In Latvia, birch is the second most widespread tree species; the share of birch is higher in private forests. The Forest Research Inventory that was launched in 2004 provides credible and up-to-date information about all forests of Latvia irrespective of the ownership. The data from first three years’ data base of this Project has been used in the present study. The aim of this study was to analyse birch stands in state and private forests concentrating on different aspects: mixture degree, origin of the stand, productivity and quality of the stand. 735 sample plots were selected from the database for the analysis. The proportion of the birch stands in the private forests was slightly higher than in the state forests. There were more mixed stands in the state forests than in the private ones. The standing volume was higher in the mixed stands while the opposite was true for the current annual volume increment of birch. The main regeneration method in both the state and private birch stands was natural regeneration from seed. Artificial regeneration was used only rarely in the private birch stands. The productivity did not differ significantly between the state and private forests; the same was true for the quality, expressed by the outcome of veneer logs. The stand quality differed significantly among site types, being the highest in the forests on dry mineral soils and the lowest in the forests on drained peat soils.

Prolonged summer drought periods are forecasted for the Baltic Sea region during the 21st century, thus increasing the risk of drought stress of saplings used in forest regeneration. Nevertheless, the vitality of young stands might be increased by the selection of suitable planting material. The aim of this study was to estimate the effect of changes in distribution of summer precipitation on height increment, biomass distribution and root morphology of Scots pine and silver birch planting material commonly used in the forest regeneration in Latvia. Containerized pine and bare rooted birch saplings, planted in three different soil types, were subjected to altered distribution of summer precipitation, provided by the use of automated shelter. Sheltered saplings were weekly irrigated with the sum of precipitation of a corresponding period, while afield planted saplings had an unchanged precipitation regime and served as control. Height increment was measured once per week and estimation of morphology of saplings was done after the end of every vegetation season. Significant (p is less than 0.05) differences in height increment, and shoot and root biomass were observed among the same planting material in different irrigation regimes and soil types. In the control plots of peat soil, pine had a significantly (p is less than 0.05) larger height increment while birch-significantly (p is less than 0.05) smaller compared to experiment. Forecasted longer drought periods might reduce the growth of Scots pine in fertile forest types but silver birch growth might be affected in fertile mineral soils in future.

Fire is a major disturbance in hemiboreal forests; it affects not only trees, but also ground vegetation. Previous studies have analysed the succession of ground vegetation after the fire, but not addressed the impact of the size of the burned area on revegetation of it. Therefore, the aim of our study was to assess the differences in post-fire ground vegetation in relation to the distance from the edge of the affected area. Vegetation data were collected using Braun-Blanquet method in three sites (122 sample plots) affected by forest fire and five clearcuts (not affected by fire) (92 plots), all regenerated by Scots pine 6 – 7 years before the assessment. The number of ground vegetation species (in all sites predominantly birds or wind dispersed) as well as their projective cover was not affected by the distance from the nearest edge of burned or clearcut, except in burned sites on dry sand soil (Vaccinosa and Myrtillosa), where herbaceous plant and shrub cover was decreasing (from 23.5% to 11.6%) and bryophyte and lichen cover – increasing (from 3% to 13.9%) with an increasing distance from the edge of the area. The total number of plants in burned areas was twice smaller than in clearcut in the same soil conditions but such large difference in projective cover was not observed. There were no significant differences between burned and clearcut areas in respect to Ellenberg’s indicator values on both soil types, as well as no trend in Ellenberg’s values for soil moisture in relation to distance from the nearest stand edge.

With the increase in demand for renewable energy resources, new studies are carried out about under - utilized resources, namely, stumps. To begin to use stumps in industrial application, it is necessary to find out stump extraction influence on the environment, biodiversity, forest regeneration and other important factors. In Zemgale forestry, Misas and Klīves forest districts managed by Joint stock company “Latvian State Forests” (LSF) study on stump extraction in woodlands where clear-cuttings done in 2006 was carried out in the block No. 177, compartments No. 1 and 5, as well as the block No. 176, compartments No. 3 and 9. In these territories two research objects were made where in November-December 2007 stump extraction as well as soil preparation were performed. Main tasks of the project were to evaluate the results of forest natural seeding and coppice ingrowths in natural regeneration areas and evaluate the use of different methods for artificial reforestation with spruce and pine containerized seedlings. It was observed that more seedlings were cut off in the areas where soil scarification with stump extractor was performed if compared to areas prepared with a disc trencher.

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.

Forest resources are Latvian national treasure that plays an important role in both ecology and economics of Latvia. Although a number of studies give summaries of statistical data, they have also been used as the basis for this study. Therefore, statistical analysis of the data on acquisition, regeneration, import and export of forest resources in Latvia has been carried out in this study. The aim of the study is to identify the available statistical information on the forest resources in Latvia by ascertaining the amount of available information, types of statistical data used in identifying information on tree felling, annual afforestation, import and export, and to carry out analysis of the acquired data. The statistical information has been obtained from the websites of the State Forest Service and the Statistical Office of the European Communities (Eurostat). As a result of the study, we have obtained the dynamics of tree felling and forest regeneration by dominant tree species. The study also reveals the dynamics of import and export of timber resources of the main products. The study was carried out in 2011, in Latvian.

