It is essential to have information on the tree biomass due to the fact that it is an important ecosystem pool for reporting changes in carbon stocks of forests and increased attempts to diversify the energy sources. In Latvia, comparatively few studies have focused on this topic so far. Our study was conducted on two 36 - 38 years old Norway spruce plantations. Detailed stem analysis of 39 trees was performed, and biomass of the above-ground tree components was determined. We analyzed tree and clone-level biomass distribution, biomass relations with tree dimensions and dependence on the genetic factors. The mean total biomass (kg d.w.) of all analyzed sample trees was 131.4 ± 10.58 kg, the mean biomass of stem 85.9 ± 6.98 kg, the mean biomass of dead branches 8.3 ± 0.82 kg, the mean biomass of living branches 23.5 ± 2.34 kg and the mean biomass of needles 13.7 ± 1.22 kg. On average, 66.1% of biomass was allocated to the stem, 6.4% to the dead branches, 17.4% to the living branches and 10.1% to the needles. The biomass of the analyzed trees positively correlated with all tested tree parameters - DBH, tree height, stem volume. Typically, with increasing tree parameters total biomass and stem biomass increased rapidly but branch and needle biomass increased slowly. Significant differences of tree dimensions were detected between the clones, and the differences in total biomass and stem biomass were clearly correlated with the differences in tree dimensions over clones. No significant impact of the clone was found specifically on the tree biomass or its distribution.

Considering specific role of forest in carbon cycling, the scope of the study is evaluation of assimilation of carbon dioxide in a single grey alder stand. The National statistical forest inventory demonstrates that total area of afforested farmlands is 314 thousands of ha, including 212 thousands of ha are grey alder stands. Empiric data are collected in 2011 in 15 years old grey alder stand representing Aegopodiosa site type, site index II. Dendrometric characteristic of the stand are estimated using a method of 6 sample tree plots. Average height of dominant trees is 9.6 ± 0.14 m, diameter at breast height - 6.7 ± 0.18 cm, volume of stem - 0.02002 ± 0.00673 m3, number of trees per ha – 5806 ± 560, growing stock - 116.2 ± 20.0 m3 haE-1. Density of the grey alder stem wood is 411.0 ± 2.2 kg mE-3, average relative moisture - 51.6 ± 0.13%. Dry biomass of grey alder in the evaluated stand is 73.4 tons haE-1, including stem biomass - 65.3%, branches - 11.1%, leaves - 2.3%, stump - 6.8% and roots - 14.6%. In average evaluated stands accumulated 36.9 tons haE-1 of carbon removing from atmosphere 135.5 t ha-1 of CO2. Wood density is estimated according to ISO 3131:1975 standard, moisture content – according to EN13183-1:2002 standard.

Invention of light weight panel with a trade mark of Dendrolight is one of the most distinguished wood industry innovations of the last decade. At present three layers cellular wood panels have wide non structural application. The aim of the research is to evaluate the bending properties of three layer cellular wood panels for structural application. There were 8 specimens manufactured with thickness 136 or 152 mm, width 300 mm and length 2,500 mm of each of the six horizontal load bearing panel structural models. Scots pine (Pinus sylvestris L.) cellular wood and solid pine wood ribs were used as internal layer of the structural panels. Cellular wood core was placed in horizontal or vertical direction. Scots pine solid wood panels and birch plywood were used as top layer material. Applied glue was polivinilacetate Cascol 3353. The most common stress type in structural subflooring panels is bending; therefore, the influence of the cellular material orientation, ribs and top layer material on the sandwich type structural panel bending strength (MOR) and stiffness (MOE) were evaluated according to LVS EN 408:2011. Extra parameters like moisture content and apparent density were determined. Cellular wood in vertical direction can be used as raw material for structural panel production. Panels with solid timber external layers, with ribs and with vertical orientation of the cellular material showed the highest MOR (35.2 N mmE-2) and MOE (11,500 N mmE-2) values. The influence of the solid wood ribs on the bending properties is directly dependent on external layer material.

The theoretical part of the paper presents an overview of trends in the solution of economic and social problems in rural areas and rural development. It also makes an inventory of modern theories on European rural development and analyses aspects of strategic management of the activities of regional and rural communities. The documentary part of the paper analyses the EU and Lithuanian regional and rural development policy, the developments in the implementation of the EU LEADER programme in Lithuania in 2003 – 2010 and opportunities for its improvement, the establishment of local action groups (LAGs) and their key activities. The empirical part of the paper examines the activities of LAGs in Ukmerge and Radviliskis regions and offers a comparative analysis of the content of five strategies produced by the two LAGs for the period between 2003 and 2013. The research has demonstrated that the five rural development strategies of both LAGs are based on the principles of collaboration among the representatives of local authorities, businesses and rural communities, continuity and consultations with local population. The discussion part focuses on the guidelines for the improvement of the strategic management of rural development. The conclusions present an overview of the typical features, priorities, aims and objectives of the strategies of both LAGs.

