Economic importance of Silver birch in Latvia has been increasing in last decade, triggering scientific research, dedicated to improvement of this species, including tree breeding. Bulk of progeny trials will reach the evaluation time in next few years; therefore, decisions for further tree breeding activities have to be made. The aim of our study is to evaluate profitability of silver birch breeding, based on current situation in the year 2010 and circumstances in Latvia and assess the factors that might notably influence the result. Analysis considers all available breeding material and links between tree breeding, seed orchards and end product – forest stand, regenerated with improved plants in order to evaluate profitability of different alternatives based on differential approach. Results reveal that differential benefits from forest regeneration with selected birch material in comparison to natural regeneration, in areas with highest site indexes (Ia-II) with 3% interest rate and at least part of the stands managed in order to maximize yield of large diameter trees at age of final felling, are positive. The highest profitability can be reached if selection of best individuals is done based on clonal testing, genetic gain is maximized and combined with proper silvicultural praxis and annual planting area (utilization of seeds from selected trees) are maximized.

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.

The forests in Latvia occupy 49.9% of territory and they have significant economic, ecologic and social functions. The notion ‘forest value’ is frequently understood as the value of wood only but non-wood values are often neglected because there are methodological and practical difficulties to estimate them in monetary terms. The list of forest plant non-wood product (FPNWP) groups potentially important for Latvia was made and the significance of them in Latvia’s national economy was estimated. To obtain the information about FPNWP in Latvia (kinds, amounts, value, own-consumption) the public opinion poll was carried out. 77% of the residents of Latvia aged 18 - 74 have gathered the nature products in Latvia in 2010. The most significant FPNWP are mushrooms, wild berries of family Ericaceae - Vaccinium myrtillus L., Vaccinium vitis-idaea L., Oxycoccus palustris Pers. and birch sap. The contribution of FPNWP in the Latvia’s national economy in 2010 was 66.8 million LVL, including 8.9 million LVL for the products sold in the market or exchanged among households.

The social enterprise features are well known in the world history while in Latvia there is a lack of studies and understanding about it. The aim of the research paper is to study the influencing factors of social entrepreneurship in Latvia. In the research the essence of social entrepreneurship and the main principles for definition of social enterprises – social mission, business orientation and involvement of marginalized groups are described. The analysis to determine the most important internal and external factors influencing development of social entrepreneurship was carried out. It was found out that the main external factors are political and legal environment, lack of knowledge about significance of social entrepreneurship, dominating values in society and such internal factors as access to finances, recruitment of professional and well motivated personnel.

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 paper “Latvian Services Sector Development Model: Internet Solution” addresses an issue of the quality of business environment in the Latvian services sector. In the paper, there are analyzed governmentally supported information systems, data bases and e-services aiming at simplification of B2G communication process, identified their advantages and drawbacks, as well as determined potential for their further development. As a result, a model for optimization of governmental on-line tools, fostering an access to business-related information and fulfilment of administrative procedures in the services sector, has been developed. The paper provides a diversified four-layer solution, which may be progressively realized, depending on the available financial resources.

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.

In 2003 an experimental model of the dairy waste water cleaning facility was equipped for cleaning the wastewater of the milk collection station. We examined the possibilities to destruct the organic pollutants present in the dairy wastewater in the sand filters of vertical and horizontal filtration. The pollution level of the dairy wastewater is from 2 to 4 times higher than that of the domestic wastewater. The dairy wastewater was cleaned following the procedure: cleaning in the aeration-flocculation system-cesspool-two stage sand-reed filter. The pollution of the wastewater leaving the cleaning facility never exceeded the allowable norms. The average BOD5 was 4 mg O2 LE-1 and the maximal value was 9.6 mg O2 LE-1. The investigation revealed that the horizontal sand-reed filter with the filtration path of 7 meters ensured cleaning of the dairy wastewater up to the allowable norms. The organic pollutants were cleaned with the efficiency of 97.2% after filtration through such a sand layer. In order to find out the possibilities of vertical filtration filters use for cleaning the dairy wastewater leaving the milk collection stations, we performed a modelled investigation. The wastewater cleaning efficiency in respect to BOD5 reaches 99.3% in these filters. The calculation according to the regression equation received showed that filtration through 0.6 m sand layer ensured successful cleaning of the wastewater up to the allowable norms. In such a vertical filtration filter the average BOD5 cleaning level was 20 mg O2 LE-1.

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.