With an occurring shift in the tree species distribution, European beech (Fagus sylvatica L.) is becoming a perspective for forestry in the Baltics and Latvia in particular, despite presumed occurrence outside the natural distribution range. In 2023, a survey of European beech plantations established in 2020 in the central region of Latvia revealed that 13% of saplings had decline symptoms-branch dieback and top dieback in beech saplings, often accompanied by browning of leaves. An endophytic and anthracnose-causing ascomycete, Apiognomonia errabunda, was isolated from shoots of symptomatic beech saplings and potentially associated with the observed symptoms. Accordingly, this is the first molecularly approved report of this fungus in Latvia.

The European beech ( Fagus sylvatica L.) is increasingly valued in Central and Northern Europe due to climate change. This study assesses the impact of container size on F. sylvatica seedling quality, focusing on growth metrics like height, stem diameter, root-to-shoot ratio in a controlled nursery setting. Using a randomized design, seedlings in various container sizes were evaluated, revealing that larger containers supported stronger root development and balanced growth, whereas smaller containers limited root expansion, impacting long-term potential. Statistical analyses confirmed significant effects of container size on growth indicators, providing insights for nursery practices. Container size, especially dept, significantly improve the quality of seedlings - best results reached by containers HV400, 56% of vigorous healthy seedlings no any damages and no dried seedlings. Future research should examine field performance post-transplantation to validate these results under natural conditions.

This study investigates the soil organic carbon (SOC) and whole tree biomass carbon (C), soil bulk density (BD) as well as changes in these parameters in afforested areas in Latvia. The study covered 24 research sites in afforested areas—juvenile forest stands dominated by Scots pine, Norway spruce and Silver birch. The initial measurements were conducted in 2012 and repeated in 2021. The results show that afforestation mostly leads to a general decrease in soil BD and SOC stock in 0–40 cm soil layer and an increase in C stock in tree biomass across afforested areas with various tree species, soil types, and former land uses. The physical and chemical properties of the soil could explain the differences in changes in soil BD and SOC caused by afforestation, as well as the impact of past land use may have persisted. When comparing the changes in SOC stock with the increase in C stock in tree biomass due to afforestation, taking into account the decrease in soil BD and the resulting elevation of soil surface level, the afforested areas at juvenile development stage can be considered a net C sink.

The climate in Latvia is influenced both by maritime and continental air intrusions. The cherries in continental regions used to be under the threat of prolonged low temperatures but in the maritime regions - of temperature fluctuations. The interest has arisen to grow local sweet cherries in the agroforestry system, and after initial evaluation, eight accessions with a large and healthy trunk, dominant apex, sparse branching, and stable fruit production were selected. The research aimed to evaluate the cold tolerance of the selected accessions compared to the cultivars 'Bryanskaya Rozovaya' (Russia) and 'Meelika' (Estonia). The annual and biannual shoots, spurs and flower buds were evaluated visually in the natural conditions and after artificial freezing at -20, -25 and -30 degrees C in the middle of winter dormancy; and at 10, -15 and -20 degrees C at the end of winter dormancy. They were evaluated visually on a scale from 0 (no visible changes of cross-section) to 5 (cross-section is completely brown); the percentage of damaged flower buds was calculated. Additionally, the analysis of relative electrolyte leakage (REL) was done for annual shoots. The accessions differed in their response to low temperatures and the results indicated various possible patterns of the acclimation and re-acclimation. In general, the accessions from Latvian continental regions had significantly less damaged flower buds, less browned spurs and lower REL of annual shoots during the middle of winter dormancy. One of them, 'Smiltenes 9' stands out with high cold tolerance of the shoots and spurs and acceptable intact flower bud proportion after the freezing at -30 degrees C. In the March, at the end of dormancy, shoots of the accessions from Latvian continental regions still showed lower REL in natural conditions indicating the slower overcoming of dormancy. The accessions from maritime regions had a decrease of REL after the freezing at -15 or -20 degrees C indicating re-acclimation to low temperature.

