[en] Foreword to the Proceedings of the Fores terra Final Conference, which was held in Lisbon, Portugal on 24-26 November 2015. (Author)

[en] It has been estimated that up to 60 million hectares could be devoted to energy crop production in the U.S. Due to economic considerations, biomass crops will probably be produced on marginal cropland which is frequently highly erodible. Thus, the impact of herbaceous and woody biomass crop production on soil erosion must be addressed. Perennial grasses provide year-round soil cover, limiting erosion even with continued biomass harvest. Vigorous perennial herbaceous stands reduce water runoff and sediment loss and favor soil development processes by improving soil organic matter, soil structure and soil water and nutrient-holding capacity. Minimum tillage management of row crops reduces erosion compared with systems involving more frequent or more extensive tillage. Woody biomass plantations reduce water erosion by improving water infiltration, reducing impacts by water droplets, intercepting rain and snow and physically stabilizing soil by their roots and leaf litter. Shelterbelts reduce wind erosion when planted as shelterbelts and improve soil organic matter, soil structure and soil moisture in their leeward zone, reducing soil erodibility. Harvesting of woody biomass plantations may be accompanied by increased erosion. Forestry clear-cutting, especially on steep slopes, often results in a large increase in water erosion. For this reason, it is essential that woody biomass plantations be designed for rotational harvesting, even though this may result in higher harvesting costs. (Author)

[en] Sustainable bioenergy systems are, by definition, embedded in social, economic, and environmental contexts and depend on support of many stakeholders with different perspectives. The resulting complexity constitutes a major barrier to the implementation of bioenergy projects. The goal of this paper is to evaluate the potential of Multi Criteria Analysis (MCA) to facilitate the design and implementation of sustainable bioenergy projects. Four MCA tools (Super Decisions, DecideIT, Decision Lab, NAIADE) are reviewed for their suitability to assess sustainability of bioenergy systems with a special focus on multi-stakeholder inclusion. The MCA tools are applied using data from a multi-stakeholder bioenergy case study in Uganda. Although contributing to only a part of a comprehensive decision process, MCA can assist in overcoming implementation barriers by (i) structuring the problem, (ii) assisting in the identification of the least robust and/or most uncertain components in bioenergy systems and (iii) integrating stakeholders into the decision process. Applying the four MCA tools to a Ugandan case study resulted in a large variability in outcomes. However, social criteria were consistently identified by all tools as being decisive in making a bioelectricity project viable

[en] Aim of the study: The objective of this study is to test the validity of the DBH and total height allometric models fitted to the crown polygon data obtained by the application of a crown delineation and individualisation algorithm which uses the geometrical relationships between the points in the original LiDAR point clouds in the Pinus sylvestris L. stands. Area of study: The study area is located in the province of Álava in the Autonomous Community of the Basque Country. Material and Methods: The crowns are delineated using data from airborne LiDAR point clouds obtained in the 2008 overflight of the Basque Autonomous Community. The DBH and total height data for field trees are obtained from the plots in the 4th National forest inventory. Main Results: For the adjusted total height and DBH models coefficients of determination of 0.87 and 0.74 respectively were obtained. The root mean squared errors were 10.67% and 18.97% respectively. The distributions of obtained DBH and total height fitted values and the distributions of the DBH and total height of the field trees are very similar except for the DBH below 15 cm. Research highlights: For stands of Pinus sylvestris L. in Álava, the geometrical relationships between the points that correspond to laser signal echoes obtained with airborne LiDAR sensors can be used directly to delineate approximations of the horizontal projections of the crowns of the trees. Although the procedure set out here was developed for stands of P. sylvestris L. in Álava, it can be applied to other conifers in regular stands by adjusting the working parameters of the function which delineates the crowns on the basis of the point cloud. (Author)

[en] The perspective by Haberl et al (2013 Environ. Res. Lett. 8 031004) entitled ‘Bioenergy: how much can we expect for 2050?’ is timely and valuable. It deals with an important subject since contrasting views on the subject make it very difficult for policy makers to adopt policies that would allow ‘production and consumption of energy at sustainable levels’, in the words of the authors. It is therefore very important to sort out from the abundant literature on the issue which are the facts and which are the biases and preferences. (perspective)

