Academic staff of higher education institutions has to extend students’ vision and promote their variability of views on competitiveness in order to promote prospective hospitality managers’ competitiveness. The aim and goal of academic activities of the university teaching staff is to search for appropriate or relevant means and provide the necessary conditions to foster the students’ thinking and understanding of the concept of ‘competitiveness’ according to a new paradigm of this notion. The pedagogical experiment was carried out at the Latvia University of Agriculture. The aim of the study was to promote the opinions’ change regarding the notion of prospective hospitality managers’ competitiveness; the developed competitiveness self-assessment method was used as a pedagogical tool. The results of the research (the concluding statistics of the Wilcoxon test and the Sign Test) show that the students’ opinions regarding the notion of prospective hospitality managers’ competitiveness have significantly changed before and after their competitiveness self-assessment. Thus the theoretically grounded method of competitiveness self-assessment approved by students and experts, including a questionnaire of the students’ survey, significantly extended the students’ vision as a pedagogical tool influencing the opinions regarding competitiveness notion among representatives of the prospective hospitality managers’ profession.

Scots pine (Pinus sylvestris L.) is one of the most widespread coniferous species in boreal zones and it has a considerable economic importance in the Baltic countries. The impact of fungi on Scots pine has been known also historically, but it is predicted that it will increase in future due to climate changes that will have a positive effect on incidence and vitality of various species of fungi. The aim of the study was to characterize the occurrence of Lophodermium spp. in young stands of Scots pine in Latvia. Needle samples were collected from young pine stands (aged 1 – 14 years) located in all regions of Latvia. DNA extraction from needles was done using modified CTAB protocol, presence of Lophodermium in total extracted DNA was detected using a PCR method. Meteorological data – air temperature and precipitation – were obtained from all 34 observation stations of the Latvian Environment, Geology and Meteorology Centre. The presence of Lophodermium spp. was detected in all surveyed stands, and occurrence differences between the western and eastern regions were significant (p = 0.004). The occurrence of Lophodermium spp. in the eastern and western regions was affected by the meteorological conditions in autumn and winter of the previous years, as well as differences in the given years’ air temperature and precipitation. In 2016, the eastern region of Latvia had a higher May−August precipitation and, to a lesser extent, temperature, which correlated with a higher occurrence of Lophodermium spp.

The objective of this study is to evaluate the performance of models developed by Repola (2006) to estimate the vertical changes of the basic density of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies [L.] Karst), and birch spp. (mainly Betula pendula Roth) stemwood in the forests of Latvia and to develop a model for the estimation of average knot-free stem density with bark (SD) using diameter at breast height as an independent variable. The study material comprised a total of 81 spruce, 102 pine, and 105 birch stems representing a wide range of tree growing conditions in Latvia and covering all age classes. The knot-free stemwood density (SWD) of pine and birch demonstrate strong vertical dependence along the stem, while for spruce the variation pattern was less pronounced and seemed to be nearly constant along the stem. The SWD estimated by Repola’s models was 4.3% lower for spruce, but 3.4% higher for pine and 2.2% for birch comparing to average values obtained in this study. Sigmoidal regression equations constructed in our study explained 67%, 27% and 54% of variations for predicting SD for pine, spruce and birch, respectively. Birch stemwood has a highest basic SWD – 470 kg mE-3, followed by pine – 397 kg mE-3 and spruce – 385 kg mE-3. According to our results, the birch bark turned to be denser than the birch stemwood, being vice versa for the studied coniferous species.

Yasso07 soil carbon model was used to estimate soil carbon balance in dry forest site types (6 site types in total) in Latvia and the results were compared with data from Biosoil2012 soil surveys. Litter input, chemical quality and climatic data are required to run the model. Three different scenarios were used for climate data input – steady climate, climate change + 0.025 °C annually and climate change + 0.05 °C annually. Forest mineral soil is a carbon sink for the whole modelled period - the years of 1990 – 2030. Under steady climate, the average carbon removal is 0.6 t CO2 haE-1 yrE-1, under climate change (+ 0.025 °C) scenario 0.4 t CO2 haE-1 yrE-1, but under climate change (+ 0.05 °C) scenario 0.3 t CO2 haE-1 yrE-1. CO2 removal at the beginning of the period (1990) was 0.35 – 0.38 t CO2 haE-1 yrE-1. Carbon stock modelled with Yasso07 is lower than estimated in Biosoil2012 soil surveys. Differences between modelled and Biosoil2012 results vary from 2 t C haE-1 in the poorest and 41 t CO2 haE-1 in the third poorest site type. Carbon stock modelled with Yasso07 increases from the poorest to the most fertile site type while Biosoil2012 shows an increase from the poorest to the third poorest, and a decrease from the third poorest to the most fertile site type. Underestimation and different trends between Yasso07 and measured carbon stock may be explained by inappropriate equations and models used to estimate non-woody biomass. It is necessary to improve accuracy of input data for non-woody biomass by elaborating national equations and models in order to include Yasso07 in the national GHG inventory.

