Gretchen Smith

Regional assessment of ozone sensitive tree species using bioindicator plants.

Tropospheric ozone occurs at phytotoxic levels in the northeastern and mid-Atlantic regions of the United States. Quantifying possible regional-scale impacts of ambient ozone onforest tree species is difficult and is confounded by other factors, such as moisture and light, which influence the uptake of ozone by plants. Biomonitoring provides an approach to document direct foliar injury irrespective of direct measure ofozone uptake. We used bioindicator and field plot data from theUSDA Forest Service to identify tree species likely to exhibit regional-scale ozone impacts. Approximately 24% of sampled sweetgum (Liquidambar styraciflua), 15% of sampled loblollypine (Pinus taeda), and 12% of sampled black cherry (Prunus serotina) trees were in the highest risk category. Sweetgum and loblolly pine trees were at risk on the coastal plain of Maryland, Virginia and Delaware. Black cherry trees were at riskon the Allegheny Plateau (Pennsylvania), in the Allegheny Mountains (Pennsylvania, West Virginia, and Maryland) as well ascoastal plain areas of Maryland and Virginia. Our findings indicate a need for more in-depth study of actual impacts on growth and reproduction of these three species.

A National Ozone Biomonitoring Program – Results from Field Surveys of Ozone Sensitive Plants in Northeastern Forests (1994–2000)

Ozone biomonitoring is a detection and monitoring techniquethat involves documenting ozone-induced visible injury toknown ozone-sensitive species under conditions of ambientexposure. The USDA Forest Service administers a long-term,nationwide ozone biomonitoring program to address public andscientific concerns about ozone impacts on forest health. Asystematic grid is used as the basis for biomonitoring sitelocations. At each site, trained field crews evaluate amaximum of thirty plants of up to six species and record the amount and severity of leaf-injury on individualplants. Injury from ozone was found more often on biomonitoring sites in the eastern Unites States than in theinterior or west-coast areas. Further results from thenortheast reveal that in any year, there is a higherpercentage of ozone-injured plants with more severe symptomsin areas with relatively high ozone concentrations than inareas with relatively low ozone. In very dry years (e.g.,1999) the percentage of injured plants and injury severityestimates are both sharply reduced even though ambient ozoneexposures are high. These findings demonstrate thatbiomonitoring data provide meaningful evidence of when highozone concentrations during the growing season have biologicalsignificance. Any assessment of ozone stress in the forestenvironment must include both biomonitoring (i.e., plantresponse) and air quality data to be complete.

Status and future of the forest health indicators program of the USA

For two decades, the US Department of Agriculture, Forest Service, has been charged with implementing a nationwide field-based forest health monitoring effort. Given its extensive nature, the monitoring program has been gradually implemented across forest health indicators and inventoried states. Currently, the Forest Service’s Forest Inventory and Analysis program has initiated forest health inventories in all states, and most forest health indicators are being documented in terms of sampling protocols, data management structures, and estimation procedures. Field data from most sample years and indicators are available on-line with numerous analytical examples published both internally and externally. This investment in national forest health monitoring has begun to yield dividends by allowing evaluation of state/regional forest health issues (e.g., pollution and invasive pests) and contributing substantially to national/international reporting efforts (e.g., National Report on Sustainability and US EPA Annual Greenhouse Gas Estimates). With the emerging threat of climate change, full national implementation and remeasurement of a forest health inventory should allow for more robust assessment of forest communities that are undergoing unprecedented changes, aiding future land management and policy decisions.

The Forest Inventory and Analysis Database Version 4.0: Database Description and Users Manual for Phase 3

Describes the structure of the Forest Inventory and Analysis Database (FIADB) 4.0 for phase 3 indicators. The FIADB structure provides a consistent framework for storing forest health monitoring data across all ownerships for the entire United States. These data are available to the public.

Ambient ozone injury to forest plants in Northeast and North Central USA: 16 years of biomonitoring

The US Forest Service administers a long-term, nationwide ozone biomonitoring program in partnership with other state and federal agencies to address national concerns about ozone impacts on forest health. Biomonitoring surveys begun in 1994 in the East and 1998 in the West provide important regional information on ozone air quality and a field-based record of ozone injury unavailable from any other data source. Surveys in the Northeast and North Central subregions cover 450 field sites in 24 states where ozone-sensitive plants are evaluated for ozone-induced foliar injury every year. Sites are typically large, undisturbed openings (>3 acres in size) close to forested areas where >3 bioindicator species are available for evaluation. Over the 16-year sampling period, injury indices have fluctuated annually in response to seasonal ozone concentrations and site moisture conditions. Sites with and without injury occur at all ozone exposures but when ambient concentrations are relatively low, the percentage of uninjured sites is much greater than the percentage of injured sites; and regardless of ozone exposure, when drought conditions prevail, the percentage of uninjured sites is much greater than the percentage of injured sites. Results indicate a declining trend in foliar injury especially after 2002 when peak ozone concentrations declined across the entire region.