[en] Aim of the study. Seed production in forest tree species commonly takes a long time due to the length of the juvenile stage. Even though several treatments have been used to induce early flowering in conifer species, experience on their use in subtropical Pinus species is limited. This study aimed to evaluate the effect of GA4/7 dose (0, 1.27 and 2.54 mg cm-2) and application time (July-October), alone or in combination with partial stem girdling, on male and female strobili production in young Pinus patula Schiede ex Schltdl. et Cham. clones. Area of study: Nine clones with different flowering background of high-elevation Pinus patula growing in a six-year old seed orchard established in Central México (Aquixtla, Puebla) at 2,800 m elevation. Material and methods: Two independent flowering trials (FT1 and FT2) were carried out in the seed orchard during the 2009 and 2010 flowering cycles; similar factors were evaluated at both trials but time of application, clones tested, and experimental design used varied for each of them. Partial stem girdling was done at the base of the trunk and the GA4/7 solution was injected into the xylem above the point of girdling. The following spring, the percentage of trees with strobili and the number of strobili per tree were determined for both male and female structures. Main results: Significant differences (p ≤ 0.05) among clones in flowering capacity were found at both trials. None of the treatments applied in FT1 resulted in an increase of strobili formation, most probably because they were applied too late in the growing season. In FT2, however, application of GA4/7 combined with partial stem girdling increased the percentage of trees with strobili and the number of strobili of both sexes, particularly when applied in early July. Partial stem girdling was more effective on promoting male strobili than female ones in gibberellin-treated grafts. Research highlights: Timing of GA4/7 application and stem girdling was important, with a significant interaction with clones tested in FT2 on production of male strobili but not on female strobili. Application of 1.27 mg cm-2 GA4/7 and stem girdling in July promoted the highest percentage of trees with strobili, and increased 25-fold the number of female strobili and 5-fold the number of male strobili per tree as compared to the control treatment. Thus, operational use of this induction treatment would be valuable to increase and accelerate seed production in Pinus patula seed orchards in the region. (Author)

[en] Aim of the study: We analysed the effects of thinning intensity and canopy type on Scots pine growth and stand dynamics in a mixed Scots pine-beech forest. Area of the study: Western Pyrenees. Material and methods: Three thinning intensities were applied in 1999 (0, 20 and 30% basal area removed) and 2009 (0, 20 and 40%) on 9 plots. Within each plot, pure pine and mixed pine-beech patches are distinguished. All pine trees were inventoried in 1999, 2009 and 2014. The effects of treatments on the tree and stand structure variables (density, basal area, stand and tree volume), on the periodic annual increment in basal area and stand and tree volume, and on mortality rates, were analysed using linear mixed effects models. Main Results: The enhancement of tree growth was mainly noticeable after the second thinning. Growth rates following thinning were similar or higher in the moderate than in the severe thinning. Periodic stand volume annual increments were higher in the thinned than in the unthinned plots, but no differences were observed between the thinned treatments. We observed an increase in the differences of the Tree volume annual increment between canopy types (mixed < pure) over time in the unthinned plots, as beech crowns developed. Research highlights: Moderate thinning is suggested as an appropriate forest practice at early pine age in these mixed forests, since it produced higher tree growth rates than the severe thinning and it counteracted the negative effect of beech on pine growth observed in the unthinned plots. (Author)

[en] Sustainable non-food cropping systems for arable land are being studied intensively both in Scandinavia and elsewhere in Europe to find alternatives, in which the need for economic subvention would be lower than the export subsidies for grain or other food products. The area of arable land available for non-food cultivation is about 1 million hectares in Finland and 20 - 30 million hectares in the European Communities. In addition to conventional crops and afforestatation, it is possible to grow energy plants (willow, poplar, miscanthus, etc.) and agrofibre plants in these areas. Cultivation of energy willows or other corresponding plants of less than 5 m in height is usually not considered afforestation, as a willow field can easily be retaken into agricultural use with certain reservations (e.g., covered drains can be clogged) This article gives a survey of the alternatives for the utilization of non-food cropping systems

[en] The aim of the project was to study how total and plant-available contents of Cadmium in the soil are affected by the large amounts of Cadmium that are removed during the harvesting of Salix. Eight long-term Salix plantations, 8-30 years old, were chosen. At each place soil samples were taken in 4 areas in the stands of Salix and in 4 neighbouring areas with comparable soil conditions, but without Salix (reference areas). Cd in three fractions of different bonding strength were determined in the soil samples. The fractions roughly correspond to the total concentration, the exchangeable fraction, and the fraction dissolved in the soil solution. The result showed a relatively minor effect of the Salix plantation on the total concentrations. In six of eight cases, however, the concentrations tended to be lower in the Salix plantations than in the reference areas. When consideration was given to certain pH differences, the exchangeable, and particularly the most soluble fraction, showed a clear tendency for concentrations to be lower in the Salix stands than in the reference areas.The concentrations in stem samples from growing stands were generally lower than those measured in harvest-mature stems in other studies. The concentrations in foliage were of the same magnitude as those in the stems, implying that there is an important return of Cd to the soil at leaf-fall. The negligible effect on the total content in the soil may depend on uptake occurring both in the topsoil and in the subsoil. Re-circulation via the leaves will also result in redistribution of Cd from the subsoil to the topsoil, compensating the uptake from the topsoil. The conclusion reached was that Salix cultivation results in a reduction of the plant-available Cd in the soil, but the effect is not concentrated to the topsoil. 13 refs, 5 tabs, 4 figs

[en] An overview is given of bottlenecks and solutions with regard to Dutch sustainable energy supply policy, focusing on biomass experiments