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Climate change is one of the greatest environmental, social and economic challenges of our days and warming of the climate system is unequivocal. Greenhouse gases (GHG) emissions caused by human activities are the most significant driver of the observed climate changes since the mid- 20th century. Managed nutrient rich organic soils are one of the largest key sources of GHG emissions in Boreal and Temperate cool and Moist (TCM) climate regions in Europe. In these regions managed organic soils usually are drained forests and fens or mires that when efficiently drained can increase GHG emissions. The total area of managed organic soils in EU is 34.5 mill. ha (7% of the EU area). Organic soils can have high GHG emission as well as carbon storage potential depending on chosen management strategies. Based on the research and results obtained within the framework of the LIFE program project “Demonstration of climate change mitigation potential of nutrient rich organic soils in Baltic States and Finland” (LIFE OrgBalt), the authors have developed a functional land management model – a tool for sustainable and climate friendly management of nutrient rich organic soils. The model is designed to allow the user to assess the performance of organic soils depending on the planned land use type (scenario), based on the land use performance criteria: financial return, economic return, financial deficit and the optimal amount of public funding, reduction of GHG emissions and ecosystem services assessment. Based on the findings and using the developed model, it is possible to implement deliberative management decisions of managed nutrient rich organic soils, to evaluate potential management costs, plan the expected financial return, assess the benefits of climate mitigation and take into account nature values. [ABSTRACT FROM AUTHOR]

Latvia is one of the leaders in production and use of forest biofuel in Europe. The rapid increase of forest biofuel market raises questions about sustainability of the supply chains and contribution of the forest biofuel produced in Latvia to the climate change mitigation. Sustainability of forest biofuel is addressed in multiple recent international political initiatives; particularly, the European 2030 climate and energy package and the nature restoration regulation. Climate change mitigation potential of forest biofuel is surrounded by multiple speculations, which have to be addressed by comprehensive evaluation of greenhouse gas (GHG) emissions due to production and delivery of forest biofuel. According to the study results, average GHG emissions due to delivery of harvesting residues from the state forests correspond to 1.4 kg CO2 eq GJ-1, including forwarding, comminution and delivery to a 68 km distance. This is significantly less than the default values provided in the regulation (EC) 2018/2001, particularly during the delivery of forest biofuel. GHG emissions due to delivery of forest biofuel from removal of vegetation in abandoned farmlands are 1.9 kg CO2 eq GJ-1, from forest drainage ditches - 1.7 kg CO2 eq GJ-1, from pre-commercial thinning - 2.1 kg CO2 eq GJ-1. Estimation of the GHG emissions is complicated by limited information on some of the sources and productivity. Building of the system for collection of activity data is a crucial task for transparent demonstration of GHG emissions and the effect of applied mitigation measures. [ABSTRACT FROM AUTHOR]

A prototype of a mower-chipper typeharvester was developed for cutting small stems in cooperation between LSFRI Silava and SIA Laflora. The prototype produces chips and eco-pellets of various lengths in short rotation coppice, shelter belts and overgrown agricultural lands. The innovative element of the harvester is use of gravity force (bending of stems by a tractor own weight and formation of bunch of shoots with header and underframe) to feed in circular saws and chipper, thus significantly reducing energy demand for bending of shoots into the chipper, which is the most energy demanding operation in other commercial willow harvesters. Time studies were implemented in Skrīveri region in August 2022 in short rotation coppice fields established in 2011. Willows of tree different ages (1, 3 and 5 years) were harvested. The main factor influencing productivity in the study sites was growing stock of the coppice crops. The driving speed of the base machine cannot be significantly increased to avoid clogging of the chipper infeed and to retain good quality of chips; therefore, reduction of growing stock cannot be compensated with faster driving in the field. It was also noted that wood chip quality becomes significantly worse if the stump diameter of an average shoot is less than 1 cm and the saw blades are more often blocked by thin, flexible shoots. Similarly, clogging related issues were found in the 5 year old plantation. Optimal work conditions were in the 3 year old coppice crop; however, the driving speed of the base machine (MTZ82 tractor) was still too high. The recommended speed in such conditions is 0.8-1.2 km·h-1. The yield obtained in the tests under these conditions in the 3 year old coppice crop was 2.4 tons of dry matter per hour. The productivity could be raised by increasing the power of the base machine. There is still space for technical improvements to avoid clogging of material in the chipper and jamming of saw blades, as well as to improve the quality of chips. [ABSTRACT FROM AUTHOR]

