摘要:

The importance of protecting the genetic heritage of willows and maintainine the eenetic diversitv of both natural and artificial populations isYintr&ced. The devklopment of a set of genetic markers that can immediately be employed in studies of genetic diversity in willows is conciseiy presented: one initial data on the variabilitv within F1 controlled crosses of two willow species that are part of the Canadian willow breeding program are also discussed.

ISSN:1054-9811    

DOI:10.1300/J091v01n03_01

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

No abstract available for this article.

ISSN:1054-9811    

DOI:10.1300/J091v01n03_02

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Short rotation forestry has been investigated since the 1960's. The development of programmes for reseirch in different countries is outlined, analysing the reasons for implementing certain strategies. The driving forces behind the renewed interest in short rotation plantations are assessed. Information has been eathered from short rotation forestry trials in the UK managed by thewwood Supply Research Group, aid similar work overseas, on productivity, biology, costs and logistics of various establishment, management and harvesting systems. In this paper, production strategies are outlined, focusing on recent advances. Models have been developed on a spreadsheet to analyse the economics of production. A sensitivity analysis of the economics involving several variable parameters and different costing methods is presented. The impact of technological developments on delivered wood fuel supply is highlighted. A decision support system which is under development is also outlined.

ISSN:1054-9811    

DOI:10.1300/J091v01n03_03

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Because of their high nutritional content and soil conditioning properties,. municipal and pulp and paper (P&P) sludges-biosolids-can serve as soil amendments for nutritionally deurived or organically soils on forest sites. Studies conducted over the past 20 years at an experimental forest site in Western Washington, USA, have largely confined the potential of biosolids to increase the productivity of many forest lands. These studies clearly demonstrated that application of biosolids at environmentally acceptable rates will result in growth responses for both young seedlings as well as established stands. Municipal biosolids have been applied to a number of different Douglas-fir stands. Young stands applied at 47 Mg ha-1 showed an average of 72%, 14% and 2% height responses for Site Class IV, III and 11, respectively, over a 10 year period. Thinned versus unthinned 55-yeardd Douglas-fir applied with 142 dry Mg ha-l averaged 43% and 48%, respectively, for the 12 year period greater than controls. Average growth responses of 65% and 40% occurred in the 65-year-old stand for the Site Class IV and 11, respectively, from a 47 dry Mg ha1 application. Growth response resulting from application of P&P biosolids to a number of tree species has also been excellent. When properly applied, biosolids can provide an excellent alternaLive to chemical fertilizers as a means of enhancing forest production. Growth response is typically greater and lasts longer when compared to chemical fertilization. Careful consideration has to be made of the site conditions to be certain that environmental risks are minimal and losses through leaching and overland flow will not occur.

ISSN:1054-9811    

DOI:10.1300/J091v01n03_04

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Short rotation forests, consisting of various willows (Salix spp.), are suitable vegetation filters with regard to removal of nutrients from municipal sewage sludge, wastewater, leakage water and bioash (wood ash). As long as contents of heavy metals and known organic compounds are kept below accepted limit values, such waste oducts can be regarded as valuable nutrient resources, and particularly when the vegetation is produced for energy purposes instead of for direct or indirect human consumption. The benefit is three-fold: (i) purification of municipal waste using natural circulation, (ii) production of biomass for energy purposes, (iii) reduction of air pollution when burning wood instead of fossil fuels. Most Salix plantations can be used as recipients of sludge and ash as well as be irrigated with wastewater from sewage plants or with leakage water from dumps. Regarding waste and leakage water irrigation, a combined artificial wetland for winter conditions and a willow vegetation filter during the growing season can be used for the purification The welland should be planted with a suitable vegetation cover, which can be harvested in order to remove maximal amounts of nutrients from the system. This biomass can be used as fuel or in compost. There are also indications that some willow clones are capable of taking up certain heavy metals, while others are not. This is beneficial when growing willow on contaminated soils, which either could be purified or just be used for such plantations.

ISSN:1054-9811    

DOI:10.1300/J091v01n03_05

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This study was conducted to examine the effect of simulated acidic precipitation and aluminum treatment on the growth of Alnus species and the contents of nitrogen fixed by Frankia. The growth and nitrogen contents of Alnus species inoculated with nitrogen-fixing organisms were greater than those of noninoculated Alnus species when treated with simulated acidic precipitation. The nitrogen contents were higher in the soils used for the growth of Alnus glurinosa inoculated with Frankia than in those without Frankia inoculation when treated with either acidic precipitation or aluminum. The-development of root hairs treated with simulated acidic precipitation was poor as lhe pH level decreased, and the injury of A. glurinosa was more severe than that of Alnus hirsuta under scanning electron microscopy (SEM). The growth and nitrogen contents of A. hirsura inoculated with Frankia were greater than those of non-inoculated species and A. glutinosa when treated with aluminum. The leaves of A. glutinosa became yellowish-brown and fell earlier. Under SEM and light microscopy, the surface layer of roots in both Alnus species was injured severely and the number of root hairs decreased as aluminum levels increased.

ISSN:1054-9811    

DOI:10.1300/J091v01n03_06

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The accident at the Chernobyl nuclear power plant in 1986 led to a significant increase of radionuclide content in the eastern part of central Sweden. Radioactive cesium (Cs-134 and Cs-137) have accumulated in the soil, waters and living organisms. In agriculture, farmers are looking for alternative crops also in areas with a high radioactive content. Biomass plantations for energy are potential candidates for such soils provided the cycling of radionuclides can be controlled. Nothing IS known so far about the behaviour of cesium in energy forest production systems. The ability to take up cesium and the distribution of Cs-134 and Cs-137 within plants were investigated in a selected fast-mowing willow clone. kesium-contaminatid soil was used as substrate for apot experiment with cutting-derived plants of Salix viminalis. The total plant uptake of Cs-134 + Cs-137 was approximately 0.2% of the cesium present in the soil substrate. Almost 90% of the assimilated cesium was found allocated to the roots. The total amount of cesium in the plants increased over time.

ISSN:1054-9811    

DOI:10.1300/J091v01n03_07

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Dedicated energy plantations can provide an environmentally benign source of renewable energy as well as serve as an alternative agricultural crop. Special planting configurations may yield additional benefits in terms of a service role between harvests or provide flexibility in the end-use products. By considering multiple benefits obtained from enerery plantings. The overall sustainability of the management system-will be enhanced. Some examples involving shelter plantings, soil stabilization, etc., are discussed as alternatives to single-purpose energy plantations.

ISSN:1054-9811    

DOI:10.1300/J091v01n03_08

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor