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Carbon balance in forest mineral soils in Latvia modelled with Yasso07 soil carbon model Полный текст
2017
Bardulis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lupikis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Stola, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Yasso07 soil carbon model was used to estimate soil carbon balance in dry forest site types (6 site types in total) in Latvia and the results were compared with data from Biosoil2012 soil surveys. Litter input, chemical quality and climatic data are required to run the model. Three different scenarios were used for climate data input – steady climate, climate change + 0.025 °C annually and climate change + 0.05 °C annually. Forest mineral soil is a carbon sink for the whole modelled period - the years of 1990 – 2030. Under steady climate, the average carbon removal is 0.6 t CO2 haE-1 yrE-1, under climate change (+ 0.025 °C) scenario 0.4 t CO2 haE-1 yrE-1, but under climate change (+ 0.05 °C) scenario 0.3 t CO2 haE-1 yrE-1. CO2 removal at the beginning of the period (1990) was 0.35 – 0.38 t CO2 haE-1 yrE-1. Carbon stock modelled with Yasso07 is lower than estimated in Biosoil2012 soil surveys. Differences between modelled and Biosoil2012 results vary from 2 t C haE-1 in the poorest and 41 t CO2 haE-1 in the third poorest site type. Carbon stock modelled with Yasso07 increases from the poorest to the most fertile site type while Biosoil2012 shows an increase from the poorest to the third poorest, and a decrease from the third poorest to the most fertile site type. Underestimation and different trends between Yasso07 and measured carbon stock may be explained by inappropriate equations and models used to estimate non-woody biomass. It is necessary to improve accuracy of input data for non-woody biomass by elaborating national equations and models in order to include Yasso07 in the national GHG inventory.
Показать больше [+] Меньше [-]The impact of management on ground vegetation in Riga’s urban forests Полный текст
2017
Kalnins, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Straupe, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Liepa, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
Urban forests provide ecological and social functions and significantly improve esthetical value of these ecosystems. These forests also function as recreational areas for urban residents. The aim of this study was to assess the influence of understory cutting of different intensity on vegetation and coincidence with Myrtillosa forest type in Mežaparks, Riga. In total nine study sites were established: three sites adjacent to roads where regular undergrowth management is practiced, three adjacent sites to edges of the pathways, where undergrowth management is practiced only occasionally and three adjacent sites to roads where there is no management activity at all. Combined 54 sample plots were created (each sized 10 × 10 m, area 100 m2 ), where vegetation survey was done using Braun-Blanquet method. This study showed that with an increase in the intensity of undergrowth management, in general, the species richness and their coverage increases, or more specifically, the number of herbaceous and moss species increases, but the occurrence of shrub species decreases. In all study sites we observed the development of synantrophic species, especifically, the development of fructification which was indicated by the following species: Sambucus nigra L., Sambucus racemosa L., Amelanchier spicata Lam. If management intensity decreases, the proportion of competitor species decreases, but the proportion of CSR strategy type species stabilizes.
Показать больше [+] Меньше [-]Changes in forest floor and tree vegetation in the level II monitoring plot in Valgunde parish, [Jelgava Municipality, Latvia] Полный текст
2017
Petaja, G., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lupikis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The objective of the research was to characterize the qualitative and quantitative changes in ground and tree vegetation within 10 years since the beginning of observations at Level II forest monitoring plot in Valgunde. Tree height, diameter, stem volume, radial increment, crown condition and cone yield were determined, as well as crown projective cover of each plant species was estimated. To study bioindication, the average Ellenberg’s and Düll’s indicator values for the monitoring plot were estimated. Species composition in the Level II monitoring plot in Valgunde is typical for Myrtillosa forest type – there is a distinct moss layer, in which Hylocomium splendens and Pleurozium schreberi predominate, and Vaccinium myrtillus is the most common in the herb layer. Shrub layer mainly consists of spruce seedlings, and the tree layer – of Scots pine. Changes in vegetation over 10 years are insignificant. It can be explained with no forest management activities occurring within the observation plot, such as logging or fertilization, and it may take a longer time to observe significant changes. Tree stand indicators correspond to the average in Latvia in Myrtillosa type forests, but the tree volume is higher in Valgunde monitoring plot.
