Search

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]

European Union (EU) aims to increase the share of renewable energy in total energy consumption in the next decades. The main renewable resource, which is mentioned in the policy documents, is biomass, especially wood biomass. Wood biomass for energy purposes could be successfully acquired from fast-growing woody plantations, growing on non-used agricultural lands. In Latvia, in 2019 were around 250 000 ha non-used agriculture land and part of it could be used for plantation growing. In Latvia, suitable woody species for use in plantations are willow, hybrid aspen, and grey alder. For economic calculations plantation site preparation before planting, planting, management, and biomass harvest costs were calculated, as well as revenues from selling biomass. In total 7 different plantation models were evaluated. Comparing the economic indicators for fast-growing woody crop plantation models during their cultivation and applying a discount rate of 7.63%, average service costs and product selling prices for the period 2015-2019, and under the existing plantation support system in 2021, intensively managed willow plantations, extensively managed willow plantations and hybrid aspen agroforestry plantations show positive accumulated cash flow. Hybrid aspen woody plantations and plantation forest, and grey alder energy wood and woody plantations show a negative accumulated cash flow, and their establishment in 2021 does not pay off. Factors that mostly affect plantation cash flow and therefore economic return are the biomass selling price and harvested biomass volume. [ABSTRACT FROM AUTHOR]

Latvia is one of the largest exporters of pellets in Europe, and at the same time share of biofuel in energy production in Latvia is also one of the largest between the developed countries. Rapid increase of biofuel production and export raises questions about sustainability of forest sector and contribution of the forest biofuel produced in Latvia to the greenhouse gas (GHG) balance in Europe. Sustainability of forest biofuel is broadly discussed issue in Baltic states; particularly, due to continuous increase of production and export of wood pellets. GHG mitigation potential of the forest biofuel is one of the sustainability aspects surrounded by multiple speculations, which has to be addressed by comprehensive comparison of GHG fluxes due to production and use of forest biofuel and substituted fossil fuel. Assessment of the GHG mitigation potential of forest biofuel is complex process requiring multiple activity data and assumptions. Particular complexity of calculation is determined by the need to use harmonized approach for the whole calculation period. The assessment of the climate change mitigation in this study is based on the methods applied in National GHG inventory and literature data on GHG emissions due to production and delivery of substituted fossil fuel and forest biomass including demolition wood. According to the study results substitution effect of the forest biofuel in Latvia continuously increases since 2000, mainly due to export of biofuel, reaching 14323 Gg CO2 eq. in 2020 (by 30% more than the net GHG emissions in Latvia in 2019). Electricity production in pellet factories, in spite of major reduction of GHG emissions in the production process, has minor role in the total substitution effect. [ABSTRACT FROM AUTHOR]

In Latvia peat production is historically important economic sector, giving significant contribution to rural economic development and providing work places in rural areas, where other job opportunities are limited. Every peat extraction field has certain lifespan, based on economic, social or ecological assumptions. Every peat field could be extracted for set period of time, after which peat extraction is not feasible any more. Current legislation in Latvia requires re -cultivating of places, where mineral resources, including peat, were extracted. Aim of the study is to evaluate afforestation as one of the cut -away peatland re-cultivation possibility. Economic analysis were done for extracted peat field afforestation with birch, black alder, grey alder, pine, spruce, hybrid aspen, poplar and willow. The economic calculations were done comparing different timber products from plantations, different planting materials and plantation lifespans. Lowest investment costs for plantation establishment on cutaway peatlands are for pine and spruce plantations and highest for willow plantations. Highest revenues in plantations with 20 years rotation cycle are in poplar plantations with 0.2 m cuttings and lowest in grey alder plantations. In plantations with rotation cycle 40 years highest revenues are in hybrid aspen plantations and lowest in pine plantations. [ABSTRACT FROM AUTHOR]