We investigated the wood fungal community composition in stems of living Norway spruce (Picea abies (L.) Karst.) trees in 20-40 year-old forest stands from Latvia that differed in recent management history (stands with or without thinning) and former land use (former agricultural or former forest lands). Fungal internal transcribed spacer (ITS2) amplicons of DNA extracted from wood were sequenced to assess wood fungal communities. Alternaria, Ascocoryne, Didymella, Heterobasidion, Ophiostoma, Orbilia, Pesotum, Phoma and Pseudocercosporella were the dominant wood pathogen and wood saprotroph genera in the analysed samples. PERMANOVA analysis identified some differences in fungal communities among site types analysed (p < 0.001); tree height and presence/absence of rot in the wood samples (mainly Heterobasidion rot) significantly influenced fungal community composition (p < 0.001). Significant negative co-occurrence (p < 0.05) was observed between Heterobasidion and Ascocoryne genera indicating the differing wood colonizing niches of these taxa. Both stand level factors, such as management history and former land use, and tree level parameters are significant for wood inhabiting fungal communities of living spruces.

Interest in agroforestry as land use practice continues to revive due to it's social, economic, and especially environmental and climate change mitigation benefits. This article encompasses results of productivity of hemiboreal agroforestry system combining rows of wild cherry and small-leaved lime with perennial grasses ( Phalaris arundinacea L. and Festulolium pabulare ) and legumes ( Galega orientalis Lam.). Experimental plot of agroforestry system was established in agricultural land on mineral soil in central part of Latvia in the spring of 2011. Different fertilizers such as by-products of bioenergy production (wood ash, digestate), municipal waste (wastewater sludge) and mineral fertilizers were used to compensate nutrients in the soil and soil buffer capacity. Survival rate of the trees (especially for wild cherry) in agroforestry systems was relatively very low, mostly due to winter frosts and later browsing by hares. Nevertheless, results of our study highlighted that both used fertilizers and interactions between trees and herbaceous plants impact total productivity of system including tree growth, yields of biomass and seeds of herbaceous plants as well as chemical composition of biomass of herbaceous plants. Whereas obtained biomass of herbaceous plants can be used for both forage and energy production purposes, the benefits and risks of fertilization must be assessed on a case-by-case basis depending on the intended use of biomass.

Sweet cherry Prunus avium L. cultivated for wood production is selected and bred mainly based on its growth rate and stem properties to maximize the valuable timber outcome. However, the fruit of sweet cherry has ecological value as food source for animals and can also serve as an income source prior felling. It could be beneficial to consider fruit properties in selection and breeding of cherries for wood production purpose. In this study, we compare the properties, such as volume and moisture content, of fruit collected from cherry orchard and two plantations, where sweet cherry is cultivated for wood production. Based on fruit and trunk properties we select genotypes from cherry orchard, that are promising for further studies and development of locally sourced planting material. Fruit of ten genotypes cultivated for fruit and nine genotypes cultivated for wood was collected in July, 2020. Fruit was then scanned to calculate volume, pitted, weighted and oven dried to obtain dry matter and moisture content. The results show that fruit cultivated in orchard have greater volume and weight, as well as have more pulp compared to genotypes selected for wood production. The relative moisture and dry matter content of the pulp does not follow the same trend, and is not directly associated with morphological properties. Based on fruit size, moisture content and trunk diameter ‘Kazdangas’, ‘Agrais Lielajiem Ķiršiem’, ‘Brjanskaja Rozovaja’ and ‘Muiža’ are the most promising genotypes for further studies aimed to develop planting material with good fruit yield and timber outcomes.

The main goal of this review was to provide an assessment of the potential of fast-growing tree species for the suitable transformation of agroforestry areas for biomass production in the Baltic Sea region. Our interest was to highlight the research on the management process of agroforestry zones by establishing short rotation plantations with the tree species Salix spp., Populus spp. and Alnus spp. to explore the prospects of planning these zones as biomass producers. Short rotation forestry (SRF) with trees whose rotation period is 15 to 30 years, depending on the species, is the most suitable approach for management of these agroforestry zones. Willows (Salix spp.) and poplars (Populus spp.) are suitable for short rotation coppice (SRC), as these tree species can be harvested at much shorter intervals, respectively, 1–5 and 4–10 years, facilitating their use in agricultural systems. The rotation period of Alnus spp. in short rotation plantations for energy wood production is generally assessed to be 15–30 years. The black alder plantations in agroforestry zones are used for sawnwood and firewood production, with a rotation period of 20–40 years. The calculated repayment period of the economic agroforestry zone is about 10–15 years, if 2021 costs and prices are used.