Показать больше [+] Меньше [-]Evaluation of productivity and impact on soil of tracked ProSilva F2/2 forwarder in forest thinning Полный текст
2017
Rozitis, G., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Zimelis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Tracked forwarders is one of the solutions for the forest soils with poor bearing capacity providing ability to use well-known technology for reasonable cost to improve accessibility of forest resources. Tracked forwarders are not common in forest nowadays and only a few models are produced serially. The ProSilva F2/2 is a new middle-class forwarder, whose frontal tracks are replaced with big tires, ensuring large contact surface, increased mobility of the machine and significantly reduced mass without loosing the load capacity (15 tonnes). The aim of the study was to evaluate productivity, soil impact and cost of the roundwood forwarding using the ProSilva F2/2. The study was conducted in Finland. Productivity (time per crane cycle, split into operations and loads), load size, depth of ruts and soil compaction were estimated during the study. According to the study results, the average productivity is 16 m**3 per hour (driving distance to a landing site 200 m, driving speed 2.8 km hE-1, average load 9.7 m**3). The productivity can be significantly increased by more efficient utilization of the load capacity and by using gripper with the tilt function. The length of ruts on peat soil (56 m haE-1) does not exceed the permitted threshold values in Latvia. The compaction of soil took place mainly in topsoil, no changes in soil density were observed in deeper soil layers. The prime cost of forwarding according to the preliminary estimates is 2.5 € mE-3 if the annual production is at least 62000 m**3. Utilization rate is important to keep forwarding cost low.
Показать больше [+] Меньше [-]The impact of feed rollers on the quality of timber in the manufacturing of posts Полный текст
2017
Zimelis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Abele, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of the study was to determine the impact of the harvester cutting head feed roller type on the mechanical damages of processed roundwood timber in post manufacturing. The study presents the comparison of the gentle Moipu plate wheel rollers and conventional feed rollers having bigger spikes (hereinafter named - conventional feed rollers). The total amount of segments processed with the gentle Moipu plate wheel rollers was 2199, whereas the amount of segments processed using the conventional feed rollers was 5308. When processing roundwood with the gentle feed rollers, in the 1st flow 8.2% of timber was rejected as substandard due to defects. The corresponding figure in the 2nd flow was 5.2% of the material in which the damage in the form studs was caused by the feed rollers. When processing the timber with conventional feed rollers, the percentage of the damage – dents caused by these rollers in the 1st flow was 26.7%, in the 2nd flow – 43.7% and in the 3rd flow only 2.7%. Using the method of characteristics proportion comparison, significant differences have been observed between feed rollers (t = 17.8 is greater than t sub(0.05;∞) = 1.96).
Показать больше [+] Меньше [-]Quality changes during summer – autumn long term storage of birch (Betula pendula) roundwood Полный текст
2017
Magaznieks, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Millers, M., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gžibovska, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
The homogeneous and light wood of birch is suitable for different types of treatment processes and is highly valued for products where visual aspect is important, however, birch assortments are highly susceptible to damages caused by fungi during the storage. Such fungal damages cause discoloration of birch roundwood intended for further woodworking. Sapwood discoloration development and its influencing factors for birch roundwood were analyzed in the summer - autumn period of the year 2016 (August, September and October). Control cut for assessment of sapwood discoloration development was made in four birch roundwood stacks in the districts of Auce and Daugavpils. In order to evaluate the influence of harvesting type, side surface damages, placement in pile, storage duration, diameter, distance from the end plane, daily average temperatures, precipitation amount and relative humidity on development of sapwood discoloration, 616 discs from birch log end planes were prepared. After conducting multiple factor linear regression, it was concluded that a significant development of discoloration and its changes for birch roundwood are promoted by harvesting type, placement in pile, distance from the end plane, daily average temperatures and relative humidity (R2 = 0.450). For birch logs that are prepared by harvester with the daily average air temperature + 6 °C, the first signs of discoloration appear after 17 – 18 days, but on all logs stacked in pile they appear after 68 – 69 days. Whereas, with the daily average temperature of + 18 °C, the first signs of discoloration can occur after only six days, but on all logs stacked in pile they appear after 23 days.
