Root rot caused by Heterobasidion spp. is one of the most important pathogens in Norway spruce (Picea abies (L.) Karst.) stands in Latvia. It is estimated that in Latvia on average 22.9% of Norway spruce stumps are infected with Heterobasidion spp. The aim of this study was to compare four different electronic devices for Heterobasidion root rot detection in Norway spruce. In the autumn of 2009, in a sample plot located in the forests of Kalsnava district 27 trees were used to compare the possibility of instruments to detect root rot. The results show that IML-RESI F400 accuracy for detecting root rot in Norway spruce is high and the instrument is usable for detecting root rot, but additional accumulators are needed for large sample plots. Rotfinder’s accuracy for detecting root rot varies from probe to probe taken from one tree. Conditiometer AS-1 and Arbo-Sonic decay detector show slightly higher average values for infected trees, but the difference for both instruments between healthy and decayed trees is not significant, thus leaving the usage of instruments questionable.

Small diameter wood obtained from young stand tending, with average d1.3 is greater than 4 cm, is suitable for the production of biofuel. So far mainly hand motorized tools have been used in young stand tending, to gather the small -diameter wood is costly and unprofitable. As the technology evolves and labor costs rise studies are carried out on how to increase the profitability of the young stand tending, by applying mechanized tending and production of biofuel from small-diameter wood. The study analyzed indicators, which directly affect the profitability of biofuel production from small-diameter wood produced by harvester tending. The biofuel production costs are analyzed using average purchase price of wood chips production service paid by JSC ‘Latvijas valsts meži’ (further JSC LVM). Revenue related to sales of chips is analyzed on the basis of JSC LVM average sales price for wood chips. The price of the preparation of the small-diameter wood is high and the proportions of the full cost price of wood chips make up 38%. The price of forwarding service impact on the full cost price comprises up to 25% and depends on the forwarding distance. The profitability calculation shows, that production of wood chips from the harvester tended young stands has to be regarded as unprofitable.

To forecast how different indices describing Latvian forest industry will develop in the future, the decision support program which is based on the research of supply chains and production processes as well as on systematic analysis of the whole industry should be developed. One of the most common types of analysis is modelling of processes. In this paper processes of forestry and wood processing in Latvia are modelled by using general approach for system modelling, and each process is described as an abstract system where only its input and output values were identified. Correlations of input and output value time series with a simple and multiple regression analysis method were analyzed. Regression analysis was created for 77 pairs of indices which theoretically could have significant correlations. Input and output factor linear regression analysis for set of processes Forestry and Wood processing shows that not always there is significant correlation between time series of chosen model factors. Some of correlations between time series of input and output data in the model of forest sector even showed controversial results. The amount of information about processes and their quantitative indicators in Latvian wood processing industry is not sufficient for development of precise simulation models. There is need to develop a list of criteria for missing information and carry out its collection process.

The furniture industry is an innovative industry that produces high added value products and its turnover is several billions of Euros in Europe, and there mainly work small and medium-sized enterprises (abbreviation – SMEs). Nowadays competitiveness is an essential factor for both a country and its enterprises in the process of dealing with changing market conditions. The global market is changing and for enterprises it is too hard to position themselves and find the way how to differ from other competitors. From 2006 until 2010 a Latvian furniture market value, numbers of employees and enterprises in the sector and its share in GDP has decreased. As a result, there are the serious challenges to be met and increase their competitiveness in domestic and export markets. The author has made an in-depth research into influencing competitiveness factors of SME micro level in the furniture manufacturing industry. The study objective was to identify the key internal factors which influence the SME of Latvian furniture manufacturers. The aim was to obtain an internal factor of competitiveness assessment of the 30 respondents by random sampling method and expert method of factor assessment. The enterprises need to constantly increase their competitiveness. The internal factors influencing the competitiveness of SMEs are connected with the products, manufacturing of products, financial situation, management and marketing activities. The competitiveness level of Latvia`s SMEs in the furniture manufacturing has been evaluated as average in 70% of cases. Only 27% of the enterprises show a good level of competitiveness.

Heavy metals are worldwide spread pollutants in soils of functioning as well as abandoned industrial territories, landfills, military areas with its historical contamination, and other sites contaminated by industrial activities. Development of soil and groundwater remediation technologies is a matter of great importance to diminish the hazardous impact of pollution to humans and environment. Sustainable solution can be found for remediation of industrial areas using the stabilization/solidification (S/S) technology, which refers to binding of waste contaminants to a more chemically stable form. Geotechnical properties of soil treated with Portland cement (PC) can be improved when municipal solid waste incineration (MSWI) ash is used as the combined additive. Ash is composed mainly of metals, so environmental impact must be evaluated if it is used as amendment in the cement industry. The use of MSWI ash in stabilization of contaminated soils would be useful for the sustainable environmental management in two ways: S/S contaminated soil gains better geotechnical stability and waste incineration industry gets rid of the ash with high metal content. The aim of research is to provide pilot batch experimental results for leaching of heavy metal compounds when S/S technology is used for contaminated soils using PC and MSWI bottom ash additives. Mineral soils were spiked with copper, PC and MSWI were added in known proportions and leaching tests applied. Main results show that PC addition allows to chemically stabilizing soil; thus, heavy metals are not leached out from combined mass of spiked soil and MSWI bottom ash.

