Setting Analyst: An Operational Harvest Planning Tool

Operational harvest planning in the southern USA has not been widely used in the past due to a lack of state legislation, non-regulatory water quality protection programs, and relatively easy logging conditions. Increased government regulation and market pressures to document sustainable forest management under various certification standards is increasing the need for harvest planning in the region, particularly on private, non-industrial timber sales. We developed an ArcView extension, Setting Analyst (SA), to assist harvest planners. SA can use spatial information obtained from scanned air photos or detailed data from a geographic information system. It models travel patterns of ground-based machines and compares different harvest settings based on projected average skidding distance, costs of skidding and improvements, and site disturbance levels. In its current form, it does not account for slope. SA can model settings with complex features such as stream crossings, restricted areas, and skidding on designated trails. Travel intensity is assessed since it is highly correlated with site disturbance and soil compaction. To assess the utility of SA, we used it to model ten actual harvesting settings and contrasted each with two proposed settings. SA produced sale plans that were very similar to those observed on the ground. Its primary advantage is that it conveniently documents each alternative setting considered for the timber sale. These can be kept on file to demonstrate the level of planning used when forest certification audits are conducted. SA offers the most potential to harvest planners that already use GIS or GPS but desire additional analysis and documentation capabilities

The effect of proton damage on the X-ray spectral response of MOS CCDs for the swift X-ray telescope

The effect of non-ionising energy loss(NIEL) of protons in charge-coupled devices is to displace silicon atoms and any dopant materials present from their lattice positions to form lattice defects which in turn can trap electrons [1]. A CCD operating as a photon counter for x-ray spectroscopy relies on the efficient transfer of charge from one region to another. The number of defects produced will reduce the charge transfer efficiency (CTE) and hence degrade the spectral resolution of the energy distribution of interest [2]. The Swift X-ray Telescope will be equipped with a single EPIC MOS CCD22 as developed for the XMM project [3]. It is the aim of this study to determine the effect of the radiation environment on the performance of the CCD and its impact on the scientific objective of the x-ray telescope, to probe the x-ray afterglow of Gamma Ray Bursts (GRBs)

Forest processes from stands to landscapes: exploring model forecast uncertainties using cross-scale model comparison

Forest management practices conducted primarily at the stand scale result in simplified forests with regeneration problems and low structural and biological diversity. Landscape models have been used to help design management strategies to address these problems. However, there remains a great deal of uncertainty that the actual management practices result in the desired sustainable landscape structure. To investigate our ability to meet sustainable forest management goals across scales, we assessed how two models of forest dynamics, a scaled-up individual-tree model and a landscape model, simulate forest dynamics under three types of harvesting regimes: clearcut, gap, and uniform thinning. Althougth 50– 100 year forecasts predicted average successional patterns that differed by less than 20% between models, understory dynamics of the landscape model were simplified relative to the scaled-up tree model, whereas successional patterns of the scaled-up tree model deviated from empirical studies on the driest and wettest landtypes. The scale dependencies of both models revealed important weaknesses when the models were used alone; however, when used together, they could provide a heuristic method that could improve our ability to design sustainable forest management practices

Interstellar MHD Turbulence and Star Formation

This chapter reviews the nature of turbulence in the Galactic interstellar medium (ISM) and its connections to the star formation (SF) process. The ISM is turbulent, magnetized, self-gravitating, and is subject to heating and cooling processes that control its thermodynamic behavior. The turbulence in the warm and hot ionized components of the ISM appears to be trans- or subsonic, and thus to behave nearly incompressibly. However, the neutral warm and cold components are highly compressible, as a consequence of both thermal instability in the atomic gas and of moderately-to-strongly supersonic motions in the roughly isothermal cold atomic and molecular components. Within this context, we discuss: i) the production and statistical distribution of turbulent density fluctuations in both isothermal and polytropic media; ii) the nature of the clumps produced by thermal instability, noting that, contrary to classical ideas, they in general accrete mass from their environment; iii) the density-magnetic field correlation (or lack thereof) in turbulent density fluctuations, as a consequence of the superposition of the different wave modes in the turbulent flow; iv) the evolution of the mass-to-magnetic flux ratio (MFR) in density fluctuations as they are built up by dynamic compressions; v) the formation of cold, dense clouds aided by thermal instability; vi) the expectation that star-forming molecular clouds are likely to be undergoing global gravitational contraction, rather than being near equilibrium, and vii) the regulation of the star formation rate (SFR) in such gravitationally contracting clouds by stellar feedback which, rather than keeping the clouds from collapsing, evaporates and diperses them while they collapse.Comment: 43 pages. Invited chapter for the book "Magnetic Fields in Diffuse Media", edited by Elisabete de Gouveia dal Pino and Alex Lazarian. Revised as per referee's recommendation

Fitting the integrated Spectral Energy Distributions of Galaxies

Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Scienc

Can forest management based on natural disturbances maintain ecological resilience?

Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance

Disability activism and the politics of scale

In this paper, we examine the role of spatial scale in mediating and shaping political struggles between disabled people and the state. Specifically, we draw on recent theoretical developments concerning the social construction of spatial scale to interpret two case studies of disability activism within Canada and Ireland. In particular, we provide an analysis of how successful the disability movement in each locale has been at 'jumping scale' and enacting change, as well as examining what the consequences of such scaling-up have been for the movement itself. We demonstrate that the political structures operating in each country markedly affect the scaled nature of disability issues and the effectiveness of political mobilization at different scales