Aim of the paper is to identify low productivity lands distribution in Vidzeme region, identify enterprises that could use wood chips from willow plantations established on these lands as the main resource in electricity and heat production and calculate produced wood ash amount from these enterprises that could be used as fertilizer and could be recycled in SRC plantations. For better soil fertility evaluation and economic turn predictions all agricultural lands are evaluated in quality units, where one quality unit in money is equal to 5.38 EUR or 70 kg of rye. According to studies, traditional farming in lands, which are below 38 quality units could be unproductive. In Vidzeme region are 501,880 ha of agriculture lands from which 206,574 ha (52%) are lands with quality assessment under 38 units. According to local farmers opinion, the real quality unit, below which economically profitable farming is impossible are 25 quality units. There are 87,900 ha of agricultural lands under 25 quality units, which represent 18% from all agricultural lands in region. These lands could be used by growing SRC plantations in 2013, the region has 48 enterprises that used wood chips, with total amount of 170,500 oven-dried tones per year. Wood chips from SRC plantation could be used in these enterprises. To fulfil the wood chip demand in the region, about 17,000 - 34,000 ha of agricultural land should be planted with SRC plantations. To increase the yields from these lands, fertilization is recommended. In this region are more than 300 enterprises, which use wood as the main resource for electricity or heat production leading to 14,000 oven-dried tons of wood ash production every year. [ABSTRACT FROM AUTHOR]

Short rotation forests (SRF) can be used for biomass production for energy applications in Latvia. Establishment of plantations could be one of possibilities how to reach targets of renewable energy resource (RES) consumption of 40% in 2020. In Latvia's conditions, one of most suitable species that could be used for SRF is willow (Salix sp.). Abandoned agricultural lands are suitable for establishment of plantations. Productivity of 8 oven- dried tons (ODT) ha-1 year-1 can lead to Rate of Return (IRR) of 17.1% and Net Present Value (NPV) 1099 Latvian Lats (LVL) if the biomass price is 33 LVL ODT-1. Establishment, harvesting and transporting costs account for 88% of the total cost of production. Price of wood chip and fuel plays the most important role in economics of plantation. [ABSTRACT FROM AUTHOR]

The aim of the study was to test the suitability of grasses and legume plants for agroforestry systems with fast growing trees under different growth conditions. The current experiment was arranged on Phaeozems / Stagnosols with dominant loam (0--20 cm) and sandy loam (20--80 cm) soil texture by sowing of reed canary grass (Phalaris arundinacea L.), festulolium (xFestulolium Asch., Graebn.) and goosegrass (Galega orientalis Lam.) with 2.5 m wide strips between rows (2.5 x 5 m) of two hybrid aspen (Populus tremuloides x Populus tremula) clones characterized by different productivity. Different fertilizers, namely, waste water sludge (10Tdry ha-1), wood ash (6Tdry ha-1), mineral fertilizers (N25:P50(P2O5):K125(K2O)) for galega and (N60:P50(P2O5):K125(K2O)) for grasses, were applied only on the strips to increase the productivity. The increase of seed yield, biomass of grasses and legumes as well dimensions of trees under all kinds of fertilizers was determined. The first three year's results of yield and economic calculations allowed to make a conclusion that a combination of agriculture caulescent and woody crops helped the growth of trees and led to economic gains either in the second or the third year. Wood ash and waste water sludge as fertilizers were more suitable for reed canary grass and goosegrass, but mineral fertilization was economically reasonable for reed canary grass and festulolium. In case of the lack of fertilization higher income was found from festulolium and goosegrass. [ABSTRACT FROM AUTHOR]

The research aim is to determine the amount of heat energy possible to generate from wood in the main cuttings and improvement cuttings. The following methods have been applied for the research purpose: monographic, logically constructive, and graphic. The research authors basing on the methods developed by scientists from Germany, Denmark, Finland, and Sweden, have calculated the amount of heat energy that Latvia would obtain if utilising timber cutting scraps and firewood, which remain unused in the main and improvement cuttings. The calculations allow concluding that the available firewood resources in 2009 in the main and improvement cuttings equalled to 1672.6 thousand m³, available forestry scraps -- 728.56 thousand m³, tiny saplings -- 376 thousand m³, energy wood obtained from brushwood -- 870 thousand m³, energy wood from roots and stumps -- 652.5 thousand m³. The calculations allowed concluding that in 2009 it was possible to produce heat energy amounting to 6.0 million MWh using energy wood. [ABSTRACT FROM AUTHOR]