Timber investment returns for selected plantations and native forests in South America and the Southern United States     

Frederick Cubbage  Patricio Mac Donagh  José Sawinski Júnior  Rafael Rubilar  Pablo Donoso  Arnaldo Ferreira  Vitor Hoeflich  Virginia Morales Olmos  Gustavo Ferreira  Gustavo Balmelli  Jacek Siry  Mirta Noemi Báez  José Alvarez 《New Forests》2007,33(3):237-255

Timber investment returns were estimated for the principal exotic and selected native species in the Southern Cone of Latin America and in the Southern United States. Exotic eucalyptus plantations in South America were most profitable, with internal rates of returns (IRRs) ranging from 13% to 23%, followed by exotic loblolly pine, with IRRs from 9% to 17%. Average loblolly pine plantation returns in the US South were less profitable, with an IRR of about 9.5%, and natural forest management in the South had IRRs of 4% to 8%. Subtropical native species plantations of the best araucaria and nothofagus species had reasonable financial returns, with IRRs ranging from 5% to 13%. Subtropical or tropical native forests had fewer commercial timber species, and had much lower growth rates and returns. Their IRRs were less than 4%, or even negative for unmanaged stands. State subsidy payments for forest plantations or for timber stand improvements increased IRRs somewhat and reserving areas for environmental protection reduced their IRRs slightly. Including land costs in the cash flows decreased these internal rates of return substantially. Natural stand returns in Latin America were much less than those of plantations, but management of those stands offered better rates of return than only holding the land.  相似文献   

Heat dissipation sensors of variable length for the measurement of sap flow in trees with deep sapwood   总被引：1，自引：0，他引：1  

James SA  Clearwater MJ  Meinzer FC  Goldstein G 《Tree physiology》2002,22(4):277-283

Robust thermal dissipation sensors of variable length (3 to 30 cm) were developed to overcome limitations to the measurement of radial profiles of sap flow in large-diameter tropical trees with deep sapwood. The effective measuring length of the custom-made sensors was reduced to 1 cm at the tip of a thermally nonconducting shaft, thereby minimizing the influence of nonuniform sap flux density profiles across the sapwood. Sap flow was measured at different depths and circumferential positions in the trunks of four trees at the Parque Natural Metropolitano canopy crane site, Panama City, Republic of Panama. Sap flow was detected to a depth of 24 cm in the trunks of a 1-m-diameter Anacardium excelsum (Bertero & Balb. ex Kunth) Skeels tree and a 0.65-m-diameter Ficus insipida Willd. tree, and to depths of 7 cm in a 0.34-m-diameter Cordia alliodora (Ruiz & Pav.) Cham. trunk, and 17 cm in a 0.47-m-diameter Schefflera morototoni (Aubl.) Maguire, Steyerm. & Frodin trunk. Sap flux density was maximal in the outermost 4 cm of sapwood and declined with increasing sapwood depth. Considerable variation in sap flux density profiles was observed both within and among the trees. In S. morototoni, radial variation in sap flux density was associated with radial variation in wood properties, particularly vessel lumen area and distribution. High variability in radial and circumferential sap flux density resulted in large errors when measurements of sap flow at a single depth, or a single radial profile, were used to estimate whole-plant water use. Diurnal water use ranged from 750 kg H2O day-1 for A. excelsum to 37 kg H2O day-1 for C. alliodora.  相似文献   

Tree establishment and growth using forage ground covers in an alley-cropped system in Midwestern USA     

Kathleen?DelateEmail author  Eric?Holzmueller  DeAnn Davis?Frederick  Carl?Mize  Charles?Brummer 《Agroforestry Systems》2005,65(1):43-52