The aim of the study is to evaluate greenhouse gas (GHG) fluxes from stems in black alder (Alnus glutinosa (L.) Gaertn.) and birch (Betula pendula Roth) stands with drained and naturally wet nutrient rich peat soils, as well as to evaluate correlation between the GHG fluxes, soil temperature and groundwater level. The study was implemented in 8 forest stands -- three black alder stands with nutrient rich peat soil (stand types according to national classification -- Dryopterioso-caricosa and Filipendulosa) and 5 birch stands with peat soil (stand type Oxalidosa turf. mel. and Dryopterioso-caricosa). Measurement of GHG fluxes was continued for 12 months using Gasmet DX4040 FTIR analyser and removable non-transparent chambers of fixed volume and area. GHG fluxes were measured at 0.5, 1.0 and 1.5 m height on 3 trees in every stand. According to the study results the average CH4 emissions from stem surface in birch stands are 6.9 ± 6.2 g CO2 eq m-2⋅yr-1 and in black alder stands 1.0 ± 3.2 g CO2 eq m-2⋅yr-1. Groundwater level significantly effects CH4 emissions -- if it remains above 15 cm during summer, the CH4 emissions from stem increases to 84.0 ± 25.2 g CO2 eq. m-2⋅yr-1. Tree stems in drained peat soils are not a source of CH4 emissions. According to the study results tree stems in peat soils are not producing N2O emissions. [ABSTRACT FROM AUTHOR]

The study finds out the forest machine operators' opinion about the need for refresher courses, the quality of the courses, the knowledge and skills gained as a result of attending the courses. As part of the research, a questionnaire was compiled and sent to forest machine operators who have attended courses at the Forest Machine Operator Training Center in the last 4 years to improve their professional skills. The questionnaire was prepared and sent electronically at the end of 2021. Within two months, the questionnaire was completed by 147 operators. The aim of the survey is to find out the operators' opinion about attending refresher courses, and whether operators acquire the necessary knowledge and skills in refresher courses, which would increase their productivity. Among the surveyed operators, operators in the age group up to 30 years with work experience on the respective machine under 5 years were more interested in refresher courses, while operators in the age group over 41 years of age having work experience over 5 years were less interested in the refresher courses. It was found that 30% of forwarders and 33% of CTL (Cut-To-Length) harvester operators attend refresher courses on their initiative, while all forwarders operators and 65% of harvester operators attend refresher courses on the initiative of the employer. 75% of forwarder operators and 66% of harvester operators stated that they had acquired additional new knowledge and skills as a result of their training, as a result of which their professional qualification level as well as productivity increased. [ABSTRACT FROM AUTHOR]

Flooded Land is defined as water bodies where human activities have caused changes in the amount of surface area covered by water, typically through water level regulation. Former peat extraction fields are a type of flooded lands which are often mentioned as significant source of greenhouse gas (GHG) emissions. In Latvia, the area of flooded lands in former peat extraction fields is 5.3 kha. The aim of the study is to evaluate GHG emissions from flooded former peat extraction fields to define that the flooded lands are the key source of GHG emissions and approve that further studies are necessary to elaborate country specific emission factors. The study is implemented in three areas in central part of the country, where peat extraction was stopped 25-35 years ago. Measures continued for 12 months, in 9 subplots, each was represented by 3 measurement points. Water and air temperature, as well as water level was measured during the study. According to the study results, flooded areas are a significant source of CO2 emissions (967±107 kg CO2-C ha-1 yr-1); however, the most significant agent of GHG emissions in flooded areas is methane (CH4) - 435±98 kg CH4-C kg ha-1 yr-1. Flooded areas are not significant source of nitrous oxide (N2O) emissions. The net emissions from flooded areas are 18.1±3.7 tons CO2 eq ha-1 yr-1. According to the study results, flooded lands are a significant (one of the largest) source of emissions, and further studies are necessary to improve GHG modelling solutions and activity data. [ABSTRACT FROM AUTHOR]