Male production in the antMyrmica ruba L.     

Brian M. V. 《Journal of pest science》1971,44(5):80

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Male production in the antMyrmica ruba L.

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Stress wave sorting of red maple logs for structural quality     

Xiping?WangEmail author  Robert?J.?Ross  David?W.?Green  Brian?Brashaw  Karl?Englund  Michael?Wolcott 《Wood Science and Technology》2004,37(6):531-537

Existing log grading procedures in the United States make only visual assessments of log quality. These procedures do not incorporate estimates of the modulus of elasticity (MOE) of logs. It is questionable whether the visual grading procedures currently used for logs adequately assess the potential quality of structural products manufactured from them, especially those for which MOE is of primary concern. The purpose of this study was to investigate the use of stress wave nondestructive evaluation techniques to sort red maple logs for the potential quality of lumber obtained from them. Ninety-five red maple logs were nondestructively evaluated using longitudinal stress wave techniques and sorted into four stress wave grades. The logs were then sawn into cants and lumber. The same procedure was used to obtain stress wave times in the cants and lumber. The lumber specimens were then dried and graded using a transverse vibration technique. The results of this study showed that good relationships existed between stress wave times measured in logs, cants, and the lumber produced from the logs. It was found that log stress wave grades have positive relationships with the lumber grades. Logs with high stress wave grades produced high-grade lumber. These findings indicate that the longitudinal stress wave technique has potential in sorting logs and cants for the production of high MOE products.The Forest Products Laboratory is maintained in cooperation with the University of Wisconsin. This article was written and prepared by U.S. Government employees on official time, and it is therefore in the public domain and not subject to copyright.  相似文献   

Short-term response of salal (Gaultheria shallon Pursh) to commercial harvesting for floral greenery     

Wendy Cocksedge  Brian D. Titus 《Agroforestry Systems》2006,68(2):103-111

Salal (Gaultheria shallon Pursh), which is widely used for floral greenery, is an important non-timber forest product (NTFP) from the coastal forests of the Pacific Northwest of North America. However, there are no known studies on the impacts of commercial salal harvesting on subsequent growth. A study was therefore initiated to quantify the growth of salal 1 year after commercial harvesting, and to compare this with growth of unharvested salal. The amount of biomass removed from shrubs through commercial harvesting (131 g m⁻²) was the same as the amount of annual growth in adjacent undisturbed plots (135 g m⁻²). One year later, the amount of regrowth in previously harvested plots (144 g m⁻²) was greater than the amount of new growth in adjacent undisturbed plots (111 g m⁻²). As there was little difference in the weight per current stem, the increased biomass after commercial harvesting was attributed to the observed increase in stem number (60 stems m⁻²) as compared to undisturbed salal (50 stems m⁻²). Our study does not incorporate either repeated annual harvesting or variable harvesting intensities, both of which have been anecdotally reported to affect levels of re-growth and therefore sustainability.  相似文献   

Assessment of allometric algorithms for estimating leaf biomass, leaf area index and litter fall in different-aged Sitka spruce forests   总被引：1，自引：0，他引：1  

Tobin  Brian; Black  Kevin; Osborne  Bruce; Reidy  Brian; Bolger  Tom; Nieuwenhuis  Maarten 《Forestry》2006,79(4):453-465

The relationship between leaf area and diameter at breast height(d.b.h.) or sapwood area (AS) has been used to estimate standleaf area or biomass of forest canopies. It has been suggestedthat intra-specific variations in the relationship between standleaf area and d.b.h. or AS can introduce a systematic errorin these estimates for younger and older stands unless additionalparameters relating to canopy structure are included in allometricfunctions. We collected data from a Sitka spruce chronosequenceto parametrize and test different algorithms for the estimationof foliar biomass (FB) and litter inputs over a range of forestages. FB estimates were significantly improved when additionalbiometric information relating to crown structure (canopy opennessand height of live crown) was included in the models. Althoughthe use of the relationship between leaf area and AS for theestimation of leaf area is justified by theoretical considerations(pipe model theory), we show that d.b.h. and other canopy parametersprovided the most robust estimation of leaf area across different-agedstands. Our results also suggest that the accuracy of litterinput estimates depends on needle retention time and annualturnover rate, particularly immediately before and after canopyclosure.  相似文献   

