This article is covering results of pre-commercial thinning, forest infrastructure and undergrowth harvesting field studies implemented in July, 2007 by Skogforsk and LSFRI Silava. A scope of the study was to estimate prime costs of biofuel production from small trees and to compare two types of harvester heads (Bracke C16.a and Ponsse EH25). The productivity in pre-commercial thinning expressed as trees per E0-h (effective hour) ranged between 53 (Ponsse) and 118 (Bracke) in the pine stand and 150 (Bracke) in the mixed spruce stand. In comparison the LVm3 (LV - loose volume) ranged between 9.9 (Ponsse) and 14.1 (Bracke) in the pine stand and was 13.0 (Bracke) in the mixed spruce stand. In the forest infrastructure (roadside ditches) harvesting productivity was 8.2 LVm3 E0-hE-1 for Ponsse and 12.5 LVm3 E0-hE-1 for Bracke. Productivity was economically insufficient in undergrowth removal, both in harvesting (Bracke) and forwarding (Ponsse) operations, respectively 1.1 and 2.6 LVm3 E0-hE-1. Prime costs of harvesting, forwarding, comminution and chip transport (50 km one direction) in pre-commercial thinning in calculation to LVL LVm-3 were 5.93 for Ponsse and 5.85 for Bracke. Prime costs in forest infrastructure in LVL LVmE-3 were 4.97 (Ponsse) and 6.36 (Bracke). Only Bracke was tested in the undergrowth, where prime costs were 37.55 LVL LVm-3. 'Environmental footprint' of biofuel production from small trees in terms of carbon (C) emissions ranged from 2.6 to 10.2 kg CLVmE-3, including road transport (50 km) to terminal.

Energy transition from the fossil fuel dominating to the one based on renewable energy sources (RES) takes acceleration with the internationally recognised need to stabilise the global warming. Therefore, there is a general consensus that the initiative of the wide use of RES is manifold in its nature making an impact not only on the environmental issues, but also adding to the so desired customer involvement and rural development as well. Rural dimension in reaching the EU targets should arguably be a priority as RES utilisation is decentralised in its nature. Despite the fact that EU with its main strategic documents gives a clear direction on RES utilisation through wider involvement of citizens, especially in rural places, there are certain grounds for stating that a current situation and future insights among EU Member States still differ. Lithuanian case was chosen to explore the sustainability gaps regarding the RES utilisation development in rural places. Literature review is employed to choose the most suitable way aiming to explore and evaluate the RES utilisation development in rural places regarding the sustainability issues. This article adds to understanding and evaluating the main obstacles of the well balanced RES utilisation development in rural places.

To promote the future of abandoned lands management and the reduction of fossil energy consumption in Latvia, the establishment of energy crops plantation facilities, including perennial grasses, was investigated. The objective – suitability of several perennial grasses for bio-energy production under condition of Latvia. The aim of the current research to evaluate the experimental field conditions for the cultivation of perennial grasses. The perennial grasses are modest in terms of soil conditions, they are environmentally friendly, as well as provide high yields of biomass with adequate quality for bio-energy production without large investments. With increasing amounts of bio-energy production the amounts of various by-products which are profitable to utilize as energy crops fertiliser will also increase. It is essential that plant nutrients return back into circulation by creating a complete cycle. In order to test in practice the possibility of creating this complete cycle of growing perennial grasses, an experimental field was chosen at the Research Institute of Agriculture in Skriveri. In the summer of 2011, before trials establishment, the conditions of soil were examined at four depths: 0 – 20 cm; 20 – 40 cm; 40 – 60 cm and 60 – 80 cm. The analyses showed that the experimental field conditions were appropriate for growing of perennial grasses. The results of the soil agrochemical analysis will be a base for future studies of usage efficiency of different fertiliser types on perennial grass productivity and nutrient recycling opportunities in energy crop plantations.

The study represents results of theoretical evaluation of forest biomass available for solid biofuel production in pre-commercial thinning in Latvia. The study is based on the National forest inventory (NFI) data; calculations are done for each NFI plot separately. The calculation is done in three steps – selection of the NFI sample plots, which fulfils criteria for the pre-commercial thinning, development of the diameter distribution table, setting the criteria of the thinning intensity, calculation of extractable biomass. Thinning from below (removal of the smallest trees) is considered in calculation. Two types of biomass are accounted – full tree (aboveground biomass) and stem-wood (stem biomass). The study demonstrates that pre-commercial thinning could become an important source of forest biomass in Latvia (15400 GWh of primary energy according to current situation in forests); however, dimensions of trees and harvesting conditions might be challenging for production. The most of the potential biofuel resources are located in stands with average tree higher than 8 m; therefore, it is reasonably to develop and introduce technologies applicable for production of partially delimbed trees.

Europe’s future wood demand for energy is expected to increase by 10 million to 200 million m3 in the period 2010- 2030. This will be supplied by both domestic sources (forests, industrial residues post-consumer wood waste), but also from sources outside Europe. The EU-28 predicts a near future (2020) gap between solid biomass supply and demand for renewable energy: 21.4 million tonnes of oil equivalents (MTOE). This is estimated via preliminary renewable energy action plans (NREAP’s) per country. The EU-28 expects wood pellet import will merely complete this gap of 21.4 MTOE, with more than 50 million tonnes of pellets. This implies a feedstock need of 125 million m3 of wood from forests and other sources outside the EU-28. A practical approach to include bioenergy in wood sector models should start with the input of wood pellets. Ideally, three types of bioenergy markets should be considered, in which pellets and the other major woody feedstock are included: 1. Large scale power production (the UK, Belgium, the Netherlands, all importing pellets from outside the EU-28); 2. Medium scale combined heat and power (CHP’s) including those in the forest sector (Nordic countries use pellets and chips for energy, merely imported from the EU-28); 3. Small scale residential heating (Germany, Austria and Italy, using wood pellets and logs from regional sources). We suggest starting with inclusion of medium scale CHP’s, followed by large scale power production. Small scale heating is relatively stable and should not have large impacts on future markets.

The most important reason for growing field crops is food consumption. Only some of the total amounts of field crop species are mostly used for cultivation in the largest part of arable land. These crops ensure high economic income. This is the reason why biological diversity has decreased. Crop rotation is considered to be an instrument of sustainable cropping system and this is confirmed again nowadays. Higher cereal yields have been gained by including oil crops or pulses in the rotation. Each field crop has its own calorific value (MJ kgE-1). Grains/seeds and above-ground biomass may have different calorific values because of their chemical composition. Research results from literature confirm that the average net calorific value of winter wheat (Triticum aestivum) and triticale (Triticosecale) grain and straw are ~17 MJ kgE-1, but the net calorific values for oilseed rape (Brassica napus ssp. oleifera) seeds and straw are – 25.70 MJ kgE-1 and 16.37 MJ kgE-1, respectively. Oilseed rape is also known as energy rich crop. It is reported that diversified crop rotations also have greater energetic productivity from above-ground biomass (grain/seed yield and by-products) if compared with crops grown in repeated sowings or in monoculture. Crop rotation in combination with different tillage methods (conventional tillage, reduced or minimum tillage and no-tillage) is the way to improve soil quality, but it is not clear whether the soil treatment method has a significant impact on the overall crop rotational energy productivity.