Linking linear programming and spatial simulation models to predict landscape effects of forest management alternatives

Forest management planners require analytical tools to assess the effects of alternative strategies on the sometimes disparate benefits from forests such as timber production and wildlife habitat. We assessed the spatial patterns of alternative management strategies by linking two models that were developed for different purposes. We used a linear programming model (Spectrum) to optimize timber harvest schedules, then a simulation model (HARVEST) to project those schedules in a spatially explicit way and produce maps from which the spatial pattern of habitat could be calculated. We demonstrated the power of this approach by evaluating alternative plans developed for a national forest plan revision in Wisconsin, USA. The amount of forest interior habitat was inversely related to the amount of timber cut, and increased under the alternatives compared to the current plan. The amount of edge habitat was positively related to the amount of timber cut, and increased under all alternatives. The amount of mature northern hardwood interior and edge habitat increased for all alternatives, but mature pine habitat area varied. Mature age classes of all forest types increased, and young classes decreased under all alternatives. The average size of patches (defined by age class) generally decreased. These results are consistent with the design goals of each of the alternatives, but reveal that the spatial differences among the alternatives are modest. These complementary models are valuable for quantifying and comparing the spatial effects of alternative management strategies.     

Landscape assessment of side channel plugs and associated cumulative side channel attrition across a large river floodplain

Determining the influences of anthropogenic perturbations on side channel dynamics in large rivers is important from both assessment and monitoring perspectives because side channels provide critical habitat to numerous aquatic species. Side channel extents are decreasing in large rivers worldwide. Although riprap and other linear structures have been shown to reduce side channel extents in large rivers, we hypothesized that small “anthropogenic plugs” (flow obstructions such as dikes or berms) across side channels modify whole-river geomorphology via accelerating side channel senescence. To test this hypothesis, we conducted a geospatial assessment, comparing digitized side channel areas from aerial photographs taken during the 1950s and 2001 along 512 km of the Yellowstone River floodplain. We identified longitudinal patterns of side channel recruitment (created/enlarged side channels) and side channel attrition (destroyed/senesced side channels) across n?=?17 river sections within which channels were actively migrating. We related areal measures of recruitment and attrition to the density of anthropogenic side channel plugs across river sections. Consistent with our hypothesis, a positive spatial relationship existed between the density of anthropogenic plugs and side channel attrition, but no relationship existed between plug density and side channel recruitment. Our work highlights important linkages among side channel plugs and the persistence and restoration of side channels across floodplain landscapes. Specifically, management of small plugs represents a low-cost, high-benefit restoration opportunity to facilitate scouring flows in side channels to enable the persistence of these habitats over time.     

Fire resistance of passive fire protection coatings after long-term weathering

Passive fire protection (PFP) systems are widely used by the oil, gas and chemical industries to protect offshore and onshore facilities against the effects of fire. However, there are concerns that the performance of PFP systems in a fire may have deteriorated because of weathering and/or that corrosion of the protected item may be taking place beneath the PFP systems. In May 1987, Shell UK began a long-term PFP weathering programme at a maritime test site using furnace tests to assess the fire performance of the materials. The programme was handed over to the Health and Safety Executive in October 1999 and was continued and extended to include the more severe jet fire testing of weathered specimens. This paper describes the effects of weathering on six epoxy intumescent PFP products and one cementitious PFP product in common use. The results are discussed in relation to alterations in physical form, corrosion of the substrate and changes in fire resistance.     

Mapping species distributions: A comparison of skilled naturalist and lay citizen science recording

To assess the ability of traditional biological recording schemes and lay citizen science approaches to gather data on species distributions and changes therein, we examined bumblebee records from the UK’s national repository (National Biodiversity Network) and from BeeWatch. The two recording approaches revealed similar relative abundances of bumblebee species but different geographical distributions. For the widespread common carder (Bombus pascuorum), traditional recording scheme data were patchy, both spatially and temporally, reflecting active record centre rather than species distribution. Lay citizen science records displayed more extensive geographic coverage, reflecting human population density, thus offering better opportunities to account for recording effort. For the rapidly spreading tree bumblebee (Bombus hypnorum), both recording approaches revealed similar distributions due to a dedicated mapping project which overcame the patchy nature of naturalist records. We recommend, where possible, complementing skilled naturalist recording with lay citizen science programmes to obtain a nation-wide capability, and stress the need for timely uploading of data to the national repository.     

Duration and characteristics of metal price cycles

This paper addresses the fluctuations in real metal prices: are they simply random variations or do they display some degree of cyclicality? This study identifies peaks and troughs in the inflation adjusted prices for 14 metals, using monthly average data from January 1947 through December 2007. Duration dependence testing, which is performed on the expansions, contractions, and full cycles, finds many cases in which the duration of these phases are not purely random and have some degree of cyclicality. Additional characterization show that contractions generally persist longer than expansions (in contrast to macroeconomic cycles) that long-term real prices have been trendless, and that the amplitude of price changes over the phases has little regularity. For those performing this type of analysis, the appendices explain the procedures for dating turning points and assessing duration dependence.     

