[en] Aim of study: The study aims to evaluate the maximum potential stocking level in cork oak (Quercus suber L.) woodlands, using the ecologically-based size-density relationship of the self-thinning law. Area of study: The study area refers to cork oak forests in mainland Portugal, distributed along its 18 districts from north to south. Material and Methods: A dataset with a total of 2181 observations regarding pure cork oak stands was collected from the Portuguese Forest Inventory (NFI) databases and from research plots. The dataset was subjected to two filtering procedures, one more restrictive than the other, to select the stands presenting the higher stocking values. The two resulting subsets, with 116 and 36 observations, from 16 and 10 districts of mainland Portugal, respectively, were then used to assess and describe the allometric relationship between tree number and their mean diameter. Main results: The allometric relationship was analysed and modelled using the log transformed variables. A slightly curvilinear trend was identified. Thus, a straight line and a curve were both fitted for comparison purposes. Goodness-of-fit statistics point out for a good performance when the data is set to the uppermost observed stocking values. A self-thinning line for cork oak was projected from the estimated relationship. Research highlights: The self-thinning model can be used as an ecological approach to develop density guidelines for oak woodlands in a scenario of increasing cork demands. The results indicate that the recommendations being applied in Portugal are far below the maximal potential stocking values for the species. It is therefore of the utmost importance to review the traditional silvicultural guidelines and endorse new ones.

[en] Aim of study: We built biomass expansion factors (BCEFs) from Douglas-fir felled trees planted with different planting densities to evaluate the differences according tree size and planting density. Area of study: The Douglas-fir plantation under study is located on the northern coastal chain of Calabria (Tyrrhenian side) south Italy. Materials and methods: We derived tree level BCEFs, relative to crown (BCEFc), to stem (BCEFst = basic density, BD) and total above-ground (BCEFt) from destructive measurements carried out in a Douglas-fir plantation where four study plots were selected according to different planting densities (from 833 to 2500 trees per hectare). The measured BCEFs were regressed against diameter at breast height and total height, planting density, site productivity (SP) and their interactions to test the variation of BCEFs. Analysis of variance (ANOVA) and the post hoc Tukey comparison test were used to test differences in BCEFt, BCEFc and in BD between plots with different planting density. Main results: BCEFs decreased with increasing total height and DBH, but large dispersion measures were obtained for any of the compartments in the analysis. An increasing trend with planting density was found for all the analyzed BCEFs, but together with planting density, BCEFs also resulted dependent upon site productivity. BCEFt average values ranged between 1.40 Mg m-3 in planting density with 833 trees/ha (PD833) to 2.09 Mg m-3 in planting density with 2500 trees/ha (PD2500), which are in the range of IPCC prescribed values for Douglas-fir trees. Research highlights: Our results showed that the application of BCEF to estimate forest biomass in stands with different planting densities should explicitly account for the effect of planting density and site productivity.

[en] This study appraised phyto-remediation efficiency and tolerance mechanism of Juncus effusus as was evidenced by ultrastructural modification in its roots under manganese (Mn) toxicity. Three-week-old J. effusus plants were treated with different concentrations of Mn (50, 100 and 500 M) in hydroponics. Although higher Mn levels caused modifications in growth, biomass, height and root morphological traits, J. effusus tolerated Mn toxicity without showing any obvious phyto-toxic symptoms even under the highest level of Mn (500 M). With incremental Mn levels in the growth media, the plants showed a steady increase in Mn uptake, while translocation factor (TF) for Mn declined. This illustrated the tendency of J. effusus plants to avoid Mn-induced stress by restricting maximum Mn in root tissues. Electron microscopy of root tip cells elucidated plant tolerance mechanism to Mn toxicity. Modification in cellular shape and size, and increased number of vacuoles and mitochondria appeared to play a major role in induction of tolerance against Mn toxicity, and ultimate survival of plant. (author)

[en] The new challenges of modern agriculture to feed the world will rely more and more on science and technological innovation, particularly that derived from 'omics' disciplines, and the speed with which these new techniques will reach the farm.

[en] Some figures are provided, giving an indication the volume of forest resources and timber harvests on the various continents and geographic areas and the size of the populations that live of forests and timber. After highlighting the major developments that have occurred in the last 30 to 40 years, future timber needs are assessed ways of responding to those needs are discussed. (authors)

[en] The scientific work within the activity ''ecological/biological balances and conservation'' is summarised in this report. The aims of the activity during its existence between 1992 and 1994 have been to: (i) arrange a workshop and publish the presentations on the environmental aspects of energy forest cultivations, (ii) perform joint scientific work together with the activity group on ''biological disposal of wastewaters and sludges'', that is closely related to environmental problems, and (iii) produce ecological guidelines concerning energy forestry, suitable for advisers and farmers dealing with bioenergy problems. The most important results from the workshop were the environmental benefits from energy forestry when compared with intensive agriculture and forestry. Energy forestry has positive influence on the carbon balances, nutrient recycling, and soil sustainability. The effects are also positive on the natural flora and fauna, which in most cases are enriched when compared with agricultural crops. From the joint efforts of the two activities the main result was a study tour, conference and workshop, concentrating on biological purification systems. The most promising system seems to be the vegetation filters of short rotation coppice. The report on ecological guidelines contains a number of ideas and recommendations for establishment, management, and harvesting of energy forests in an environmentally acceptable way. It also gives advice on how to locate the stands to minimise the risk of nutrient leakage from arable land. (Author)

