Since discovering that signals of random waves submit to the known laws of probability, this became widely used in engineering and energetics for probability distributions analysis of wave height. From an energetic point of view, it is necessary to know the average wave height in, for example, highly wavy (1% probability), medium wavy (25% probability) or non-wavy (95% probability) years. Whereas, maximum multi-year value of wave height characteristics is essential for engineering resistant wave energy converters that could withstand severe marine conditions. Average and maximum annual values of wave height data collected from Klaipėda coastal hydrometeorological station are used for this study. Probability distributions of average and maximum wave heights in the Lithuanian coast are analyzed in this paper. The best fitting is obtained using HYFRAN and EASY FIT software. Both, a test for independence (Wald- Wolfowitz) and stationarity test (Kendall) are carried out for every time series using HYFRAN software. Maximum like hood method is selected for distribution estimation. Fitting is determined using chi-square test and the best fitting is verified with comparison (BIC and AIC) criterion. Fitting for one of the most commonly used distributions in the analysis of wave climate – Rayleigh distribution – cannot be determined with HYFRAN software. For this purpose, EASY FIT software is used additionally. The fit of the distribution is evaluated via the chi-square test similarly. Calculated wave heights based on lognormal probability distribution that fits best according to HYFRAN software are similar to those calculated using Rayleigh probability distribution.

Hydro-physical properties of heavy or presses soil as well as water regime may be improved by various ways, taking into account the texture of soil and climatic conditions. Drainage is the tool for productive farming and economic benefit generation. Hydrological activity of drainage typically depends on project installation quality, anthropogenic and climatic factors. It is important to assess drainage activity under different meteorological conditions. One of methods to improve drainage performance is its installation with thickened humus layer. Lithuanian soil humus layer is close to arable layer and is equal to approximately 20–25 cm. The impact of humus on heavy-textured soil is multiple, since not only moisture regimes, biological activity, sorption capacity, chemical and biological characteristics, stability of plant nutrition are related with its quantity. The dynamics of drainage activity in soil with thickened (up to 40–50 cm) humus layer and with humus layer of natural thickness (20–30 cm) during various seasons of period of 1989–2009 is reviewed. Especially important indicator of drainage functioning – water runoff dynamics. The present article analyses the variation of climatic conditions and drainage runoff in the object. It is determined that the lowest quantity of precipitation in the researched territory during the research period is in spring and winter but the highest – in summer and autumn. During the research period the highest drainage runoff in the field I was during winter season (46.3%), in the field II – in winter and spring almost the same (32–33%).

Sewage sludge is a specific bulky waste and its utilization is hampered by the presence of the environmentally dangerous contaminated substances in the composition presented mainly by heavy metals, pathogens and coagulants. At the same time sewage sludge may serve as a valuable biological raw material. Utilization of the sewage sludge is crucial environmental and economic challenge. Application of the pneumatic pulse method in the technology of dehydration and utilization of the sewage sludge may allow us to speed up the process of drying, reduce power consumption and capital investment, execute process of dehydration at lower temperatures and in less hazardous explosive conditions. Proposed solution is founded on the use of the compact equipment for dehydration and utilization, including pneumatic pulse drying method. For this purpose the pulser – an airflow feeder with required time intervals or pulses, was included in the technological process. In the process of the drying sewage sludge with the use of pneumatic pulse, there is no need to spend all the energy on evaporation of the water molecules and this fact significantly reduces power consumption. Preliminary calculations, taking into account laboratory data, showed that proposed technology of drying sewage sludge allows to reduce power consumption by 25% upon receipt of the dry sludge. The aim of the study is development of sewage sludge dehydration technology for further utilization of design solutions using the pulse method.

Entrepreneurial activity in various regions of Latvia is one of the most actual topics for politicians at many levels. The aim of this paper is to characterize entrepreneurial activity in the Kurzeme Region in the context of municipalities analysing the accessible statistical data. The entrepreneurial activity in the Kurzeme Region is analyzed both in general and in the context of municipalities in this paper. Analyzing accessible statistical data, one can draw a conclusion that the entrepreneurial activity in the Kurzeme Region is not even. It testifies that the factors which influence entrepreneurial activity development in some areas are to be searched at the level of municipalities. In addition, the analysis of data specifies various correlations. For example, the smallest number of merchants per 1000 inhabitants in Kurzeme region is in relatively small border municipalities, but higher results are in large cities and local authorities who comprise larger cities or in municipalities which border with larger towns. It is similarly discovered that in Kurzeme region there is a smaller amount of self-employed persons in local authorities with a large number of merchants per 1000 inhabitants and vice versa. There are also exceptions, further research is necessary to justify such correlations.

In the summer 2010, a study of the below-ground biomass of young (12 - and 14-year-old) Scots pine Pinus sylvestis L. stands was carried out in central Latvia. The fine-root (diameter is less than 2 mm) biomass, tips, length and volume were determined for the mineral soil layer (0 – 60 cm) by core sampling. The main objective was to determine the average fine-root biomass and morphological characteristics in different classes of young stands of Scots pines. The mean fine-root biomass was calculated for the whole stand by using below-ground biomass measurements of different components of sample trees and measurement of the tree stand. The amount of dry fine-root biomass in the soil layer was 5.3 ± 1.6 t haE-1 in the 14-year-old stand and 3.6 ± 1.5 t haE-1 in the 12-year-old stand. The study showed that the largest portion (52%) of the total fine-root biomass of 12 - and 14-year-old Scots pine stands was located at a depth of 0–10 cm, decreasing in deeper mineral soil layers. The average morphological characteristics of fine roots were higher in the older stand. Analysis of the morphology of fine roots showed that at soil depth of 0 – 10 cm the mean root length was 233 ± 44 cm, volume – 1.3 ± 0.6 cm3, value of tips – 537 ± 104 and diameter – 0.7 ± 0.1 mm per 100 cmE-3.

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.