Ozone bioindicators and forest health: a guide to the evaluation, analysis, and interpretation of the ozone injury data in the Forest Inventory and Analysis Program

In 1994, the Forest Inventory and Analysis (FIA) and Forest Health Monitoring programs of the U.S. Forest Service implemented a national ozone (O3) biomonitoring program designed to address specific questions about the area and percent of forest land subject to levels of O3 pollution that may negatively affect the forest ecosystem. This is the first and only nationally consistent effort to monitor O3 stress on the forests of the United States. This report provides background information on O3 and its effects on trees and ecosystems, and describes the rationale behind using sensitive bioindicator plants to detect O3 stress and assess the risk of probable O3 impact. Also included are a description of field methods, analytic techniques, estimation procedures, and how to access, use and interpret the ozone bioindicator attributes and data outputs such as the national ozone risk map.

Modelling ozone injury to U.S. forests

Lower atmospheric ozone, a gaseous air pollutant, is toxic to many plants and threatens the health of forests across the United States. In the 1990s, the USDA Forest Service began a monitoring program to assess status and trends with respect to the presence of phytotoxic concentrations of ozone in our nation’s forests. Ozone detection is based on the foliar (leaf) injury response of ozone-sensitive bioindicator species; a response that is conditioned primarily by the levels of ozone in the air and moisture in the soil. One goal of the program is to use the injury data in conjunction with ozone exposure and plant/soil moisture indices to develop a quantitative assessment of the effects of ozone pollution on plant life across the country. Preliminary work found that a logistic regression model was inadequate to describe the relationship between ozone injury and the environmental factors. Hoping for a better fit, we applied a generalized additive model. We refined the model by using different categorization methods for foliar injury and by incorporating different geographic and ecological factors. Finally, we concluded that our refined model, when compared to the logistic model, explains the data better and provides a better description of the relationship of interest.

Mineral element composition of declining and healthy stands of red spruce in western Massachusetts

Abstract Concentrations of N, P, K, Ca, Mg, and Mn were determined in one‐, two‐, and five‐year‐old needles from upper and lower crowns of declining and healthy red spruce (Picea rubens Sarg.) to assess nutritional deficiencies as causes of severe defoliation in upper‐elevation forests in western Massachusetts. Concentrations of N and K did not differ between stands or positions in crowns but decreased with leaf age. In declining stands, mean Ca concentrations were the same in the upper and lower crowns (3.2 mg g‐1), whereas in healthy stands, Ca was higher in the lower crown (4.8 mg g‐1) than in the upper crown (3.9 mg g‐1). Five‐year‐old needles of healthy trees had higher Ca than those of declining trees (6.0 and 3.8 mg g‐1, respectively). Mean concentrations of P and Mg in declining trees were 0.9 and 0.5 mg g‐1, respectively, with each element being at threshold levels of sufficiency. Mean concentrations of P and Mg, respectively, were 0.3 mg g‐1 and 0.2 mg g‐1 lower in needles of declining trees tha...

Towards an air pollution effects monitoring system for the Sierra Nevada

Abstract Over the next ten to twenty years, Californias population is projected to increase, particularly in air basins upwind of the Sierra Nevada mountain range (i.e., San Francisco Bay Area, Sacramento and San Joaquin Valleys). Related trends in ozone (O 3 ) concentrations are a matter of special concern, due to a long history of O 3 injury to sensitive pines in national forests of the Sierra Nevada. While the USDA Forest Service has limited authority over polluted air masses crossing into forest boundaries, monitoring results can be used in a collaborative effort with state and federal environmental protection agencies to protect resources at risk. One such effort was initiated under the Sierra Nevada Framework for Conservation and Collaboration. An ambient O 3 concentrations and O 3 effects monitoring system is under development that will integrate previous and current monitoring efforts across agencies, and will track pollutant concentrations and effects over the entire bioregion.