Development and Integration of Quantitative Real-Time PCR Methods for Detection of Mitochondrial DNA and Methanobrevibacter smithii nifH Gene as Novel Microbial Source Tracking Tools

A novel microbial source tracking (MST) method based on the detection of human and non-human markers was developed and applied to track the origin of fecal pollution in water systems. Mitochondrial DNA sequences were used to develop new quantitative real-time polymerase chain reaction (qPCR) assays for dog, poultry, and gull. The targets were included as part of a toolbox including human, cow, pig, and sheep assays. A primer and probe set for the detection of the human-specific nifH gene of Methanobrevibacter smithii was also designed as an indicator of human fecal contamination. The assays were tested for specificity and applied to fecal-spiked surface waters and environmental samples collected from two river catchments impacted by sources of human and non-human fecal contamination. The MST methods described were applicable to both spiked waters and environmental samples, and using the two approaches the origin of fecal pollution could be successfully determined in mixed source fecally polluted waters.     

Expert Witnesses and Environmental Ldtigation

Environmental legislation is developing rapidly. In addition, considerable attention is being given to the environmental impact of new technological developments. Governments as well as citizens, often through organized groups are placing unprecedented pressures on many industries and even on other parts of the government. Popular feeling has been extremely strong on such matters and resistance so far has not been strong. This is likely to change substantially and the future may see a rapid increase in the number of environmental suits especially if the continued existence of certain industries is threatened. Expert evidence will be needed to support government legislation and to support actions to preserve the environment. Such measures will have inevitable economic implications and will evoke predictable responses. Reconciling these viewpoints will provide a challenge for the community which will probably depend to a larger extent on interpretation in courts of -law. The ability of various experts to give advice through the legal process will be essential if the most effective compromises are to be found. It is the purpose of this paper to discuss the gathering and use of such scientific evidence in environmental lawsuits.     

Review of Statistics of Extreme Values with Applications to Air Quality Data

In the field of air pollution control, the rare event is often of more significance than the common event. This is evidenced by the content of air quality standards which define acceptable upper limits of air pollution concentrations and acceptable frequencies with which such concentrations can be exceeded. The principles of extreme value statistics provide important tools for analyzing air quality data in an appropriately significant context.

Part II of the paper presents applications of the theory to air quality data. First, application is made to decisions regarding the length of air monitoring experiments and the length of data records for dis-person analyses. The theory is then applied to the analysis of long term air pollution data collected by the South Coast Air Pollution Control District. The interrelations between extremes from monthly and annual samples are noted and are shown to be consistent with theory.     

COMPLEX I and II Model Performance Evaluation in Nevada and New Mexico

The COMPLEX I and COMPLEX II Gaussian dispersion models for complex terrain applications have been made available by EPA. Various terrain treatment options under IOPT(25) can be selected for a particular application, one of which [IOPT(25) = 1] is an algorithm similar to that of the VALLEY model. A model performance evaluation exercise involving three of the available options with both COMPLEX models was carried out using SF⁶ tracer measurements taken during worst-case stable impaction conditions in complex terrain at the Harry Allen Plant site in southern Nevada. The models did not reproduce observed concentrations on an event by event basis, as correlation coefficients for 1-h concentrations of 0-0.3 were exhibited. When observed and calculated cumulative frequency distributions for 1-h and 3-h concentrations were compared, a close correspondence between observations and concentrations calculated with COMPLEX I, IOPT(25) = 2 or 3 was noted; both options consistently overestimated observed concentrations. With IOPT(25) = 1, upper percentile (maximum) values in the calculated frequency distribution exceeded the corresponding IOPT(25) = 2 or 3 value by roughly a factor of 2, and observed values by 2.5-5. COMPLEX II typically produced maximum values 2-4 times as great as COMPLEX I for the same terrain treatment option. From these results it is concluded that: 1) the physically unrealistic sector-spread approach used in VALLEY and COMPLEX I under stable impaction conditions is a surrogate for wind direction variation, and 2) the doubling of the plume centerline concentration due to ground reflection under terrain impingement conditions that is included in IOPT(25) = 1 is inappropriate.

These findings were found to be consistent with an analysis of noncurrent observed and calculated SO₂ χ/Q frequency distributions for 1, 3, and 24 hours near the Four Corners Plant in New Mexico. The comparison involved a four-year calculated χ/Q data set and a two-year observed χ/Q data set at the worst-case high terrain impact location near the plant.     

Abatement of Ammonia and Hydrogen Sulfide Emissions from a Swine Lagoon Using a Polymer Biocover

ABSTRACT

The purpose of this research was to determine the efficiency of a polymer biocover for the abatement of H₂S and NH₃ emissions from an east-central Missouri swine lagoon with a total surface area of 7800 m². The flux rate of NH₃, H₂S, and CH₄ was monitored continuously from two adjacent, circular (d = 66 m) control and treatment plots using a nonintrusive, micrometeorological method during three independent sampling periods that ranged between 52 and 149 hr. Abatement rates were observed to undergo a temporal acclimation event in which NH₃ abatement efficiency improved from 17 to 54% (p = <0.0001 to 0.0005) and H₂S abatement efficiency improved from 23 to 58% (p < 0.0001) over a 3-month period. The increase in abatement efficiency for NH₃ and H₂S over the sampling period was correlated with the development of a stable anaerobic floc layer on the bottom surface of the biocover that reduced mass transfer of NH₃ and H₂S across the surface. Analysis of methanogenesis activity showed that the biocover enhanced the rate of anaerobic digestion by 25% when compared with the control. The biocover-enhanced anaerobic digestion process was shown to represent an effective mechanism to counteract the accumulation of methanogenic substrates in the biocovered lagoon.