Timber structure is a very complex system with its own specific character that causes a lot of difficulties for designers to predict its precise behaviour under loading. Timber construction behaviour under load is affected by many factors that in most cases influence timber constructions in a negative manner. Part of these influencing factors are properties of material, the other are components of the environment where the timber construction is located. This paper presents the results of experimental research where seventeen softwood (Pinus sylvestris L.) timber beams of rectangular cross section were tested in four point bending under long-term load in uncontrolled microclimate conditions (unheated building, all year round weather in the region of Latvia). Values of mechanical properties (modulus of elasticity), physical properties (density, amount of latewood, number of annual rings in 1 cm of wood) were measured at the start of the test; while monitoring of moisture content of wood, relative humidity and air temperature were performed simultaneously for the whole period of test. It has been observed that the main factors that significantly influence timber beam behaviour during period under load in natural climatic conditions are modulus of elasticity (MoE), density of wood and number of annual rings per 1 cm of wood. Amount of latewood showed an insignificant impact on timber beam behaviour under load.

In this paper regression analysis was adopted to assess the wind-wave relationship between wind speeds and wave heights on the Lithuanian coast of the Baltic Sea. In the coastal observations register missing data of visual wave observations occur because of the fog, ice, evaporation or other meteorological phenomenon. There is also inconsistency in instrumental measurements of wave heights in the Lithuanian coast due to technical issues. First step to fill the gaps in the wave height data is to find a strong relationship between wind speeds and wave heights. In this study correlation coefficients for Nida and Klaipeda coastal hydrometeorological stations data both taking and not taking into consideration wind blowing directions were calculated. Every data set used in this study was treated separately and it was revealed that applying nonlinear regression the most common model for wind-wave relationship analysis on Lithuanian coast is DR-Hill model, while applying multivariable regression it is Full Cubic model. Relationship between wind speeds and wave heights always can be improved by removing swell waves from correlation.

Kriging is a method of interpolation, which predicts unknown values from data observed at known locations. This method uses a variogram to express spatial variation, and it minimizes the error of predicted values which are estimated by spatial distribution. The objective of the current work was to investigate how the accuracy of predicted runoff average depth values ranges by applying ordinary Kriging interpolation method when parameters of the method are altered. The simulation was tested by the following method parameters on: fitted semivariogram model, lag size, neighbouring points; the number of sectors of the circle. The best results of the spatial distribution of runoff average depth were received applying the ordinary Kriging method when the exponential variogram is used, the lag size being 27 km while 6 contiguous points and the orbicular scheme divided into sectors in 45° angle are taken. Applying the Ordinary Kriging method having selected all parameters with probability p = 0.95 the model described about 74% of all investigated values.

Utilization of the sewage sludge is pressing and crucial environmental and economic challenge. High moisture content of the sludge is one of the main difficulties during the process of the sewage sludge utilization. Experimental drying module has been designed and manufactured to identify and verify effectiveness of the main parameters of the thermal drying of the sewage sludge with application of the pneumatic pulse method. The pulser is supposed to be part of the technological scheme in order to speed up the process of drying and saving energy. The pulser supplies hot air into the drying chamber with time intervals by pulse. In the drying chamber the airflow dislodges water molecules from the material by means of pulses and then they are taken away from the drying chamber. For the convenience of the comparison and evaluation of the executed experiment the following general characteristics were selected: drying rate – i – kg minE-1; power consumption – q – kWh kgE-1. The greatest effect in application of the pneumatic pulse method for dehydration of the sewage sludge was achieved at the angle of incidence equal to nearly 90° of the airflow on the dried sample and higher temperature. The experiment showed that application of the pneumatic pulse method for dehydration of the sewage sludge allows to reduce power consumption and speed up the process of drying. The process of drying can be executed at lower temperatures.

The paper presents data on the water quality in drainage from manure-fertilized areas in a large livestock company (629 conditional livestock) from 2008 to 2012. The scheme of investigation consists of two field variants: manure fertilized and non-fertilized. Researches are carried out in drained areas, where the drainage water is drained away through outlets. The nitrogen rate 170 kg haE-1 is used annually to fertilize fields in spring. The aim of the research was to ascertain the impact of large livestock company fields fertilized annually with manure on the water quality in drainage. For the purpose of chemical investigations, water samples from drainage were taken once per month. Water analyses were carried out by the accredited Chemical Analytical Laboratory of the Water Management Engineering Institute of Aleksandras Stulginskis University according to specified methods. Investigation results have demonstrated that fields fertilized annually with manure raised the contents of Nmin and P2O5 in the soil by 1.5 and 2.2 times respectively in comparison to the non-fertilized ones. The increase in these contents was conditioned by the higher air temperature and the lower rainfall. The seasonality of Ntotal concentrations in drainage water was discovered: higher concentrations were identified in autumn and winter, lower concentrations – in spring and summer. Due to low dissolubility in the soil, low Ptotal concentrations were identified in drainage water. The highest concentrations were identified with the start of drainage operation.