Agricultural land abandonment due to biophysical and socioeconomic constraints is increasing across Europe. Meanwhile there is also an increase in bioenergy demand. This study assessed woody crop performance on several relevant types of marginal agricultural land in Europe, based on field experiments in Latvia, Spain and Ukraine. In Latvia, hybrid aspen was more productive than birch and alder species, and after eight years produced 4.8 Mg ha−1 y−1 on stony soil with sandy loam texture, when best clone and treatment combination was selected. In Spain, Siberian elm produced up to 7.1 Mg ha−1 y−1 on stony, sandy soil with low organic carbon content after three triennial rotations. In Ukraine, willow plantations produced a maximum of 10.8 Mg ha−1 y−1 on a soil with low soil organic carbon after second triennial rotation. The productivity was higher when management practices were optimized specifically to address the limiting factors of a site. Longer rotations and lower biomass yields compared to high-value land can be expected when woody crops are grown on similar marginal agricultural land shown in this study. Future studies should start here and investigate to what extent woody crops can contribute to rural development under these conditions.

The article summarizes the research on managed process of agroforestry zones by short rotation plantations with tree species Salix spp., Populus spp., Alnus spp. and looks at perspectives in the planning of these zones as biomass producers. Short rotation forestry (SRF) with a combination of species and a rotation time of 15 to 30 years, depending on the species used, is the most suitable way for management of these agroforestry zones. Short rotation coppice is suitable for willows (Salix spp.) and poplars (Populus spp.) as these tree species can be harvested at much shorter intervals (SRC), 1–5 and 4–10 years, facilitating their use in agricultural systems. In Alnus spp.short rotation plantation the life cycle for energy wood production is assumed to be 15-30 years. The black alder plantations in agroforestry zones are used for sawnwood and firewood production, with a rotation span of 20–40 years. Calculated economic agroforestry zone repayment period is about 10-15 years, if costs and prices as in 2021 are used.

Abstract The distribution of sweet cherry (Prunus avium L. syn. Cerasus avium Moench.) in natural woodlands of Latvia was studied. The growth, vitality and stem quality of the first-generation plantations established in Latvia in different agricultural soils using the planting stock of local origin was assessed. In woodlands, sweet cherry is found in 11 Forest Resource Monitoring plots in the administrative regions of Madona, Kuldīga, Alsunga, Saldus, Cīrava, and Kazdanga. In the last decade, interest in sweet cherry as a wood producer has increased and plantations with a total area of 21.92 ha were established in 22 localities (Priekule, Kazdanga, Durbe, Talsi, Ventspils, Kuldīga, Tukums, Saldus, Dobele, Bauska, Cēsis, Pārgauja, and Krāslava). Survey was made of sweet cherry plantations established between 1997 and 2019, using both local and foreign origin clonal stock (Danish clone Truust and Swedish clones nos. 9 and 10) in different agricultural soils (typic sod-calcareous soil; sod-podzolic soil; stagnogley sod-podzolic soil) in the districts of Priekule, Kuldīga, Dobele, Bauska, Ķegums, and Smiltene. In plantation forests with optimal growing conditions (typical sod-calcareous soil; pH 6 to 7), 22-year-old sweet cherries of local origin had height (H) of 15.1 m, the diameter at breast hight (DBH) — 16.4 cm and stem volume 157.7 dm3 on average. The maximum H and DBH observed for the largest trees reached 17.6 m and 25.3 cm, respectively. The Danish clone Truust and the Swedish clones nos. 9 and 10 of sweet cherries were promising for growing in Latvian climatic conditions. Selection of perspective clones for establishment of second-generation plantations was made for sweet cherries of local origin.

The chapter summarises the research data on cultivating forest crops in abandoned and marginal farmlands (AL).The course of growth and productivity of different tree species in the local climatic conditions is clarified in a variety of agricultural soils.The research results show the most appropriate tree species for short-rotation or special end-use monoculture or mixed plantations, using Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.), silver birch (Betula pendula Roth.), pedunculate oak (Quercus robur L.), grey alder (Alnus incana (L.) Moench), alder (Alnus glutinosa (L.) Gaertn.),wild cherry (Cerasus avium (L.) Moench syn.Prunus avium), aspen (Populus tremula L.), hybrid aspen (Populus tremula x tremuloides), and small-leaved lime (Tilia cordata Mill.).At the same time, research results show sustainability of management of plantation forests-positive impact on soil agrochemical properties, proportionate changes on above-ground vegetation, and improvement of economic benefits of farmlands.

The establishment of plantation forests in areas not viable for agriculture can make a significant contribution to the economy. The yield from 1 ha of plantation forest depends on the management purpose obtaining of round wood (pulpwood, sawnlog, veneer log, tare), bioenergy and extraction of tree foliage (broadleaved and coniferous). In Latvia, based on 2019 data, plantation forests achieve 2760 ha of Scots pine, 7855 ha of Norway spruce, 7431 ha of Birch, 2123 ha of Grey alder, 1274 ha of Black alder and Populus spp. and 618 ha of Salix spp. Estimated and projected gains are calculated both as round wood over 20 to 50 years: pine - 410-to 994 thou. m3; spruce, - 335 to 2.906 thou. m3, birch - 1.040 -2.452 thou. m3. Accordingly, it is possible to obtain gross income from the whole plantation forest area in Latvia: pine-12.42-63.8 mln. EUR; spruce - 40.1 -192.3 mln. EUR; for birch - 32.2 -202.7 mln. Eur. Additionally to that, 18.6 -21.6 t ha-1 and 24.0 -37.0 t ha-1 of processed foliage can be obtained from 1 ha of pine and spruce forest plantations (40-50 years old). Alnus incana sp. (5-20 years), yielding 19.65-122.65 thou. Solid m3 and Salix spp. (3-5 years), yielding 58.71-84.97 thou. solid m3, are used for energy production, furthermore Alnus spp. wood can be used than valuable raw material for plywood production. At the same time, it is possible to capture 106-1477 thou. tonnes of CO2 equivalent. Systematic investigations of chemical composition of above mentioned Latvian plantation trees, wood and bark, have shown that incorporation of extraction treatment in existing processing schemes will allow to manufacture high value added monomeric and oligomeric products which are of great demand for substitution of synthetic ones in different economy sectors (agriculture, including means for plant protection, food industry, polymer production, pharmacy etc.). Creation of small and medium-sized enterprises in rural region in close proximity to plantations opens the opportunity for the appearance of new working places, including organization of new nurseries, plantation services, private businesses for processing of various lignocellulosic waste into new special products / semi-products / feedstock for green industrial materials and chemicals, at the same time diminishing the logistics expenses.

The largest area of Latvia covered in forests was reached 9 thousand years ago when forests covered 90% of its territory. The rest of the country consisted of swamps and river floodplain meadows. In the warmest post ice age period starting 7000 years ago the temperature was 2.5 °C higher than it is presently. However, 4700 years ago the climate cooled and became dryer: the prevalence of broad-leaved trees decreased while the prevalence of spruces increased. The ratio of trees was also affected by human activities such as the clearance of linden and oak forests, which grow on fertile soils that were favored for agricultural land. In the first period of independence of Latvia (1918–1940) forestation of non-forest land was started to improve the economy: forestation of dunes and planting of alleys for protection against wind. To achieve these tasks, Forest Days introduced in 1930 are held annually to this day. As a result, the forest area increased by 563 thousand ha from 1923 to 2018, reaching 3 383 thousand ha or 52% of the territory of Latvia. Forestry employees and scientists have participated actively in the establishment, evaluation and management of new forest stands as well as suggesting actions for their improvement. The rational use of land was debated in 1990s when 36.6% of agricultural land 42% of forest land became private property as a result of agrarian reform. The contribution of forestry scientists to the improvement of forests include: research on the growth and management of various tree species, research on selection, using the most promising clones and establishing seed plantations, developing technologies for forestation of different soils and dunes. As a result, the technologies for growing planting material have significantly improved. Starting from the collection of seeds to providing planting material for tree plantation and establishment of plantation forests they have provided economic benefits.

Abstract The growth data and the potential returns from 15-year-old plantations of pine Pinus sylvestris L. (6 trial sites), spruce Picea abies Karst L. (9 trial sites) and silver birch Betula pendula Roth (13 trial sites), established in abandoned agricultural lands in a variety of soil types (sod calcareous, anthrosols, podzolic, podzols, gley, podzolic gley, alluvial), using the planting density 2,500 and 3,300 and also 5,000 trees/ha are analysed. For tree plantations in agricultural soils (alluvial sod-gley, gley-sod podzolic, sod-podzolic gley, typic podzol) at the survival of 80-98% the stock volume for 15-year pine is as high as 102-155 m3ha−1 with the volume growth 5.72-8.94 m3ha−1 per year; the same indices for spruce in agricultural soils (gley sod-calcareous, sodpodzolic, cultivated, sod-podzolic gley, alluvial sod-gley, base-unsaturated brown) are 75-98 m3ha−1 and 10.26-15.76 m3ha−1, respectively. For 15-year plantation birch the mentioned indices may vary from 61 to 169 m3ha−1 and from 7.54 to 29.82 m3ha−1 per year. The lowest volume growth (4.66 m3ha−1 per year) is for birch in heavy clay soil (gleyic sod-podzolic), the highest (29.72-29.82 m3ha−1 per year) – in cultivated soils and pseudogley soil. Plantation cultivation of pine, spruce and birch in agricultural lands may by the age of 15 years yield with a profit such forest products as pulpwood, fire wood and woody biomass. The gross income gained from first commercial thinnings of plantation pine, utilizing pulpwood, fire wood and logging residue biomass, may vary from 679-2267 EUR ha−1, for spruce the same indices are 1644-3272 EUR ha−1, for birch - 683-2188 EUR ha−1.

