The unexpected resurgence of Weyl geometry in late 20-th century physics

Weyl's original scale geometry of 1918 ("purely infinitesimal geometry") was withdrawn by its author from physical theorizing in the early 1920s. It had a comeback in the last third of the 20th century in different contexts: scalar tensor theories of gravity, foundations of gravity, foundations of quantum mechanics, elementary particle physics, and cosmology. It seems that Weyl geometry continues to offer an open research potential for the foundations of physics even after the turn to the new millennium.Comment: Completely rewritten conference paper 'Beyond Einstein', Mainz Sep 2008. Preprint ELHC (Epistemology of the LHC) 2017-02, 92 pages, 1 figur

Ecological effects of alternative fuel-reduction treatments: highlights of the National Fire and Fire Surrogate study (FFS)

The 12-site National Fire and Fire Surrogate study (FFS) was a multivariate experiment that evaluated ecological consequences of alternative fuel-reduction treatments in seasonally dry forests of the US. Each site was a replicated experiment with a common design that compared an un-manipulated control, prescribed fire, mechanical and mechanical + fire treatments. Variables within the vegetation, fuelbed, forest floor and soil, bark beetles, tree diseases and wildlife were measured in 10-ha stands, and ecological response was compared among treatments at the site level, and across sites, to better understand the influence of differential site conditions. For most sites, treated stands were predicted to be more resilient to wildfire if it occurred shortly after treatment, but for most ecological variables, short-term response to treatments was subtle and transient. Strong site-specificity was observed in the response of most ecosystem variables, suggesting that practitioners employ adaptive management at the local scale. Because ecosystem components were tightly linked, adaptive management would need to include monitoring of a carefully chosen set of key variables. Mechanical treatments did not serve as surrogates for fire for most variables, suggesting that fire be maintained whenever possible. Restoration to pre-settlement conditions will require repeated treatments over time, with eastern forests requiring more frequent applications.Keywords: Oak, Prescribed fire, Frequent fire regimes, Pine, Mechanical treatment, Forest thinning, Dry forest management, Seasonally dry forest

Creating Stand-Level Prescriptions that Integrate Ecological and Fuel Management Objectives across the Eastern Cascades – a Workshop

The primary goal of this workshop was to develop a range of fuel reduction prescriptions that integrate fuel and ecological objectives specifically related to northern spotted owl (NSO) conservation in dry forests of the Cascade Range in eastern Washington and Oregon and northern California. The workshop was held at the Eagle Crest Resort, Redmond, Oregon, from October 13-15, 2009. Over 200 managers and scientists attended from California, Oregon, and Washington. Most (82%) of the 194 people who formally registered for the workshop worked for federal land management, research, or regulatory agencies. The rest were a mix of university faculty and graduate students (7%), representatives of private non-governmental groups (6%), staff from state resource or wildlife agencies (3%), and staff of tribal governments (2%). Most registrants were from Oregon (63%), followed by California (19%) and Washington (17%). We attracted a mix of managers and scientists. Wildlife biologists made up 40% of the registrants, followed by silviculturists (24%) and fire specialists (14%). Many people professed primary or secondary expertise in botany, ecology, forest health (entomology, pathology), or planning. The workshop began in the first afternoon with presentations on the scientific basis for dry-forest management and current management and ecological objectives and issues. The second full day was devoted to defining stand management objectives, learning about current management efforts in the region, and two group exercises to define objectives and treatment strategies. The AM of the last day started with 2 hours of discussion of the previous afternoon’s break-out discussions. Two talks on landscape planning followed. A final talk discussed options to best implement, test, and improve on the workshop outcomes. An adaptive management template and regional study network were proposed. The PM of the last day was a field trip to Pringle Falls Experimental Forest attended by about 100 people. A consensus developed that prescriptions most likely to successfully integrate ecological and fuel-management objectives in both mixed-conifer and pine-dominated forests should be based on emulating historic distributions of forest patch and gap sizes. Both scientists and field managers are anxious to participate in a coordinated management study network, recognizing this approach as the most efficient means for gaining reliable information. Key information needs include answers to the questions: (1) How do NSOs respond to different levels of dry forest treatment in both the short and long term?; and, (2) What methods (marking, logging systems, etc.) are most effective at producing the desired pattern of spatial heterogeneity within and among stands? The workshop results and networking will feature strongly in several ongoing research, management, and science delivery efforts across the region

Using weighted distance and least-cost corridor analysis to evaluate regional-scale large carnivore habitat connectivity in Washington

Population fragmentation and isolation are primary concerns for conservation of large carnivores. Highways are often important landscape features contributing to regional-scale habitat fragmentation for these species. We used GIS weighted distance and least-cost corridor techniques to map relative landscape permeability and landscape linkages for large carnivores in Washington and adjacent portions of Idaho and British Columbia. Landscape permeability was modeled based on land cover, road density, human population density, and topography. We identified six concentrations of large carnivore habitat, including the British Columbia Coast Range, the North Cascades, the South Cascades, the Kettle-Monashee Ranges, the Selkirk-Columbia Ranges, and the Olympic Mountains. The model highlighted four landscape linkage areas of potential importance for large carnivores including the Fraser River area (B.C.), Snoqualmie Pass (Wa), the Okanogan Valley (Wa. and B.C.), and the Upper Columbia River area (Wa. and B.C.). We also modeled landscape linkages in southwestern Washington, between the South Cascades and Olympics, however the resistance to movement in this landscape was extremely high. We expect that southwestern Washington is impermeable to long-distance movements for our focal species. GIS overlays of the Washington state highway network on our landscape permeability and linkage maps indicated that, in the vicinity of the Cascades and northeastern Washington, 497 miles (800 km) of state highway passed through areas accessible to large carnivore intra-territorial movement, and 234 miles (377 km) of state highway passed through landscape linkage areas that may be important for inter-territorial movement. [Funding for this project was provided by the Washington State Department of Transportation, and the USDA Forest Service, PNW Research Station under the Northwest Forest Plan.