Показать больше [+] Меньше [-]Analysis of damaged land changes in Klaipeda County of Lithuania Полный текст
2017
Ivaviciute, G., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania);Kaunas Forestry and Environmental Engineering Univ. of Applied Sciences (Lithuania);Klaipeda State Univ. of Applied Sciences (Lithuania)
The article presents the analysis of the current situation of the damaged land in Klaipeda County. The study found that the number of affected areas in the county – 266. Because the damaged areas consist of mineral quarries and territories occupied by dumps, the article contains the description and condition of these areas. It was found that mostly sand deposits (60) predominate in Klaipeda County, of which only 8 are used. The smallest number of the deposits – the salt deposits (2). The mainly used deposits in the county are sand and gravel deposits – 29, unused – sand deposits (52). The Klaipeda municipal waste management region comprises 7 municipalities, 39 old landfills and dumps were shut down. At present, 1 regional non-hazardous waste landfill has been arranged. In Klaipeda County, in 2015, damaged land occupied 2,391.06 hectares and amounted to 0.46 percent of the county’s area. During the period between the years 2005 and 2015 the damaged land area in Klaipeda County increased by 130.25 hectares. The analysis of the damaged land by type of ownership showed that the damaged land areas in private land increased by 75.54 hectares or 58.52 percent. In the state land, the damaged land area decreased by 442.35 hectares or 20.04 percent.
Показать больше [+] Меньше [-]The effect of vacuum cooking on enteral food made from fresh and semi-finished ingredients Полный текст
2017
Ozola, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kampuse, S., Latvia Univ. of Agriculture, Jelgava (Latvia)
Enteral feeding also known as enteral nutrition is nutrient delivery into the stomach. Products for enteral nutrition are a specific group of products designed to provide nutrients to the human body in case of various diseases and after surgery, when the daily intake of the product is affected. Today market offers special dietetic products, which are supplemented with synthetic vitamins and minerals, which bioavailability in the body is lower than that of natural organic complexes. Therefore it is important to develop special dietetic products from natural raw materials. The aim of this study was to evaluate the effect of vacuum cooking on the content of bioactive compounds, soluble solids, pH and shelf life of enteral food made from fresh and semi-finished (heated) fruit and vegetable juices. For this research enteral food was made using fresh or semi-finished fruit and vegetable juices. Products were vacuum cooked in 0.02 MPa pressure, with boiling point 67 °C, and 0.06 MPa pressure at 79 °C, withstander for 15 min. All samples were stored at room temperature and tested for their content of vitamin C, total carotenoids, anthocyanins, total phenols and antioxidant activity and microbiological safety, as control untreated enteral food samples were used. The obtained data showed that samples made from semi-finished juices have higher contents of vitamin C and total carotenoids and anthocyanins than samples prepared from fresh juices, but this wasn’t observed with content of total phenols and antiradical scavenging activity (DPPH), where the type of ingredients used for sample preparation had no significant effect.
Показать больше [+] Меньше [-]Recording birth weight has no significance in village based genetic improvement programs of small ruminants Полный текст
2016
Jembere, T. | Kebede, K. | Rischkowsky, Barbara A. | Haile, Aynalem | Okeyo Mwai, Ally | Dessie, Tadelle
Community based sheep breeding programs: Tapping into indigenous knowledge Полный текст
2013
Haile, Aynalem | Mirkena, Tadele | Duguma, Gemeda | Wurzinger, Maria | Rischkowsky, Barbara | Tibbo, Markos | Mwai, Ally Okeyo | Sölkner, Johann
A study was undertaken to understand local knowledge and practices of communities in animal management as a step in designing and implementation of communitybased breeding programs for four local breeds (Afar, Bonga, Horro and Menz) in four sites in Ethiopia. Workshops were held with the project communities to learn their animal management practices, among others the selection of rams and ewes, ram sharing and grazing management. Breeding management skills were studied by conducting heritability and genetic correlation exercises. The most important animal traits for the different production systems were identified from a systems study. Phenotypic, production, and reproduction traits were used either in the form of drawings or verbal explanations. Pairwise combinations of the traits were presented to the communities to express their choices via voting. For evaluating heritability, the communities were asked which trait pair is relatively more heritable than the other. For the correlation exercise, the communities were asked to estimate the magnitude (high, low, and none) of relationship between the traits in each pair. The results indicate that farmers and pastoralists have good skills in sheep management. Although the mating system is generally uncontrolled, the farmers have a tradition of exchanging of rams. All farmers/pastoralists exercise ewe and ram selection based on phenotypic appearance and recalled pedigree. Their knowledge on heritability of traits and genetic correlations between traits more or less concurs with scientific evidence in literature. For example, qualitative traits (like colour) were judged highly heritable followed by production traits. Knowledge of correlations is used for indirect selection when the target traits are either impossible to assess on the live animal or are sexlimited. Indigenous knowledge and existing practices in the communities, developed through years of practical experience, provide an excellent basis for designing sheep breeding programs.
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