摘要:

A sustainable yield management system is proposed forEuterpe edulis(‘Palmiteiro’) based on field studies. Since this Brazilian palm integrates the forest in the intermediate succession stages and grows naturally in shaded areas, its exploitation requires neither forest destruction nor forest gaps. This system, based on the cyclic exploitation and on equating species exploitation, was accomplished by defining three basic parameters: (i) the number of seed producing trees per area and their maintenance to ensure natural regeneration and the maintenance of population genetic structure and diversity levels, (ii) the available stock, used to determine the degree of exploitation, and (iii) the species increment rates in order to define the cutting cycle length. These parameters were estimated from permanent plot inventories. In São Pedro de Alcântara (SC), the exploitation of ‘palmiteiro’ trees with diameter at breast height above 8.5 cm, leaving 50 seed producing trees, yields 51.2 kg/ha of heart-of-palm (‘palmito’) in the first cycle. The sustainable yield management of this palm tree is (i) important to conservation because it allows the demographic and genetic structure maintenance, and (ii) economically viable because its edible product, the heart-of-palm, which has high economic value, can provide subsistence to several traditional communities.

ISSN:1054-9811    

DOI:10.1300/J091v11n03_01

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Non-timber forest products (NTFPs) are important in rural southwest Virginia as a source of household income. Marketing system of crafts, medicinal and herbal, and specialty wood products are studied using exploratory and qualitative research methods. Fifty market players at various levels in marketing chains are interviewed to get the information on elements of marketing system -products, product differentiation, value addition, pricing, promotion, distribution, and marketing chains. NTFP trade is a common phenomenon in southwest Virginia. The greatest opportunity exists for local level marketing of crafts and specialty wood products. In the case of medicinal and herbal products, very little local value addition takes place within the region, and as a result local market players have little control. Policy interventions are required to enhance the returns to local collectors, which will also contribute to sustainable management of forest resources.

ISSN:1054-9811    

DOI:10.1300/J091v11n03_02

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This study was conducted in rural central and northern Malawi to (1) identify factors limiting/enhancing agroforestry adoption and (2) assess the impact of cultural differences on the adoption and use of agroforestry systems. The study involved interviewing representatives of a large number households concentrated in four separate study areas. The study used the grounded theory method of sociology, which relies on largely qualitative data and inductive reasoning.

ISSN:1054-9811    

DOI:10.1300/J091v11n03_03

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

From January 1992 to December 1994 we investigated the litter production and nutrient cycling behavior ofBambusa bambosplantations of different ages. The annual litter production was 15.4 t ha▭ 1, 17 t ha▭ 1, and 20.3 t ha▭ 1in 4-, 5- and 6-year-old plantations. Litter production was significantly higher compared to other plantations of similar age. Litter fall had a bimodel pattern with a principal peak in the winter and another in the late summer in all ages. Of the total annual litter production, leaf-litter accounted for 58% and twig-litter 42%. With regards to nutrients, the highest concentration of N, P, Ca and Mg was in leaf litter. On an annual basis, 120, 10, 101, 60 and 66 kg/ha (4 year), 141, 13, 121, 72 and 79 kg/ha (5 year) and 184, 16, 183, 91 and 96 kg/ha (6 year) of N, P, K, Ca and Mg were returned through litter fall. The maximum amount of all nutrients was returned through leaf-litter and lowest amount through twig-litter.

ISSN:1054-9811    

DOI:10.1300/J091v11n03_04

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Mineralization is the dominant process controlling soil-solution P in the Spodosols of the southeastern United States. Pine trees growing in these soils are typically colonized by ectomycorrhizal (EM) fungi that are known to produce phosphatases. Little, however, is known of the dynamics of EM short roots or phosphatase activity in tree plantations. To address this question, short root densities, EM morphotypes, and associated surface acid phosphomonoesterase in a 12-year-oldPinus elliottiiplantation in northern Florida were evaluated. The density of total (living and dead) short roots changed little from February through June, with a mean of 7.6 cm3soil. The majority of the short roots, however, were inactive or dead with only 14 to 38% appearing viable upon visual inspection. The majority of the viable short roots were mycorrhizal. The most abundant morphotypes were formed byCenococcumandThelephorabut these had low phosphatase activity. In contrast, less frequently observed morphotypes had substantially higher rates of enzyme production and these may play an important role in sustainable P nutrition of plantation trees.

ISSN:1054-9811    

DOI:10.1300/J091v11n03_05

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

On fragmented forest lands, ecosystem or landscape management approaches must cut across multiple ownerships. Therefore, communication and joint planning between neighboring landowners may be necessary for successful implementation of ecosystem management. This study examines landowners' interest in, and attitude toward, ecosystem management. Specifically, we use a survey and logistic regression model to explain landowner interest in joint planning as a proxy for their interest in ecosystem management. Survey results show that almost 70% of the landowners are interested in joint planning. However, most landowners require certain conditions be met before they would participate. Variables pertaining to attitudes and beliefs about ecosystem management or property rights, and receiving incentives for cooperation across the landscape are more important than demographic, land management, or spatial characteristics in explaining landowners' interest in joint planning. Landowners who believe in managing forests for environmental, wildlife and water quality as well as timber are more likely to be interested. The primary concern of those interested in joint planning is the impact it may have on their timber and/or land values. Planners who develop ecosystem management approaches that involve landowner cooperation should make the environmental impacts and benefits clear, and ensure that it will not reduce land and timber values.

ISSN:1054-9811    

DOI:10.1300/J091v11n03_06

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Single-tree selection logging will likely result in a 4.3% loss in the relative abundance and a 4.1% loss in basal area of trees of commercial species in one cutting cycle due to their removal by harvesting combined with their potential recolonization of only 31% of logging gaps in a Bolivian tropical dry forest. Densities of the most valuable species,Amburana cearensisandCedrela fissilis, were particularly reduced by logging. To sustain the current harvesting rate, uses need to be developed for more non-commercial species and/or silvicul-tural treatments employed that increase regeneration of commercial species and remove non-commercial species using timber stand improvement techniques.

ISSN:1054-9811    

DOI:10.1300/J091v11n03_07

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

TIMBER: STRUCTURE, PROPERTIES, CONVERSION AND USE. 7TH EDITION. Desch, H. E. and J. M. Dinwoodie.1996. The Ha-worth Press, Inc., Binghampton, NY. Reviewed by Graeme P. Berlyn.

ISSN:1054-9811    

DOI:10.1300/J091v11n03_08

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor