Forest Sector Competence Center

Riga, Latvia

Forest Sector Competence Center

Riga, Latvia
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Kaleja S.,Forest Sector Competence Center
Research for Rural Development | Year: 2014

The study represents results of productivity studies of mechanized ditch cleaning using Ponsse Fox harvester adapted to multi-tree handling H6 head in forest drainage systems managed by Joint stock company "Latvia state forests". The aim of the study is to evaluate productivity of extraction of biomass from ditches depending on working method and to estimate factors affecting prime-cost of biofuel in mechanized harvesting. The study results demonstrate that the 2nd method (mechanized extraction of roundwood and following motor-manual cleaning of remaining vegetation) is the most efficient solution for mechanized cleaning of ditches. Benefits of the 2nd method are smaller costs of undergrowth removal and bigger output of solid biofuel. Ponsse Fox harvester demonstrated sufficient work quality and productivity in the trials; however, it would be wise to use heavier harvesters or caterpillar excavator based harvesters in ditch cleaning. Using the 2nd method, a harvester can extract about 227 ha of ditches (23,000 m3) annually.

Adamson K.,Estonian University of Life Sciences | Klavina D.,Latvian State Forest Research Institute Silava | Drenkhan R.,Estonian University of Life Sciences | Gaitnieks T.,Latvian State Forest Research Institute Silava | And 2 more authors.
European Journal of Plant Pathology | Year: 2015

For the northern Baltic region, Diplodia sapinea (Fr.) Fuckel, a well-known around the world pine pathogen, was first recorded in Estonia on Austrian pine (Pinus nigra Arn.) in 2007. Wider monitoring of the fungus was promptly started. Shortly, in 2012, the native Scots pine (P. sylvestris L.) was found symptomatic: first in Estonia, then in Latvia, and in 2013 in north-west Russia. Several individuals of exotic Mountain pine (P. mugo Turra) and some Bosnian pines (Pinus leucodermis Ant.) were also found to be infected. By the end of 2013, the front of the northward enlargement of the range of D. sapinea had reached to central Estonia. Early detection and continuous monitoring of this pathogen on native and introduced ornamental pine species will support forest and green belt management specialists with timely information, if an epidemic, as it occurred previously with the invasive Dothistroma needle blight, would emerge. © 2015, Koninklijke Nederlandse Planteziektenkundige Vereniging.

Klavina D.,Latvian State Forest Research Institute Silava | Klavina D.,University of Latvia | Menkis A.,Swedish University of Agricultural Sciences | Gaitnieks T.,Latvian State Forest Research Institute Silava | And 5 more authors.
Baltic Forestry | Year: 2016

The objective was to investigate the impact of stump removal from clear-cuts on early mycorrhizal colonisation, seedling growth, and chemical properties of soil and needles of replanted Picea abies. The study included three forest types differing in soil conditions: Hylocomiosa (H), Myrtillo-sphagnosa (MS) and Myrtillosa-mel. (MM) forest types. Soil characteristic for H forest type is well-aerated dry podzol, while MS and MM comprise poorly-aerated gleyic, and respectively, wet and drained (dry) podzols. The clear-cuts were made in winter 2010-2011, stump removal accomplished during late spring – early autumn 2011, and the plantations established in April 2012. Prior to planting, each clear-cut was divided into discrete plots, subjected either to stump removal or, alternatively, to traditional soil preparation by disc trenching. After one growing season (in autumn 2012), seedling mycorrhization, shoot and root morphological parameters (length of the shoot, root collar diameter, mass of new roots), and chemical composition of needles and rhizosphere soil were determined. Seedling mycorrhization, chemical composition of needles and soil did not differ significantly between stump removal and trenching plots in any of the forest types. Also richness of mycorrhizal morphotypes and communities of root inhabiting fungi were similar. Fungi commonly detected in forest nurseries dominated fungal communities in roots, among which Thelephora terrestris was the most abundant composing 55.3 %. In each of the forest types, shoot length, root collar diameter and mass of new roots were either higher on stump removal plots or did not differ significantly. The only exception in this respect was the higher shoot height observed on trenching plots in H forest type. In conclusion, the study demonstrated that after one growing season stump removal has low or no impact on communities of mycorrhizal (and other soil) fungi, and performance of replanted P. abies seedlings on podzols with different mechanical composition, aeration and moisture. © 2016, Lietuvos Misku Institutas. All rights reserved.

Lazdins A.,Latvian State forest Research Institute Silava | Prindulis U.,Latvian State forest Research Institute Silava | Kaleja S.,Latvian State forest Research Institute Silava | Daugaviete M.,Latvian State forest Research Institute Silava | And 2 more authors.
Agronomy Research | Year: 2016

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 were driven by experienced operators; harvesting and forwarding methods were adopted to the 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 m3; however, application of the 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 with the conventional middle size forwarders; however it becomes less 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-3. Hourly cost of Vimek 404 T5 and 610 is similar – 26–28 EUR h-1. © 2016, Eesti Pollumajandusulikool. All rights reserved.

Zimelis A.,Latvian State forest Research Institute Silava | Spalva G.,Latvian State forest Research Institute Silava | Saule G.,Latvian State forest Research Institute Silava | Daugaviete M.,Latvian State forest Research Institute Silava | And 2 more authors.
Agronomy Research | Year: 2016

Forest ditches is one of the poorly utilized sources of biomass for energy production and timber industry. Increase of productivity and reduction of cost of extraction of biomass from the ditches, retaining at the same time high quality standards, are the key issues of mechanization of harvesting operations in this area. The scope of the study was to evaluate productivity and cost of biomass delivered from forest ditches, when tracked excavator based harvester and different work methods are used. New Holland 215B excavator with Ponsse H7 felling head was used in trials. The machine was operated by experienced operators. The study was implemented in drainage systems managed by Joint stock company „Latvia state forests”. Total extracted area 12 ha, extracted biomass – 734 m3. Duration of the study including harvesting and forwarding – 4 months. Average cost of roundwood production including road transport to 50 km distance in the trials was 27 EUR m-3, average cost of biofuel – 11 EUR m-3(4.5 EUR LV m-3). The study approved advantages of excavators in ditch cleaning operations; however, several improvements are possible. The machine should be equipped with smaller accumulating felling head, delimbing and bucking should be done in parallel to a ditch direction, number of assortments should be reduced, as well as extraction of trees with diameter below 6 cm should be avoided. © 2016, Eesti Pollumajandusulikool. All rights reserved.

Gaitnieks T.,Latvian State Forest Research Institute Silava | Gaitnieks T.,Forest Sector Competence Center | Klavina D.,Latvian State Forest Research Institute Silava | Muiznieks I.,University of Latvia | And 4 more authors.
Mycorrhiza | Year: 2016

We examined differences in fine root morphology, mycorrhizal colonisation and root-inhabiting fungal communities between Picea abies individuals infected by Heterobasidion root-rot compared with healthy individuals in four stands on peat soils in Latvia. We hypothesised that decreased tree vitality and alteration in supply of photosynthates belowground due to root-rot infection might lead to changes in fungal communities of tree roots. Plots were established in places where trees were infected and in places where they were healthy. Within each stand, five replicate soil cores with roots were taken to 20 cm depth in each root-rot infected and uninfected plot. Root morphological parameters, mycorrhizal colonisation and associated fungal communities, and soil chemical properties were analysed. In three stands root morphological parameters and in all stands root mycorrhizal colonisation were similar between root-rot infected and uninfected plots. In one stand, there were significant differences in root morphological parameters between root-rot infected versus uninfected plots, but these were likely due to significant differences in soil chemical properties between the plots. Sequencing of the internal transcribed spacer of fungal nuclear rDNA from ectomycorrhizal (ECM) root morphotypes of P. abies revealed the presence of 42 fungal species, among which ECM basidiomycetes Tylospora asterophora (24.6 % of fine roots examined), Amphinema byssoides (14.5 %) and Russula sapinea (9.7 %) were most common. Within each stand, the richness of fungal species and the composition of fungal communities in root-rot infected versus uninfected plots were similar. In conclusion, Heterobasidion root-rot had little or no effect on fine root morphology, mycorrhizal colonisation and composition of fungal communities in fine roots of P. abies growing on peat soils. © 2016 Springer-Verlag Berlin Heidelberg

Klavina D.,Latvian State Forest Research Institute Silava | Menkis A.,Swedish University of Agricultural Sciences | Gaitnieks T.,Latvian State Forest Research Institute Silava | Gaitnieks T.,Forest Sector Competence Center | And 4 more authors.
Scandinavian Journal of Forest Research | Year: 2016

