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The influence of different inventory techniques on the geometrical accuracy of forest geographic data
2008
Bikuviene, I., Lithuanian Univ. of Agriculture, Akademija, Kauno reg. (Lithuania)
This paper deals with the evaluation of the geometrical accuracy of Lithuanian forests compartments geographical data that has been developed using different forest inventory techniques. Geo-reference background database GDB10LT was used as the standard for comparisons. 2500 control points on clearly identifiable places – crossroads, dikes’ intersections, etc. – were selected randomly. The main finding was that the maximal positional root mean square error of clearly identifiable objects in forestry geographic data was 16.47 m (12.37 m and 10.87 m for X and Y coordinates respectively). However, such rather big errors refer to the techniques of GIS database development using paper topographic maps as a background for forest maps and manual digitizing. Enhancement of techniques for GIS database development was found to lead to significant increase in geometrical accuracy of the information.
Mostrar más [+] Menos [-]Estimation of productivity and quality of different origin Scots pine in Latvia
2008
Neimane, U., Latvia Univ. of Agriculture, Jelgava (Latvia)
The productivity and quality of different origin Scots pine (Pinus sylvestris L.) progenies at the age of 43 were estimated. The investigation was carried out in 1964. The seeds from six stands growing on mineral and peaty soils in different environmental conditions were sowed. The thinning was done in 2006. The following growth and quality characters were investigated: height of the trees, diameter at breast height, stem volume, standing volume, branch free tree length, branch thickness, branch angle, stem’s straightness. The growth and quality differences of the progenies depending on the seed origin were estimated. The environmental conditions of the Zvirgzde origin place and the test locality were similar. The progeny of the Zvirgzde stand showed superiority in the growth traits (height, diameter, stem volume) as well as good stem quality and high quality of the assortment outcome in thinning. The progeny of the swamp stand (Tireli) had low values in all investigated traits. A significant influence of the environmental conditions of the seeds origin place on the growth and quality of the progeny was found out. Environmental conditions of seeds origin locality and place of forest regeneration have to be similar to avoid decrease of progeny stand’s growth and quality.
Mostrar más [+] Menos [-]Grey alder (Alnus incana (L.) moench) structure
2008
Miezite, O., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dreimanis, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Grey alder occupies 190.6 thousand ha or 6.8% of forests in Latvia. Stand structure has influence on its productivity and dynamics. Materials for the studies were collected in the period from 2005 to 2007. For the investigation 47, grey alder stands, representing various ages, site index and density conditions from Jelgava, Bauska, Ogre, Aizkraukle, Jēkabpils, Valmiera, Talsi and Krāslava regions were used. The majority of these stands have not been managed previously and have been originated from shoots. A total of 11 – 30 - year - old grey alder stands were investigated using a 6 - tree sample plot method. Trees were grouped in 2 cm diameter classes according to breast height diameter. Trees according to reduction numbers were grouped in natural diameter classes. In 11 – 15 - year - old stands trees were within 4 - 5 two centimetre diameter classes, in 16 - 30 – year - old stands – within 6 - 12 classes. The proportions of trees in smallest and largest diameter classes not exceed 1 - 3%. The distribution of grey alder trees in natural diameter classes in 2/3 of cases match up with theoretical Tjurin distribution, resemblance was not detected in cases, when there are large proportions of thin trees in stand. Cumulative percent values of the number of trees and stand volume are were not dependent on site index. Relationship between cumulated value of the number of trees (y) in percents and cumulated value of stand volume (x) was described by parabolic equation (R2 = 0.997, p is less than 0.05). Fifty percent from stand volume were made up from 70% of thinnest trees. Regression equations describing dependence of tree height, height of live crown base, and length of crown from tree diameter were developed.
Mostrar más [+] Menos [-]Optimization of harvesting sites maximal purchase value calculation. 1. Use of forest inventory data
2008
Morozova, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
In forest harvesting process, a logging company and a forest landowner who have various goals concerning forest stands purchase value are involved. The logging company wants to maximize the profit on lower price, but forest landowner - to extract maximum income. Calculating the forest stands value prior to harvesting it is possible to achieve mutually acceptable price. This article describes question statement and primary research of prior calculated and harvested volume difference for further study of forest stands purchase value algorithm optimization. Harvested volume from feed-back data and prior calculated forest stands volume were compared to obtain the difference and understand the economical importance for optimization of harvesting sites maximal value calculation algorithm. For primary study, forest stands prior harvesting calculation model from the logging company was used. Results from prior harvesting calculations were compared with data after harvesting to achieve information about the precision of calculation model. Obtained results showed significant difference between prior calculated and harvested volumes, which in financial matter cause losses to the logging company. Compared to total harvested volume, negative cutting difference was 7% from volume, which in financial terms with annual harvesting of 1 million m**3 make loss of ~2.3 million euro.