The integration of forage crops in an alley-cropped system was examined as a method of encouraging tree planting to increase farm income, improve soil quality, and enhance biodiversity on Midwestern U.S. farms. Crop and tree performance were evaluated in an alley-cropped system using four forage intercrops grown in tree alleyways to simulate a potential hay crop – oat (Avena sativa L.) and red clover (Trifolium pratense L.); oat, red clover, and red fescue (Festuca rubra L.); oat, red clover, and orchardgrass (Dactylis glomerata L.); and oat and hairy vetch (Vicia villosa Roth) – compared to a herbicide, mowing and control (no management) treatment. Five tree species, divided into fast-growing hardwoods of two poplar (Populus spp.) clones [Crandon (P. alba L. × P. grandidentata Michx.) and Eugenei (P. deltoids Bartr. × P. nigra L.)], and silver maple (Acer saccharinum L.) were compared with two high-value, slow-growing hardwoods planted from seed and as seedlings: red oak (Quercus rubra L.) and black walnut (Juglans nigra L.). Tree survival in the first year was greater for the fast-growing species, and by the fourth year, tree height among the four forage treatments was equivalent for all upland locations. The oat/hairy vetch ground cover was associated with the shortest trees in the bottomland site. Herbicide-treated trees were taller than the average of the four forage treatments for all four planting conditions. Tree height in the mowing and the control treatments was not significantly different for all four planting conditions. The nutritive value of the forage crop was excellent in the second year of tree establishment, with crude protein content and digestibility at 17 and 71%, respectively, in the oat/red clover/red fescue treatment, suggesting the viability of forage crops as alternatives to herbicides in alley-cropped systems.  相似文献   

Early detection of brown-rot decay in southern yellow pine using immunodiagnostic procedures     

Carol A. Clausen  Frederick Green III  Terry L. Highley 《Wood Science and Technology》1991,26(1):1-8

Summary Immunodiagnostic procedures have been used to detect incipient decay of southern yellow pine by six common brown-rot fungi. Rabbit polyclonal antibodies were raised to liquid culture fractions of the six fungi. The antibodies, after preadsorption to sawdust, were tested in particle agglutination assays, immuno-dot blot, and enzyme-linked immunosorbent assay (ELISA) for their ability to detect the decay organisms when they were grown in southern yellow pine. Results were correlated to wood-block weight loss.Each method specifically detected five of the six test organisms at very low wood-block weight loss. Agglutination assays were the least effective and lacked the sensitivity of the other assays, even though the latex particles were more sensitive and reproducible than charcoal particles. Cross-reactivity was noted only for one of the control organisms and only in the charcoal agglutination assay. Both dot blot and ELISA were sensitive test methods, but ELISA had the advantage of quantification. We feel that two of these assays, latex for presumptive results and ELISA for definitive results, could effectively detect incipient decay of common brown-rot fungi.  相似文献   

Polymorphisms of 5' flanking region of chicken prolactin gene   总被引：9，自引：0，他引：9  

Liang Y  Cui J  Yang G  Leung FC  Zhang X 《Domestic animal endocrinology》2006,30(1):1-16

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The path forward for biofuels and biomaterials   总被引：3，自引：0，他引：3  

Ragauskas AJ  Williams CK  Davison BH  Britovsek G  Cairney J  Eckert CA  Frederick WJ  Hallett JP  Leak DJ  Liotta CL  Mielenz JR  Murphy R  Templer R  Tschaplinski T 《Science (New York, N.Y.)》2006,311(5760):484-489

Biomass represents an abundant carbon-neutral renewable resource for the production of bioenergy and biomaterials, and its enhanced use would address several societal needs. Advances in genetics, biotechnology, process chemistry, and engineering are leading to a new manufacturing concept for converting renewable biomass to valuable fuels and products, generally referred to as the biorefinery. The integration of agroenergy crops and biorefinery manufacturing technologies offers the potential for the development of sustainable biopower and biomaterials that will lead to a new manufacturing paradigm.  相似文献   

Public health and policy     

Nunnery J  Angulo FJ  Tollefson L 《Preventive veterinary medicine》2006,73(2-3):191-195

Antimicrobial agent usage data are essential for focusing efforts to reduce misuse and overuse of antimicrobial agents in food producing animals because these practices may select for resistance in bacteria of animals. Transfer of resistant bacteria from animals to humans can lead to human infection caused by resistant pathogens. Resistant infections can lead to treatment failures, resulting in prolonged or more severe illness. Multiple World Health Organization (WHO) reports have concluded that both antimicrobial resistance and antimicrobial usage should be monitored on the national level. The system for collecting antimicrobial usage data should be clear and transparent to facilitate trend analysis and comparison within and among countries. Therapeutic, prophylactic and growth promotion use should be recorded, along with route of administration and animal species and/or production class treated. The usage data should be compared to resistance data, and the comparison should be made available in a timely manner. In the United States, surveillance of antimicrobial resistance in foodborne bacteria is performed by the National Antimicrobial Resistance Monitoring System (NARMS) for enteric bacteria, however, the United States still lacks a mechanism for collecting antimicrobial usage data. Combined with antimicrobial resistance information from NARMS, antimicrobial usage data will help to direct education efforts and policy decisions, minimizing the risk that people will develop antimicrobial resistant infections as a result of eating food of animal origin. Ultimately mitigation strategies guided by usage data will be more effective in maintaining antimicrobial drugs for appropriate veterinary use and in protecting human health.  相似文献   