In 2010, dieback of Norway spruce (Picea abies) was observed in Latvia. As mostly stands on seasonally or permanently water-saturated soils were damaged, we hypothesized that the recorded foliar damage might be associated with belowground factors. We established 48 sample plots in stands with damage symptoms for soil parameter evaluation and fine root sampling to determine the number of fine roots in different growth stages and to describe the associated fungal community. Among sample plots on organic soils, there were fewer viable older fine roots and greater number of dead fine roots in more damaged sites than in less damaged. These root parameters were significantly correlated with higher groundwater level and soil pH. The fungal community was dominated by ectomycorrhizal (ECM) species (the most common was Tylospora asterophora), the endophyte Oidiodendron maius and saprotrophic species Cryptococcus magnus. Saprotrophic species had higher abundance in more damaged sites, suggesting a shift in fungal communities from ECM fungi. In conclusion, the results of this work suggest Norway spruce root system response to short-term climatic stress, which should be considered when planning spruce forest management, especially on organic soils with a high groundwater level. © 2015 Taylor & Francis.

Brauners I.,Latvia University of Agriculture | Brauners I.,Latvian State Forest Research Institute Silava | Bruna L.,Forest Sector Competence Center | Gaitnieks T.,Latvian State Forest Research Institute Silava
Research for Rural Development | Year: 2014

In Latvia, Picea abies and Pinus sylvestris as the commercially most valuable species make more than half of all woodlands. It has been found that about 23% of spruce stands are infected by root rot, caused predominantly by fungal pathogen Heterobasidion annosum s.l. To restrict the spread of root rot in coniferous forests of Latvia, the Joint Stock Company 'Latvijas valsts meži' collaborated with Latvian State Forest Research Institute 'Silava' in 2006 and launched a project for testing the Rotstop biological preparation, containing a suspension of Phlebiopsis gigantea spores. This project had a general task to accomplish Rotstop using technology approbation in Latvia and develop control system. Starting with the year 2008, preparation was used for stump treatment during thinning operations. When analysing the field data, a conclusion made in other studies was confirmed - P. gigantea colonizes pinewood more intensively even in case of improper stump treatment. It implies that the quality of stump treatment is decisive when using Rotstop for rot control in spruce stands.

Kaleja S.,Latvian State Forest Research Institute Silava | Lazdins A.,Forest Sector Competence Center | Zimelis A.,Latvian State Forest Research Institute Silava
Research for Rural Development | Year: 2014

The study aims to find productivity of biofuel production in pre-commercial thinning, depending on the structure of assortments and to identify factors that influence the cost of mechanized tending of young stands. Five work methods were compared in the study, starting from standard thinning (production of sawn timber, pulpwood and firewood) with no use of accumulating device and finalizing with the biofuel method - no other assortments except biofuel are produced and the most intense use of accumulating device is considered. Accumulating device is not used for production of standard round-wood assortments. The experiments were implemented in February - March, 2013. The material produced in the study was used by 'Graanul Pellets' company to evaluate possibilities to use timber extracted in pre-commercial thinning of coniferous stands in production of premium class pellets. The average productivity in different stands is statistically different. The study shows that productivity of harvesting is 3.7 ... 5.1 m3 h-1, which can be increased by more intensive use of accumulation. No difference found between work methods in forwarding trials, but productivity grows with increase of share of firewood. Average loading time 26 min, unloading 3.6 min, average load 6.0 m3. Prime-cost calculation shows that harvesting costs depending on the working method is in the range of 22.4 ... 26.5 EUR m-3. Comparison of potential expenses and incomes demonstrates that economically the most efficient is production of traditional assortments (sawn wood, small size sawn wood, pulp wood and firewood) with an active use of accumulating function.

Lacis R.,Forest Sector Competence Center
Engineering for Rural Development | Year: 2016

The study presents data collection and data analysis principles and techniques applied for structural monitoring of timber-concrete experimental vehicular bridge. The framework of data acquisition for structural health evaluation is divided in two principal stages, namely, pre-monitoring stage and monitoring stage. Rational decision making and optimization of monitoring technical resources are demonstrated by establishing relationships between the measured variables in a context of the characteristics of the chosen measuring techniques. Field data are collected for two fundamental performance parameters of the structure, i.e. bending strains/stresses and deflection at a critical section of the bridge caused by heavy-duty vehicles. High degree of correlation is found between the two variables (r = 0.98) upon which any consequent monitoring activities can be based only on one measurement method found most suitable for long term technical conditions. As a result statistics of the other structural parameter can be derived by the established regression function. Furthermore, differences and causes of data dispersion obtained within the pre-monitoring stage are briefly discussed as well as some basic recommendations regarding the improvement of data reliability of both measuring techniques.

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