Mostrar más [+] Menos [-]The energy wood resource availability from commercial thinnings in Latvia
2008
Osis, M., Latvia Univ. of Agriculture, Jelgava (Latvia)
The article presents the part of PhD studies of the energy wood harvesting technologies in thinning, and its development possibilities. A possibility for energy wood procurement and use in Latvia as a good amount of not used energy, including estimation of how much wood for energy purposes could be available in Latvia is analyzed. Research has been made in two parts using forest stands cutting area in three different ages to get an average volume of energy wood per ha. First part of the research has been done in a 60 years old forest stand cutting area in the way that total chips volume is measured and then recalculated to the thinning area. The average volume from studied forest stand was 20.32 m**3 haE-1. The second part of the study shows that from 30 till 45 years old forest stands cutting area by the measuring possible removal tress, the energy wood volume could be 23.74 – 33.5 m**3 haE-1. Including the slash from this forest stands cutting area the possible volume of wood for energy purposes could be ~ 33 – 47 m**3 haE-1. The calculations also have been done to study available energy wood resources from whole forest stands thinning area. Totally the available energy wood volume in Latvian conditions is 0.85 million m3 yrE-1.
Mostrar más [+] Menos [-]Phosphorus removal in constructed wetlands of subsurface and surface flow
2008
Gasiunas, V., Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst. | Strusevicius, Z., Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.
Constructed wetland (CW) treatment systems are engineered systems designed to treat wastewater with the usage of the same processes that occur in natural wetlands. The full-scale investigations of free water flow surface filters (FWF), subsurface flow filters, including filters of vertical flow (SVF) and horizontal flow (SHF) were carried out in Lithuania. The investigations’ database collected within the study period of 1995-2007 was used for the estimation of phosphorus removal efficiency of different constructed wetlands. It was established that phosphorus removal efficiency depends on construction of filters and the load according to total phosphorus for the area unit of filter surface. Subsurface flow filters are distinguished by better phosphorus removal. At the same load of all filters, i.e., total phosphorus of 0.3 g mE-2 dE-1, the removal efficiency of subsurface flow horizontal, vertical, and free water flow filters reaches 53.0, 46.5 and 28.0%, respectively. The wastewater contains phosphorus in mineral and organic forms. Due to the aerobic conditions in filters of vertical flow, the amount of organic phosphorus removed by SVF is 3 times greater than in horizontal filters. Organic phosphorus in wastewater before the treatment by vertical filters constituted 27% of total P, and after the treatment 21%. In wastewater treated by horizontal filters this ratio was 21% and 31%, respectively.
Mostrar más [+] Menos [-]Effects of topical and systemic atropine [sulphate] on intraocular pressure and pupil diameter in dog's eye
2008
Kovalcuka, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Birgele, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
The objective of this study was to determine the effects of topical 1% atropine sulphate and systemic atropine sulphate on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in dog’s eyes. Ten adult dogs for each treatment were used in this study. Dogs of different age, breed and sex were examined clinically and ophthalmologicaly. All animals were clinically and ophthalmologically healthy. One drop of topical 1% atropine sulphate was used in ten dogs unilaterally, with the contralateral eye acting as a control. IOP and HPD were measured every 5 minutes. In ten dogs systemic atropine sulphate were used intramuscularly (IM) with IOP and HPD measured every 5 minutes. In both study phases IOP and HPD were measured over a total duration of 60 minutes. After unilateral application of topical atropine, IOP increased significantly in the treated eye. A maximum average IOP of 20.3 mmHg in the treated eye was observed 20 minutes after treatment. Maximal pupil dilatation in the treated eye was observed 35 min after treatment. Measurements made after systemic atropine showed an IOP increase in both eyes, showing maximum average IOP increase 25 minutes post-treatment. Maximum average values of HPD were obtained 25 minutes after treatment. The HPD started to decrease 30 minutes after treatment but it was still significantly higher than before treatment (P is less than 0.05). Because of atropine sulphate’s ability to cause significant increase in IOP, it should not be used for diagnosis and treatment of glaucomatous eyes.