The comparison of business and taxation conditions in several countries is one of the main tasks of each investor who claims to start a new business. The same problem is significant for state authorities responsible for attraction of investments as well as for scientists who analyse problems related to investment attraction. The aim of the research is to propose the methodological model to compare taxation conditions of various business forms. The taxation of six different business forms was compared. As the examples for research object, the smallest business forms in Lithuania were chosen: a person having a business certificate, a person engaged in agricultural activity (a farmer), a self-employed person engaged in agricultural activity, a person owner of sole-proprietorship and a person owner of the joint-stock company. In order to compare and evaluate the amount of taxes mathematically, the hypothetical data were taken which allowed to identify the least and the most taxable forms of business in Lithuania. Analysing different business forms and their taxation conditions, the following methods were used: systematic, comparative, logical analysis and synthesis. Legal acts regulating the taxation of each form of organizational business were investigated and summarized. The most difficult conditions for the owners of sole proprietorships in Lithuania were observed in 2010. They had to pay about 50 percent of their incomes. But the best conditions for small business had those people who worked with business certificates. They paid only 6 percent of their incomes.

The negative impact of agricultural pollution with biogenic materials on surface water bodies is a relevant problem. This problem is addressed by limiting or prohibiting certain activities in so called buffer areas. The biogenic materials are carried by surface or groundwater runoff. Water infiltration is influenced by the lithological composition of sediments. Its structure is determined by analyzing geological and geomorphological maps and by drilling boreholes in the selected area. With the help of boreholes the level of groundwater and chemical composition of the infiltrate can be assessed. An installed system of lysimeters and piezometers in the borehole allows monitoring the change of water quality and groundwater level in vertical level of sediments over time. The set of lysimeter boreholes allows to capture and mapping the spatial change of these parameters. This article presents the systematic and practical methodology of drilling the lysimetric boreholes of original construction and using long-term monitoring equipment for water quality.

The aim of the study was to examine the effect of coagulant PAX – 18 (polyaluminum chloride) on additional phosphorus removal in reed sand filters. Batch experiments for precipitation reaction with wastewater from septic tank and after treatment in the reed sand filter were carried out. The doses of coagulant under 200 mg L-E1 and time of coagulation under 72 h were applied. Coagulant PAX – 18 efficiently removes phosphorus from the wastewater. The efficacy of removal depends on the dose of coagulant and the time of coagulation. Optimal hydraulic retention time is about 40 hours. With regard to the consumption of coagulant to remove 1 mg of P, it is most efficient to apply coagulant before wastewater treatment in the filter. During the coagulation time of 40 hours, 1 milligram of aluminium oxide precipitated 0.23 mg of P in the wastewater from the filter and 0.39 mg in the wastewater from the septic tank. In this case the removal of P was 1.65 times more effective. Coagulant decreases the wastewater pollution according to BOD5 and the concentration of suspended solids. Therefore, it is advisable to use the coagulant before wastewater treatment in the filter, as it reduces the organic load of filters and the possibility of filter clogging due to lower concentration of suspended solids.

The article explores the possibility of the vertical filter instead of sand used for more coarse media for recharging, which would reduce the risk of freezing and clogging and ensure the cleaning of wastewater up to the limits. For this purpose the dolomite chippings have been chosen for research. It was equipped with two 0.2 m2 filters area: one of their models was 0.4 m dolomite chippings layer, the other 0.8 m. They have been loaded by the wastewater after the primary cleaning in the septic system. Medium contamination in organic pollutants have been 358 mg O2 LE-1, Ptotal 14.6 mg LE-1, Ntotal 108.5 mg LE-1, suspended solids 161.1 mg LE-1, pH 7.8. Hydraulic load of the filters was 0.03 m3 mE-2 dE-1. Wastewater flowing through a vertical sand layer by an average of 98.2% of the organic pollutants to be detained. The average of effluent wastewater contamination of the filter was 22 mg O2 LE-1. In the filter with dolomite chippings media can be cleaned wastewater with pollution reaches 500 mg O2 LE-1. The maximum load of organic pollutants is 14 mg O2 LE-1. The filtration path length to ensure wastewater cleaning up tolerance 0.8 m. In the filter with dolomite chippings media Ptotal is cleaned even 87.0%, Ntotal only 13.0% efficiency.

In Latvia, Class 1 levelling network crosses major rivers. In the places where the river cannot be crossed over the bridge, the levelling across the river should be done directly. The paper describes the methodology, the applied instruments and the results of levelling performed across the Lielupe and Daugava rivers. The levelling across the Daugava River at the creek, where the length of the sight reaches 700 m, was performed simultaneously with two Ni002 levellers. To facilitate the reading of the levelling rod, across the river, a special scale type mark was constructed and fitted on a levelling rod. It was concluded that for the levelling across up to 200-m-wide rivers, levelling rods with 3-mm-wide stripes can be successfully used. The scale type mark makes significantly easier and speeds up the measurements. Under unfavourable weather conditions, measurements performed across the Daugava at the creek were less accurate. There was no explanation for the difference in the elevations measured by the two instruments; therefore, further careful studies of both levellers are needed.

The change in landscape is a never-ending process. In this article information regarding watermills and small-scale hydroelectric power plants historical development in Latvia has been summarized. The research was conducted from September 2010 till April 2011 with the aim of summarizing information regarding impacts to landscape from changes occurring from 12th century till 21st century. The research had a detailed view about the usage history of the watermills, small-scale hydroelectric power plants buildings, and energy producing constructions. The fundamental changes in energy producing mechanisms and legislation regulations changes that have an impact on river open space landscape and on landscape use in surrounded territories of watermills and small-scale hydroelectric power plants landscape were analyzed and studied carefully. The territories were described and analysed using historical, monographic, and comparative methods. The paper gives possible descriptive historical classification of these industrial landscape elements. The historical progress and legislation evolution until the 21st century has also been summarized.