spaced crowns. Many forest stands within the project area were characterized by unoccupied growing space. In contrast, high crown density and infrequent fires characterized the true fir stands. Fire was often stand replacing along the transition from pine-dominated stands to fir-dominated stands. Forest exams for 1912 and 1917 found little evidence of insect mortality.




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The Kings River Project: Overview
Carolyn T. Hunsaker, USDA Forest Service, Pacific Southwest Research Station, 2081 E. Sierra Avenue, Fresno, CA 93710; ph: (559) 323-3211, email: chunsaker@fs.fed.us. Nancy Fleenor, USDA Forest Service, Sierra National Forest, P.O. Box 559, Prather, CA 93651; ph: (559) 855-5355, email: nfleenor@fs.fed.us.


The Kings River Project seeks to determine whether desired landscape conditions that create forest stand structures, which mimic historic forest conditions and processes, can sustain wildlife populations and stream ecosystems while providing forest products. This poster provides an introduction to the Kings River Project; companion posters provide details on the research studies and management issues being addressed by this adaptive management effort. The Sierra National Forest and the Pacific Southwest Research Station are working together on the design, implementation, and analyses for the Kings River Project. Since 1994 the Kings River Project has been implementing a management system of uneven-aged group selection and a program of prescribed fire within two adjacent watersheds comprising 150,000 acres. Current research studies include: stream ecosystems and watershed condition, demography of the California spotted owl, variations in the abundance and productivity of forest birds, occurrence and distribution of fishers, and long term soil productivity. The Project is examining the response of these ecosystem elements to timber harvest and prescribed fire.




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Inventory and Risk Assessment of Aspen on the Eagle Lake Ranger District, Lassen National Forest
Bobette E. Jones and Tom H. Rickman, Eagle Lake Ranger District, Lassen National Forest, 477-050 Eagle Lake Road, Susanville, CA, 96130; ph: (530) 257-4188; email: bobettejones@fs.fed.us.


An aspen (Populus tremuloides Michx.) inventory and risk assessment project is being conducted on the Eagle Lake Ranger District (ELRD), Lassen National Forest. This project was initiated due to observed declines in health and distribution of aspen stands on ELRD. Objectives of this project are to 1) produce a complete inventory of aspen on ELRD by 2003, and 2) provide stand-specific management recommendations and include these recommendations in NEPA documents that will allow the required restoration activities to take place. Each aspen stand is delineated using Global Positioning Systems (GPS), and assessed based on risk factors identified by Bartos and Campbell (1998). Management recommendations are based on observed stand conditions. To date, 312 stands totaling 592 hectares with a mean stand size of 1.9 hectares have been inventoried. Eighty-seven percent of the stands have received a High or Highest priority rating, indicating that aspen are at risk. Aspen is considered a keystone species, and aspen communities are critical for maintaining biodiversity in western landscapes. Loss of aspen can be attributed primarily to successional processes that occur in the absence of natural fire regimes and with excessive browsing. Continuation of these processes that have existed for the past 100-140 years on the ELRD will result in the eventual loss of most aspen stands. ELRD's extensive inventory and restoration efforts are an attempt to avoid this loss.




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Modeling Ozone Uptake in Ponderosa Pine Throughout the Sierra Nevada
Jeanne A. Panek,* Laurent Misson, and Allen H. Goldstein, Environmental Science, Policy and Management, 151 Hilgard Hall, University of California, Berkeley 94720, *office ph: (510) 642-9732, *email: jpanek@nature.berkeley.edu.


Tropospheric ozone is a pollutant which is responsible for forest injury worldwide. It is a strong oxidant which invades foliage through stomatal pores and impairs normal physiological function. In the Sierra Nevada, ozone concentrations can be unrelated to ozone uptake. Peak ozone concentrations occur in the late summer, but uptake is low due to stomatal closure in response to moisture stress. Thus, concentration-based indices of ozone exposure do not accurately reflect the ozone "seen" by plants. To estimate ozone uptake in ponderosa pine (the most ozone-sensitive Sierran conifer) throughout the Sierra Nevada, we first measured gas exchange/physiology directly at 4 sites along an ozone gradient for 3 growing seasons and one winter. From this we developed and validated a model, then used the model to estimate ozone flux (ozone concentration x canopy conductance to ozone) across the Sierra Nevada and through time. With this approach, we can begin to develop cause-effect relationships between ozone stress and forest injury in pine. The uptake-modeling method is being adopted across Europe to replace concentration-based indices. This is one of very few studies attempting to model ozone flux to forests in the US, and will contribute to improving monitoring of Sierra Nevada forest health in response to ozone pollution.




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