Mostrar más [+] Menos [-]Location of helicobacters in the gastric mucosa of domestic dogs (Canis familiaris)
2008
Berzina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Birgele, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
This study was done to evaluate the prevalence and colonization density of helicobacters in the gastric mucosa of domestic dogs (Canis familiaris). Mucosal samples were taken from several places of cardiac, fundic and pyloric gland region of the stomach to detect helicobacters with urease test, brush cytology, and light histological examination. Fourteen dogs of fifteen sampled animals showed positive urease test and the presence of tightly spiraled helicobacters. Positive urease test was observed in 80.4% of all examined samples. Helicobacters were detected in 82.7% of all examined samples by brush cytology and 80.8% of all examined samples by histological examination. Compared to gastric regions, in all employed detection methods have been showed significantly higher prevalence of helicobacters in cardiac and fundic gland region than in the less effected pyloric gland region of the stomach. Histological examination showed the location and colonization density of the bacteria at the superficial epithelium, gastric pits, and deep glandular epithelium of the gastric mucosa in different regions of the stomach. Colonization density of bacteria was evaluated in 4 groups: as absent, mild, moderate, and severe colonization density of helicobacters. Occurrence of helicobacters in the cardiac and fundic gland region showed mild and moderate colonization density of helicobacters at the superficial epithelium and at the gastric pits of the gastric mucosa. Colonization density of spiral-shaped bacteria between the deep glandular epithelium was more pronounced in the pyloric gland region than in the cardiac and fundic gland regions of the gastric mucosa in the domestic dogs.
Mostrar más [+] Menos [-]The evaluation of sensory properties of Latvian semi-hard cheeses
2008
Novikova, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Strautniece, E., Latvia Univ. of Agriculture, Jelgava (Latvia) | Cirovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Annual judging of dairy products including sensory evaluation of local cheese-maker' cheeses proved that the quality of Latvian classical cheeses is various. In fact, in last three competitions three different manufacturers gained the first place in category of Krievijas and Holandes types' cheeses. It indicates instability of Latvian cheese quality. Two types of semi-hard cheeses (Krievijas and Holandes) were selected for testing the quality of Latvian semi-hard cheeses in the beginning of 2008. Krievijas type cheese was selected from three different manufacturers, but Holandes type cheese - from five different manufacturers. Sensory properties such as flavour, structure and colour were measured using line scale method. Statistical analysis of obtained data showed differences between such assessed properties as colour (yellowness), texture (firmness), holes, flavour (acidity and bitterness) in Krievijas type cheese, and colour (yellowness), texture (firmness), flavour (saltiness) in Holandes type cheese.
Mostrar más [+] Menos [-]Lactic acid bacteria in rye sourdough from crude and peeled rye flour
2008
Kozlinskis, E., Latvia Univ. of Agriculture, Jelgava (Latvia) | Skudra, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Klava, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kunkulberga, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
In Latvia the spontaneous sourdough is used in traditional rye bread baking whose microflora is determined in flour and in microorganism cultures presented in external environment. Almost all spontaneous sourdough cultures, especially those that have been maintained for a long time, contain both lactic acid bacteria (LAB) and yeasts. The main purpose of the current research was to analyze growth dynamics of LAB in spontaneous rye flour sourdough and to isolate some of its representatives. Experiments were carried out in the Department of Food Technology of the Faculty of Food Technology of Latvia University of Agriculture in January and February 2008. Considering differences in constituents, two types of flour were used in the research - peeled and crude rye flour. There were three stages of spontaneous sourdough preparation in 72 hours totally; the renewal of sourdough was realized each 24 hours. The dynamics of LAB plate count in every stage of fermentation was investigated as well as changes of pH was observed using standard methods. The results of experiments show substantial increase in amount of LAB in both sourdoughs, particularly in sourdough from peeled flour, reaching 6.06 log10 cfu mlE-1. A significant decrease of pH value from pH 6.7 to pH 3.8 during fermentation process was observed. As a result, the sourdough from peeled flour had desirable properties for preparation of sourdough starter. LAB cultures isolated and identified from current sourdoughs using API tests: Lactobacillus brevis and Lactobacillus fermentum are also typical members of sourdoughs found in other countries.
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