Enhanced inactivation of avian influenza virus at ?20°C by disinfectants supplemented with calcium chloride or other antifreeze agents     

Jiewen Guan  Maria Chan  Brian W. Brooks  Elizabeth Rohonczy 《Canadian journal of veterinary research》2015,79(4):347-350

Avian influenza outbreaks have occurred during winter months, and effective disinfection of poultry premises at freezing temperatures is needed. The commercial disinfectants Virkon and Accel, supplemented with an antifreeze agent [propylene glycol (PG), methanol (MeOH), or calcium chloride (CaCl₂)], were evaluated for their effectiveness in killing avian influenza virus (AIV) at −20°C or 21°C. An AIV suspension was applied to stainless steel disks, air-dried, and covered with a disinfectant or antifreeze agent for 5 to 30 min. Virkon (2%) and Accel (6.25%) with 30% PG, 20% MeOH, or 20% CaCl₂ inactivated 6 log₁₀ AIV within 5 min at −20°C and 21°C. At these temperatures PG and MeOH alone did not kill AIV, but the 20% CaCl₂ solution alone inactivated 5 log₁₀ AIV within 10 min. The results suggested that CaCl₂ is potentially useful to enhance the effectiveness of disinfection of poultry facilities after outbreaks of AIV infection in warm and cold seasons.  相似文献   

Clinical,histopathological and immunohistochemical characterization of a novel equine ocular disorder: heterochromic iridocyclitis with secondary keratitis in adult horses          下载免费PDF全文

Nelson I. Pinto  Richard J. McMullen Jr.  Keith E. Linder  John M. Cullen  Brian C. Gilger 《Veterinary ophthalmology》2015,18(6):443-456

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Insecticidal and anti-microbial activity of bio-oil derived from fast pyrolysis of lignin,cellulose, and hemicellulose     

Hossain  Mohammad M.  Scott  Ian M.  McGarvey  Brian D.  Conn  Kenneth  Ferrante  Lorenzo  Berruti  Franco  Briens  Cedric 《Journal of pest science》2015,88(1):171-179

Journal of Pest Science - Conflicting views regarding synthetic pesticides include the successful use as pest management tools for agriculture and forestry on one hand and the threats to components...  相似文献   

Silicon reduces slug feeding on wheat seedlings     

Griffin  Mark  Hogan  Brian  Schmidt  Olaf 《Journal of pest science》2015,88(1):17-24

Journal of Pest Science - Slugs are a serious pest of cereal crops, and recent emphasis in slug pest management has shifted from solely chemical towards integrated approaches. The objective of the...  相似文献   

Processes affecting the dissipation of the herbicide isoxaflutole and its diketonitrile metabolite in agricultural soils under field conditions     

Papiernik SK  Yates SR  Koskinen WC  Barber B 《Journal of agricultural and food chemistry》2007,55(21):8630-8639

Two-year field dissipation studies were conducted in three soil types in Minnesota to examine the processes affecting the dissipation of the herbicide isoxaflutole and its phytotoxic diketonitrile metabolite (DKN) under relatively cool, wet soil conditions. Plots of cuphea were treated with isoxaflutole and potassium bromide, a nonsorbed, nondegraded tracer. Replicate soil cores were collected six times during the growing season to a depth of 1 m, and the bromide or herbicide concentration was measured in each of five depth increments. The dissipation half-life (DT50) of isoxaflutole + DKN was 8-18 days in each soil. Bromide and herbicide concentrations were low at depths >40 cm throughout the study, and herbicide concentrations in soil 100 days after application were usually undetectable. Simulation modeling using Hydrus-1D for the loam soil suggested that plant uptake was an important mechanism of dissipation.  相似文献   

Coaches’ Attitudes Toward Campus Board Training in Adolescent Climbers in the United States     

Christopher W. McMullen  Brian J. Mugleston  Lyndsey N. Booker 《The Forestry Chronicle》2021,32(2):168-175

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