[en] Management systems influence soil quality over time. A study was carried out on Van meter farm of the Ohio State University South Centers at Piketon Ohio, USA to evaluate the impact of crop rotations on soil quality from 2002 to 2007. The crop rotations comprised of continuous corn (CC), corn-soybean (CS) and corn-soybean-wheat-cowpea (CSW). Ten soil cores were collected at 0-7.5, 7.5-15, 15-22.5 and 22.5-30 cm, and sieved. The soils were analyzed for total microbial biomass (C/sub mic/), basal respiration (BR) and specific maintenance respiration (qCO/sub 2/) rates as biological quality indicators; total organic carbon (TC), active carbon (AC) and total nitrogen (TN) as chemical quality indicators; and aggregate stability (AS), particulate organic matter (POM) and total porosity (ft) as physical quality parameters at different depths of soil. The inductive additive approach based on the concept of 'higher value of any soil property except ft, a better indicator of soil quality' was used to calculate the biological (SBQ), chemical (SCQ), physical (SPQ) and composite soil quality (SQI) indices. The results showed that crop rotation had significant impact on C/sub mic/, BR, qCO/sub 2/, TC, AC, TN, AS and POM except ft at different depths of soil. The CSW had higher soil quality values than CC and CS. The values of selected soil quality properties under the given crop rotation significantly decreased except ft with increasing soil depth. The SBQ (23%), SCQ (16%), SPQ (7%) and SQI (15%) improved under CSW over time. The results imply that multiple cropping systems could be more effective for maintaining and enhancing soil quality than sole-cropping systems. (author)

[en] One answer to increase wood production is by increasing management intensity on existing timberland, especially in plantation forests. Another is to convert land currently in agriculture to timberland. Short-rotation woody crops can be used in both cases. But, what are the environmental consequences? Short-rotation woody crops can provide a net improvement in environmental quality at both local and global scales. Conversion of agricultural land to short-rotation woody crops can provide the most environmental quality enhancement by reducing erosion, improving soil quality, decreasing runoff, improving groundwater quality, and providing better wildlife habitat. Forest products companies can use increased production from intensively managed short-rotation woody crop systems to offset decreased yield from the portion of their timberland that is managed less intensively, e.g. streamside management zones and other ecologically sensitive or unique areas. At the global scale, use of short-rotation woody crops for bioenergy is part of the solution to reduce greenhouse gases produced by burning fossil fuels. Incorporating short-rotation woody crops into the agricultural landscape also increases storage of carbon in the soil, thus reducing atmospheric concentrations. In addition, use of wood instead of alternatives such as steel, concrete, and plastics generally consumes less energy and produces less greenhouse gases. Cooperative research can be used to achieve energy, fiber, and environmental goals. This paper will highlight several examples of ongoing cooperative research projects that seek to enhance the environmental aspects of short-rotation woody crop systems. Government, industry, and academia are conducting research to study soil quality, use of mill residuals, nutrients in runoff and groundwater, and wildlife use of short-rotation woody crop systems in order to assure the role of short-rotation crops as a sustainable way of meeting society's needs

[en] In discussing the potential contributions of short-rotation forest plantations to the fuel wood supply, a number of economic factors have been considered and analyzed. Very little, however, has been written on the income tax aspects of the subject. The tax treatment of such plantings is an extremely important factor. The federal income tax, in particular, can have a significant impact on production costs and is a major factor in determining the economic feasibility of this type of investment. The major federal Income tax provisions of significance are those that deal with capital expenditures, currently deductible costs and sale receipts. Several alternative tax approaches were available prior to passage of the 1986 Tax Reform Act. The new act's provisions, however, have completely changed the federal income tax treatment of timber income and expenditures, including those associated with short-rotation plantations. This paper analyzes the changes and discusses their economic implications for fuel wood culture

[en] The ''Wood as a Fuel'' programme - which funded the research covered in this report - is one of the renewable energy development programmes managed by ETSU (the Energy Technology Support Unit) for the Department of Trade and Industry. This national programme is developing the production and use of fuel wood from two main sources - forestry residues and short rotation coppice. Wood fuel from short rotation coppice offers the greater potential - energy equivalent to 10 mtce (million tonnes of coal equivalent) could be produced annually from 1 million hectares of land. This programme is now well established, with ten trial coppice sites in operation, plus some 40 others. A number of successfully willow and poplar clones have been selected for different soil conditions, and machinery for planting and harvesting has been developed. Local consortia of farmers and users are being established to provide long-term markets for the wood fuel produced. (author)