The interest in stumps has increased with recent boost of the bioenergy in Europe. Fuel yield from stumps can be as high as from harvesting residues. The most valuable areas for stump extraction are spruce and pine stands on dry mineral soils. In Finland the utilization of stumps for energy is rapidly moving from the testing phase to forest practice. In 2005 the use of stump wood chips by heating and power plants totalled 0.4 mill. m**3, tripled the consumption of 2004, which corresponds to 14% of the total consumption of forest chips in Finland. Extensive whole-tree harvesting trials in Sweden demonstrate that removal of stumps and slash from clear-felled sites has a strong positive impact on natural forest regeneration. Results from Finland indicate that stump and slash removal can improve productivity and quality of subsequent re-planting of harvested forest sites. The majority of available studies on root rot control demonstrate that subsequent forest regeneration is more successful on sites where the stumps have been removed. The scope of this study was to evaluate quality of forest regeneration after stump extraction in Finland according to the national regulations in Latvia. Number, size, distribution and mortality of seedlings were estimated in 15 compartments. Additionally, moisture and compaction of soils were determined. Results of the study approved that regeneration of forest stands on fertile mineral soils after stump extraction was successful and combination of mounding with scarification during stump extraction provides sufficient growing conditions for new seedlings.

The early stage of forestry is crucial for successful and sustainable forest management. One third of the reforested forest in Latvia is regenerated by planting with different kinds of tree seedlings. The success of forest regeneration by planting depends on correctly prepared soil and choice of the right seedling material. The aim of this study was to evaluate the impact of different soil preparation methods and used type of seedlings on tree survival and growth rate after the first growing season. For this study six young stand sites located in the north-west and central part of Latvia were established in three forest types and in each site soil was prepared in furrows by disc trenching, in mound and left untreated. Reforestation was conducted in the spring of 2017 with four tree species Picea abies, Pinus sylvestris, Alnus glutinosa and Betula pendula and three seedling types were used, bare roots, containerized and improved root system. The evaluation of survival and measure of annual increment was conducted at the end of the first growing season in the autumn of 2017. Results showed that overall the highest seedling survival rate provided soil prepared in mound (90%), and seedlings with improved root system, though the lowest survival rate was observed for bare root seedlings. Containerized seedlings have a higher proportional increment if compared to bare root and improved root system seedlings, but differences are not significant yet (p is greater than 0.05). In conclusion, the survival rate of outplanted seedlings differs by chosen stocktype and soil preparation method used in forest regeneration and for various tree species impact of chosen stock type on survival rate differs.

The analysis of regeneration processes on post-agrogenic lands allows establishing patterns and features of succession processes in phytocenosis, to identify the most appropriate measures to promote natural regeneration and to establish the possibility and feasibility of the production of forestry crops on lands left out of agricultural use. A study of forest regeneration processes in areas of fallow land for agricultural purposes adjacent to the floodplain of the Oredezh River in Gatchina district of Leningrad region. On the prepared study plots (0.25 ha) in different elements of the slope relief, the natural regeneration of pine and spruce and living ground cover was also taken into account. The soils on the objects of the study are agricultural soils of different thickness, from 30 to 45 cm. In two areas the soil is turfy, well-cultivated, concealed podzolic, ferrous illuvial soil on sands. On plots No. 3–5, the soil is turfy, well-cultivated, concealed podzolic, ferrous illuvial, clayey, on a red loam. The purpose of the study was to identify the nature of forest regeneration processes in areas of fallow land for agricultural purposes. It has been established that the composition of the emerging undergrowth depends on a number of factors: the type of soil, the taxation characteristics of the adjacent forest, the forest vegetation subzone, and the living ground cover. In these soil conditions on the deposits, young mixed undergrowth with a predominance of spruce and pine after a meadow stage of ruderal vegetation is formed.

Impact of abiotic (wind, summer drought) and secondary (bark beetle (Scolytinae)) or primary (cervids (Cervidae)) biotic factors affect the survival of Norway spruce (Picea abies (L.) Karst.) that is an economically important tree species. Norway spruce is mostly regenerated via planting – thus with significant investment. Therefore it is important to improve the resistance of Norway spruce stands as much as possible. Aim of the study was to characterize damages in Norway spruce stands by cyclonic wind storm and the regeneration of the stands, destroyed by the storm. Data from 4491 Norway spruce dominated stand, destroyed by the storm of 2005, from State Forest service database were obtained. Areas of post-storm sanitary clearcuts ranged from 0.1 to 7.6, mean 0.9 ± 0.02 ha. Most of the clearcuts were larger than 0.5 ha, demonstrating a relatively large size of gaps created by this natural disturbance. Changes of dominant trees species after the storm were statistically significantly affected by the forest type and type of regeneration. Overall, it happened in 55% of the former Norway spruce areas and was predominantly in cases, where natural regeneration was practiced. No indications of measures to increase stability of future stands against wind damages were found.