The scope of the study was to evaluate productivity of small size forest machines in early thinning, as well as to identify opportunities to use this technology to Latvia. The study was implemented in Sweden using Vimek 404 T5 harvester and Vimek 610 forwarder. The machines 2 / $ 5 S0 $ % / 0 $ / : 2 /$ 1 / 2 / 0 / operators' experience. Time studies were done by team of researchers from Latvian State forest Research Institute 'Silava'. The study demonstrated that Vimek 404 T5 harvester has considerable advantages in compare to conventional forest machinery to produce limited number of assortments like biofuel or mixture of pulpwood and biofuel in early thinning. Annual capacity of a single harvester working in one shift is 800 ha or 25,000 m 2 00 $% $ : machine is limited – it might not work efficiently in commercial thinning in Latvia due to large number of assortments required by customers, and it has limited possibilities of utilization during seasonal restrictions of forest operations. Productivity of Vimek 610 forwarder is comparable 2$ % $ 1$// $4 : 2 / 2 $ % 1 ss beneficial with increase of forwarding distance. Prime cost of biomass, including harvesting, forwarding and road transport to a 50 km distance is 14.3 EUR m. Hourly cost of Vimek 404 T5 and 610 is similar – 26– 28 EUR h.

The paper describes the potential of producing wood biomass in short rotation tree plantations (rotation period 5, 10 and 15 years) on agricultural lands. The research is focused on managing naturally emerging grey alder (Alnus incana Moench) coppice on agricultural lands, following up its course of growth and estimating the volume of biomass to be recovered. Grey alder as a fast-growing specie is suitable for short-rotation plantation cultivation in sites of nutrient-rich soils (site index H20=12m). Coppice of grey alder between the age of 5 and 15 years may be cultivated as a short-rotation plantation with the biomass yield depending on growing conditions from 20 to 445 loose m(3) ha(-1) and gross income between 189 and 4201 EUR ha(-1). In grey alder plantations of site index H20=12, H20=16 and H20=20 you may already at the age of 10 to 15 years harvest pulpwood (top diameter 7cm under bark), packaging wood and fuel wood; the amount to be obtained depends on the intensity of thinnings done in age class I. As follows from the results, the average volume of fresh biomass in one year-old untended coppice of grey alder varies from 1.43 t ha(-1) to 11.15 t ha(-1) with the mean shoot height Hv=1.4 m and highly variable number of stems per unit area. In two-year old stands this variation is from 5.27 t ha(-1) to 28.50 t ha(-1) with the mean stem height Hv=2.5 in; in three-year old stands from 7.95 t ha(-1) to 36.60 t ha(-1) (mean height Hv=3.0 m); in four-year old stands from 18.83 t ha(-1) to 52.80 t ha(-1) (mean height Hv=4.4 m); in five-year old stands from 22.91 t ha(-1) to 64.23 t ha(-1) (mean height Hv=4.8 m).

Young grey alder stands under 10 years of age that are growing on abandoned agricultural lands in Central Latvian lowlands were selected for this study. In the framework of the research the biomass of the trees was studied and an equation was developed for grey alder stands on abandoned agricultural lands. An allometric equation for the different biomass fractions of grey alder was developed. Tree biomass is characterised by a power model with a single independent variable (DBH), which also indirectly substitutes for the effect of the stand age. The model is adapted to each fraction by changing its ratio values. The determination coefficient of the model is high, varying from R 2 = 0.89 to R 2 = 0.94, and the confidence level of the model is 95%. The biomass of particular fractions is defined by a power regression, with the tree stem diameter at the height of 1.3 m used as an argument. In young grey alder stands on abandoned agricultural lands the majority, 64%, of root fractions is composed of coarse roots, followed by the stump fraction and fine roots, 28% and 8%, respectively. For aboveground biomass the largest fraction is stem, which constitutes 75% of the total aboveground biomass, while the share of branches is 25%.