Bushy-tailed woodrat abundance in dry forests of eastern Washington

We studied bushy-tailed woodrats (Neotoma cinerea occidentalis) in the eastern Washington Cascade Range to estimate their density and survival in 3 typical dry forest cover types. We predicted woodrat density to be high, moderate, and low in mature mixed-conifer forests, young mixed-conifer forests, and open ponderosa pine forests, respectively. We livetrapped on 8 Â 8 grids (280 m) over an 8-day period each autumn for 4 years to obtain Huggins mark-recapture estimates of woodrat density. We captured woodrats 617 times and marked 193 individual woodrats in 12 sample stands during 42,165 trap nights. The sex ratio of captures was 62% female and 38% male. Adults made up 79% of captures. Woodrat density averaged 0.49 animals/ha among all cover types and years; woodrat density did not differ among types. Regardless of cover type, stands fell into 4 woodratdensity groups, with densities ranging from 0.13 to 0.93 woodrats/ha. Classification tree analysis revealed that woodrat-density groups could be predicted well (proportional reduction in error ¼ 0.73 to 0.89) by the type and amount of cover provided by large snags, mistletoe brooms, and soft downed logs. Over the 4-year period, woodrat density ranged from 0.28 animals/ha to 0.87 animals/ha, increasing each year at a rate of k ¼ 1.8 consistently among cover types. A moderate (r ¼ 0.55) density-dependent response in per capita rate of increase was detected. The apparent annual survival rate was a low 0.14. Management to reduce woody fuels and to restore low-intensity high-frequency fire regimes in ponderosa pine and dry Douglas-fir forest likely will reduce bushy-tailed woodrat populations unless prescriptions can mitigate the loss of snag, mistletoe, and downed log cover

Truffle abundance and mycophagy by northern flying squirrels in eastern Washington forests

Although much is known about truffle abundance and rodent mycophagy in mesic Douglas-fir forests in the Pacific Northwest, few data are available for dry interior montane forests dominated by ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), and grand fir (Abies grandis). Our objective was to quantify the relationship between the abundance and diversity of ectomycorrhizal fungal sporocarps in the soil and in the diets of northern flying squirrels (Glaucomys sabrinus) in low-elevation forests of the eastern Washington Cascades. We randomly sampled four stands each of three cover types: dry open ponderosa pine, mesic young mixed-conifer forest, and mesic mature mixed-conifer forest. We sampled the soil for hypogeous sporocarps during the spring of 1999 and 2000. We collected fecal pellets from 318 flying squirrels live-trapped during the fall of 1997–2000. We sampled 2400 m2 of soil surface and found truffles in 40% of 600 plots. Total biomass collected was 609 g. Spring truffle biomass on a kg/ha basis averaged 1.72 in open pine, 3.56 in young, and 4.11 in mature forest. Twenty-two species were collected across all cover types, with all but three species belonging to the Basidiomycotina. Eleven dominant species accounted for 91–94% of truffle biomass in each cover type. Four dominant species accounted for 60–70% of spring truffle biomass: Gautieria monticola, Hysterangium coriaceum, Rhizopogon parksii, and R. vinicolor. Truffle assemblages, richness and total biomass differed among cover types: richness and biomass were highest in young and mature mixed-conifer forest, and lowest in open ponderosa pine forest. Fall squirrel diets were composed of 23 genera or groups of fungi, plus about 22% plant material. Rhizopogon was the most abundant genus in the diet, followed by plant material, then Gautieria, Leucogaster, Alpova, and Hysterangium. Diets in different cover types were similar in the composition, richness, evenness, and the ratio of fungus to plant material. Diet richness varied over the study period. Nineteen truffle genera were detected in fall fecal samples versus 12 in spring soil samples. Management of low-elevation dry forest to maintain or restore stable fire regimes might reduce truffle diversity at stand scales by simplifying stand composition and structure; but, such management might increase long-term beta and landscape truffle diversity and persistence by reducing the occurrence of high-intensity fires and stabilizing inherent fire disturbance regimes

Short-Term Responses of Red Squirrels to Prescribed Burning in the Interior Pacific Northwest, USA

We quantified changes in density of red squirrels (Tamiasciurus hudsonicus) in response to prescribed fire in mixed coniferous forests of Idaho and Washington, USA, using a Before-After-Control-Impact design. We found no evidence that low-severity prescribed fires affected density of red squirrels; we estimated the change in red squirrel densities due to prescribed fire as 20.15 squirrels/ ha (95% CI = 5 -0.405-0.105). Squirrel density did, however, increase with increasing live tree density, shrub cover, and density of large downed logs, and varied across years and states. These results indicate that land managers implementing prescribed fire treatments to reduce fuel loads on public lands can reduce the impacts of fire on squirrel populations by formulating prescriptions to retain large live trees and large downed logs.</p