New isocoumarins and alkaloid from Chinese insect medicine, Eupolyphaga sinensis Walker     

Jiang HL  Luo XH  Wang XZ  Yang JL  Yao XJ  Crews P  Valeriote FA  Wu QX 《Fitoterapia》2012,83(7):1275-1280

Two new isocoumarins (1 and 2), a new alkaloid (3), and a known N-acetyldopamine dimer (4) were isolated from the ethyl acetate extract of Chinese insect medicine Eupolyphaga sinensis. Their structures were elucidated on the basis of detailed spectroscopic investigations, such as 1D- and 2D NMR spectroscopy, as well as by means of HR-MS. The structure of 1 was firmly confirmed by X-ray crystallography, and the absolute configuration was revealed by experimental and computational optical rotation analyses. Cytotoxicities of 1-4 were measured in vitro against 10 selected cancer cell lines.  相似文献   

Canada's inter‐agency wild bird influenza survey     

Jane PARMLEY  Stéphane LAIR  Frederick A. LEIGHTON 《Integrative zoology》2009,4(4):409-417

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Timing of magnesium supplementation administered through drinking water to improve fresh and stored pork quality   总被引：8，自引：0，他引：8  

Frederick BR  van Heugten E  See MT 《Journal of animal science》2004,82(5):1454-1460

Thirty-two pigs were used to determine the timing effect of magnesium (Mg) supplementation given through drinking water on pork quality. Pigs (16 barrows and 16 gilts) were individually penned, provided 2.7 kg of feed (0.12% Mg) daily (as-fed basis), and allowed free access to water via a nipple waterer for the duration of the study. After 5 d of adjustment, pigs (120 +/- 0.8 kg BW) were allotted randomly by weight and sex to 900 mg/L of supplemental Mg from magnesium sulfate heptahydrate in drinking water for -6, -4, -2, or 0 d relative to slaughter. The LM and semimembranosus (SM) muscles were removed 24 h postmortem. Retail display storage was simulated for 8 d, and the LM was vacuum-packaged for 25 or 50 d at 4 degrees C. Magnesium did not affect the pH of the LM at either 45 min (P = 0.15) or 24 h postmortem (P = 0.23). However, the pH of the SM at 24 h postmortem tended to be greater (P = 0.08) for pigs consuming Mg for 2 d than for those not supplemented. Fluid loss after 8 d of storage was less (P < 0.05) in the LM of pigs supplemented with Mg for 6 d than in those without supplementation. Furthermore, fluid loss from the SM of pigs provided supplemental Mg for 2 d, but not for 4 or 6 d, was lower (P < 0.05) on each day of retail display than the SM of unsupplemented pigs. Minolta L*, a*, and b* color measurements of the LM during display storage were not (P > 0.10) affected by Mg supplementation. However, Mg supplementation for 2 or 4 d decreased paleness (lower L* value) after 25 d (P < 0.05), but not 50 d (P > 0.10) of vacuum-packaged storage. Magnesium addition for 2 d decreased the extent of oxidation (thiobarbituric acid-reactive substances) of the LM after 4 d of display storage compared with 0 d of Mg (P < 0.05). Oxidation of the SM during 8 d of display storage increased linearly (P < 0.05) as duration of supplementation increased from 2 to 6 d but did not differ (P = 0.22) from 0 d of Mg supplementation. Although the response to Mg supplementation was variable, supplementation for 2 d before slaughter was considered most efficacious because of the following: decreased fluid loss from the SM, and lower lipid oxidation formation in the LM during retail storage; a darker, more desirable LM color after 25 d of vacuum-packaged storage; and cost reductions compared with longer durations.  相似文献