The ability to accurately assess the impact of organic soil drainage on greenhouse gas emissions (GHG) is still limited. Methane (CH4) emissions are characterized by significant variations, and GHG emissions from nutrient-rich organic soil in the region have not been extensively studied. The aim of this study was to assess CH4 and nitrous oxide (N2O) emissions from nutrient-rich organic soil in hemiboreal forests to provide insights into their role in regional GHG balance. Over the course of one year, CH4 and N2O emissions, as well as their affecting factors, were monitored in 31 forest compartments in Latvia in both drained and undrained nutrient-rich organic soils. The sites were selected to include forests of different ages, dominated by silver birch (Betula pendula Roth), Norway spruce (Picea abies (L.) Karsten), and black alder (Alnus glutinosai (L.) Gärtner), as well as clearcuts. Soil GHG emissions were estimated by collecting gas samples using the closed manual chamber method and analyzing these samples with a gas chromatograph. In addition, soil temperature and groundwater level (GW) measurements were conducted during gas sample collection. The mean annual CH4 emissions from drained and undrained soil were −4.6 ± 1.3 and 134.1 ± 134.7 kg CH4 ha−1 year−1, respectively. N2O emissions from undrained soil (4.1 ± 1.4 kg N2O ha−1 year−1) were significantly higher compared to those from drained soil (1.7 ± 0.6 kg N2O ha−1 year−1). In most of the study sites, undrained soil acted as a CH4 sink, with the soil estimated as a mean source of CH4, which was determined by one site where an emission hotspot was evident. The undrained soil acted as a CH4 sink due to the characteristics of GW level fluctuations, during which the vegetation season GW level was below 20 cm.

The study analyses the productivity and costs of compact class forest machines in different types of fellingsanitary felling, thinning, tree plantation, and final felling when sawing undergrowth trees. In accordance with the planned work methods, a productivity forecasting model of harvesting operations has been developed. Productivity and cost are the main challenge in thinning operation, also when a fully-mechanized system is used. The productivity of a harvester significantly affects the costs of mechanized felling, which, in turn, determines if commercial thinning will be profitable. As one of the productivity building areas is the training of operators, the study analyses the effectiveness of training and corresponding productivity changes. The objective of this study is to estimate the productivity and prime cost of roundwood production with Malwa small-sized harvester with a boom length 6 m. The use of small-size machines in different types of felling is possible, if an appropriate work method is used and the diameter of the trees does not exceed the size specified by the manufacturer. The results of the research indicate that it is necessary to choose another technology for sawing seed trees, because the trees are too large for small-size machines. Harvesting productivity depends on dimensions of an average tree. In the diameter class 5.1-9.9 in pre-commercial thinning the productivity was 2.11 m3•h-1, in tending of young stand 1.84 m3•h-1. When working with a small-size harvester, production costs in logging are significantly reduced, if the diameter of extracted trees exceeds 10 cm. The results of the research confirm the appropriateness of the exact technique of thinning. The study results in recommendations of the most efficient methods and development of a productivity predicting model for a small-size wheeled harvester.