Planting and tending productivity comparison in mounds and disc trenches using containerized and bareroot coniferous seedlings

ArticleIn 2016 more then 40,300 ha of forest was regenerated in Latvia, where 13,000 ha were seeded or planted and 30,300 ha were left in natural regeneration. Before planting, usually one of two soil preparation methods are used – mounding or disc trenching. In areas with optimal water regime, disc trenching is used, while in wet areas mounding is used. Tree planting and after planting tending is done manually by hand tools. The aim of the study was to compare planting and tending productivity in different soil preparation methods (mounding and disc trenching) by planting different stocktypes (containerized and bareroot seedlings). Planting time studies were done in 12 sites and tending time studies in 8 sites. In planting time studies, different planting operations were measured and compared. In tending time studies, GPS devices were used, where area, distance and working time (productive and rest) was counted from GPS data. Average planting time for containerized seedlings in disc trenches was 10.3 seconds, while in mounds 9.2 seconds per seedling, an 11% improvement. Average planting time for bareroot seedlings in mounds was 28.3 seconds, while in trenches – 18.2 seconds, a 35% improvement. Tending in trenches was done faster than in mounds. On average, one hectare tending time in mounds was 8.4 hours, while in trenches 7.4 hours, an 11% improvement. Walked distance for 1 hectare tending in mounds was 5.4 km, 7% shorter than the distance of 5.0 km in trenches. Factors that influence planting and tending productivity are soil preparation quality, logging residue, and water level on the site. Data from planting and tending time studies could be used for better plan work activities and select suitable planting material for a particular soil preparation method

Evaluation of greenhouse gas emissions and area of organic soils in cropland and grassland in Latvia – integrated National forest inventory data and soil maps approach

ArticleThe aim of the research was to assess distribution of organic soils in farmlands for the time period between 1990 and 2015, as well as to carry out a recalculation of GHG emissions from organic soils in grassland and cropland. We evaluated the area of typical organic soils using digitized soil maps created between 1960s and 1980s there were 183,000 ha of cropland and grassland on organic soils. A selected number of areas on organic soils intersecting with the National forest inventory (NFI) plots were surveyed. We found that 66 ± 10% of surveyed plots still conforms to criteria for organic soils according to Intergovernmental Panel on Climate Change (IPCC) guidelines; in the rest of plots soil organic matter has been mineralized and these areas do not conform to IPCC criteria of organic soils. The following distributionof organic soils was estimated in cropland – 6.3 ± 3.3% in 1990 and 4.1 ± 3.4% in 2015, but in grassland – 11.6 ± 3.6% in 1990 and 7.7 ± 3.9% in 2015. The annual reduction of GHG emissions due to reduction of area of organic soils in cropland in 2015 corresponds to 1,400,000 tonnes CO2 eq. in comparison to 1990 and in grassland – to 1,100,000 tonnes CO2 eq. The estimated reduction of the GHG emissions due to conversion of organic soils into mineral soils, comparing the average value in 2005–2009 with the projection for 2021–2030 on average will correspond to 313,000 tonnes CO2 eq. annually, however LULUCF sector still won’t become a net CO2 sink according to the GHG inventory data on other land use categories and carbon pools

Model for cost calculation and sensitivity analysis of forest operations

ArticleForest operations include logging, off-road and road transport of round wood, harvesting residues and wood chips, soil scarification and pre-commercial thinning, as well as other less conventional operations like stump extraction and undergrowth removal before felling. The process of harvesting can involve different interfering phases with specific productivity parameters, which will have impact on the productivity of harvesting and delivery, as well on the prime cost of logs and forest biofuel. Detailed prime cost calculation allows to assess the impact of various factors on costs of the products, as well as to define threshold values for certain parameters affecting the productivity. The base model elaborated within the COST action FP0902 is complemented with standard economic methods and adopted to the harvesting process or any other forest or farming operation including systems consisting from several machines. The model is designed in a way, which is simple in use, easily extensible with additional parameters and machines and with possibility to change individual input data. The cost calculation section of the model consists from investments (base machines and equipment), labor costs (salaries, social charges, insurance and other payments) and operational costs (fuel, lubricants, maintenance, repair and other consumables). The average hourly cost is calculated according to forecast of number of working hours per year. Engine hours are used in calculation to synchronize input data with service statistics from dealers’ centers. The parameters of the forest stands affecting productivity, like diameter or volume of an average extracted tree, number of relocations per year, average off-road transport distance, driving speed and other parameters are defined in the calculation. Productivity and load size can be set as fixed values or equations (in case if the sensitivity analysis should be done). The model calculates the hourly cost (productive, engine and proposed working hours) and the unit price for each phase of the work process. The sensitivity analysis demonstrates impact of various factors, like number of working hours per year, dimensions of the average extracted tree, forwarding and road transport distance, fuel price and fuel consumption as a default parameters or any other indicator, which can be added to the sensitivity analysis. The model is validated against the actual harvesting contracts and hourly cost of rental machines. Default parameters in the calculation are summaries of information provided by contractors or service companies

Productivity of harwarder Vimek Biocombi in early thinning in Latvia

Во время эксперимента было спилено 17410 деревьев, средний диаметр которых на высоте 1,3 м составлял 3 см, а объем ствола – 0,006 м³. В целом за время рубки ухода было заготовлено и привезено 105 м³ биотоплива. При этом производительность харвардера Vimek на транспортировке лесоматериала в оптимальных условиях не ниже производительности John Deere 810 и аналогичного форвардера среднего класса. Также было установлено, что самая низкая себестоимость (23 € м-3) была у биотоплива, полученного после поздно выполненной рубки ухода, а самая высокая (42 € m-³) – при пилении подроста

Impact of forwarding conditions on productivity of forwarder Kranman Bison 10000

The aim of this study is to investigate potential uses of Kranman Bison 10000 6WD forwarder in thinning under normal and difficult forwarding conditions, to determine productivity, average load size and forwarding costs. In normal forwarding conditions productivity of forwarding increase by 11%. The average forwarded load is 2.0 m³ and the average load capacity is 80%, accordingly. Prime cost of chainsaw-prepared roundwood is 8.7 € mᐨ ³,but, when using harvester for preparing roundwood, itis possible to reduce the prime cost by about 2.9 € mᐨ ³