Urban forests provide ecological and social functions and significantly improve esthetical value of these ecosystems. These forests also function as recreational areas for urban residents. The aim of this study was to assess the influence of understory cutting of different intensity on vegetation and coincidence with Myrtillosa forest type in Mežaparks, Riga. In total nine study sites were established: three sites adjacent to roads where regular undergrowth management is practiced, three adjacent sites to edges of the pathways, where undergrowth management is practiced only occasionally and three adjacent sites to roads where there is no management activity at all. Combined 54 sample plots were created (each sized 10 × 10 m, area 100 m2 ), where vegetation survey was done using Braun-Blanquet method. This study showed that with an increase in the intensity of undergrowth management, in general, the species richness and their coverage increases, or more specifically, the number of herbaceous and moss species increases, but the occurrence of shrub species decreases. In all study sites we observed the development of synantrophic species, especifically, the development of fructification which was indicated by the following species: Sambucus nigra L., Sambucus racemosa L., Amelanchier spicata Lam. If management intensity decreases, the proportion of competitor species decreases, but the proportion of CSR strategy type species stabilizes.

The objective of the research was to characterize the qualitative and quantitative changes in ground and tree vegetation within 10 years since the beginning of observations at Level II forest monitoring plot in Valgunde. Tree height, diameter, stem volume, radial increment, crown condition and cone yield were determined, as well as crown projective cover of each plant species was estimated. To study bioindication, the average Ellenberg’s and Düll’s indicator values for the monitoring plot were estimated. Species composition in the Level II monitoring plot in Valgunde is typical for Myrtillosa forest type – there is a distinct moss layer, in which Hylocomium splendens and Pleurozium schreberi predominate, and Vaccinium myrtillus is the most common in the herb layer. Shrub layer mainly consists of spruce seedlings, and the tree layer – of Scots pine. Changes in vegetation over 10 years are insignificant. It can be explained with no forest management activities occurring within the observation plot, such as logging or fertilization, and it may take a longer time to observe significant changes. Tree stand indicators correspond to the average in Latvia in Myrtillosa type forests, but the tree volume is higher in Valgunde monitoring plot.

The biological control agent Rotstop, composed of spores of Phlebiopsis gigantea, is used for treatment of conifer stumps to reduce the spread of Heterobasidion root rot in commercial forests. Two experiments were conducted to compare the antagonistic ability of the Rotstop isolate and nine Latvian isolates of P. gigantea against root rot fungus Heterobasidion, in wood of Scots pine and Norway spruce. Billets of conifer trees were first sprayed with a spore suspension of P. gigantea and then with Heterobasidion at different concentrations. The presence of fungi in billets was evaluated by morphological characteristics of mycelium. The Latvian isolates of P. gigantea showed similar or even higher values of efficacy against Heterobasidion (average efficacy 84% in spruce and 89% in pine) than the commercially manufactured Finnish preparation Rotstop (61% in spruce and 90% in pine). Latvian isolates of P. gigantea have a potential to be used for preparation of biological control agents in the future.

European beech (Fagus sylvatica L.) timber value is high in southern Europe due to a great demand from Asia. Since the timber market is global, over a long time we can expect gradual increase in demand also in other countries, including Latvia, where climatic conditions becomes increasingly more suitable for this species due to ongoing climatic changes. In order to develop recommendation for the use of beech in our country, the aim of the study was to assess the potential financial gain from Fagus sylvatica stands in Latvia. Assortment structure, defined by topdiameter and length, as well as their prices was set based on the literature survey. Results showed higher income from older (115 years) than form younger (58 years) stands: 9108 EUR haE-1, and 7939 EUR haE-1, respectively. However, the opposite was true for the net present value (r = 3%): 1423 EUR haE-1 and 304 EUR haE-1, respectively.

Surface water runoff, formed in the company areas due to changing wastewater discharge and pollution fluctuations can be treated in retention ponds. Pollutants, released into the ponds, mineralize during complex natural biochemical processes in the aquatic environment. The paper presents the long-term observation data (2004 – 2016 m.) on the purification of surface wastewater, formed in the company’s production territory, in retention ponds. The aim of this work is to identify surface wastewater purification efficiency in retention ponds. Wastewater samples were taken before and after biological treatment. The samples were investigated in the Chemical Analysis Laboratory of the Water Research Institute of Lithuania University of Agriculture. Biochemical oxygen demand (BOD7 ) was determined with titrometric method, suspended solids (SS) – with gravimetric method, having filtered the substance through a mid-thickness filter. Concentrations of oil pollutants were determined with the help of a spectrophotometric device of infrared rays IKAN-1 in the Analytical Department of Agrochemical Study Center of Lithuanian Agricultural Institute. Although the suspended solids, BOD7, and oil hydrocarbon concentrations, released into the natural environment, were below the MAC when they are collected from the company’s production areas, they are often contaminated; therefore, it is necessary to treat them. The purification efficiency of researched materials was satisfactory and reached 61, 64 and 91%.

The plants emit different types of volatile organic compounds (Bio VOC’s) and can improve air quality: they effectively remove organic pollutions and reduce the number of microorganisms in the air by releasing phytoncides. The lack of negative ions in the air can cause deterioration of the health of humans breathing it. At the same time, an air saturated with negative ions can improve the state of health and provide a comfortable environment. In this article, the influence of the plants (Cupressus macrocarpa) on the number of ions is proved, based on a series of experiments performed with applying high-voltage pulses (air ionizer). This work is devoted to the elaboration of the mathematical relationship between the air ions concentration and the factors influencing it. For this purpose an experimental stand was made, consisting of two equal compartments: one contained the plants while another one was used as a control without plants. It was concluded that the plants, in general, are able to stabilize the ion concentration and to reduce its fluctuations. The plants help to increase the concentration of negative ions and to decrease the concentration of positive ones.