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Some peculiarities of laboratory measured hyperspectral reflectance characteristics of Scots pine and Norway spruce needles Texte intégral
2012
Masaitis, G., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Mozgeris, G., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
The aim of the study was to investigate the properties of hyperspectral reflectance data of Scots pine (Pinus Sylvestris L.) and Norway spruce (Picea Abies L.). The hyperspectral reflectance data was obtained under laboratory conditions from the last season’s needles of healthy 20 year-old trees from the same site. Hyperspectral data was acquired using Themis Vision Systems LLC VNIR 400H portable scanning hyperspectral imaging camera in 400-1000 nm range. Methods of analysis of variance, discriminant analysis and principal component analysis were applied for the hyperspectral data analysis. Differences between Scots pine and Norway spruce reflection data were examined. The most informative spectral range for Norway spruce – Scots pine spectral separation was determined at 666.5 nm – 668.4 nm, most informative waveband - 667.1 nm. Reflectance variations among individual trees of the same species as well as differences in spectral response between needles from northern – southern crown exposition were tested. A significant variation in spectral response of needles of Norway spruce was detected across the whole measured spectral range (955 wavebands) for each sample tree. However, significant variation of spectral response of needles of Scots pine was detected only in 356 out of 955 wavebands for each sample tree. Depending on the crown exposition to the North or South, the reflectance of Scots pine needles differed significantly in 900 spectral bands. No significant differences were detected in 833 wavebands for Norway spruce.
Afficher plus [+] Moins [-]Distribution and status of common juniper (Juniperus communis L.) in Lithuanian pine stands Texte intégral
2012
Vaitkeviciute, R., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
Distribution and status of common juniper (Juniperus communis L.) in Lithuanian Pine stands are investigated in the study. The research was conducted in pure pine stands on sites with normal humidity and poor fertility in South – South Eastern parts of Lithuania. 40 stands were selected for data collection. Temporary rectangular sample plots with area of 10 square m were selected. According to method of underbrush evaluation, diameter root neck level, height and state index was measured for 3 juniper individuals located near the centre of sample plots. The number of sample plots depended on the area of each stand, but it was not lower than 10 in each stand. Average diameter of junipers was 3.03 cm, average height – 2.03 m. It was determined that average density of juniper individuals is 5055 individuals per hectare, and separately in vacciniosum and vaccinio – myrtilosum forest types - 4844 and 5282 individuals per hectare respectively. Average state index of juniper individuals in 6 grade scale was 2.96, which is near to grade 3 (slightly damaged). Results of the study show that distribution, status and dendrometric characteristics of junipers are different in adjacent regions of pine provenance.
Afficher plus [+] Moins [-]The assessment of vegetation diversity in black alder woodland key habitats in Zemgale [Latvia] Texte intégral
2012
Liepa, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Straupe, I., Latvia Univ. of Agriculture, Jelgava (Latvia
The article focuses on vegetation diversity in the black alder Alnus glutinosa (L.) Gaertn. woodland key habitats in Zemgale, Latvia. Together nine sample plots were established on these habitat types, where next stand South – South West (S-SW) side at the age 1-10; 20-30 and 40-50 years. The vegetation survey has been made in vegetation period of 2010 and 2011. Braun – Blanque method has been used to estimate the projective coverage (%) of tree layer (E3), shrub layer (E2), herb layer (E1) and moss layer (E0) in order to assess the edge effect impact on vegetation diversity according to different ages classes in a next stands of sample plots. The analysis of edge effect verifies that there is a significant influence from the edge in 1st and 3rd zones of sample plots, which lies at S-SW side at the ages 1-10 and 20-30. In sample plots several indicator species of black alder woodland key habitats have been found: Vaccinium myrtillus L., Lycopus europaeus L., Iris pseudacorus L., Comarum palustre L., Plagiomnium ellipticum (Brid.)T.kop. Ordination confirmed that composition of species are relatively close, which demonstrate that species are able to live in similar type growing conditions. Protective species Circaea lutetiana L. and Plagiothecium undulatum (Hedw.) B., S. et G were found on the study sites. Also, adventive species Impatiens parviflora DC was found. Comparing the analysis by zones and sample plots and different age classes, the impact on edge effect has been distinguished in black alder woodland key habitats.
Afficher plus [+] Moins [-]Below-ground biomass production in young stands of Scots pine (Pinus sylvestris L.) on abandoned agricultural land Texte intégral
2012
Bardulis, A., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Jansons, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Liepa, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Tree roots take up a high proportion of forest biomass, and nowadays we use different methods to estimate the root biomass. Methods vary greatly due to the different studies and different excavation methods used. In the summer 2010, a study of the below-ground biomass of young Scots pine Pinus sylvestris L. stands was carried out in central Latvia. In this paper, different below-ground biomass fractions data of 10 sample trees from the abandoned agricultural land plantations were approximated by allometric functions depending on tree stem diameter at breast height 1.3 m (DBH). The main objective was to determine the average below-ground biomass and approximated below-ground biomass fractions by allometric functions depending on tree DBH of young stands of Scots pine on abandoned agricultural land. Our regressions offer good overall approximations of the data. DBH – stump, coarse root and small root and total biomass regressions were highly significant (p is less than 0.001). The most substantial part of total below-ground biomass was from stumps (45%). The smallest shares of the biomass were coarse roots 38% and small roots 16%. The largest portion (52%) of the total fine-root biomass of 12- and 14-year-old Scots pine stands was located at a depth of 0–10 cm, decreasing in deeper mineral soil layers. Total dry (DM) below-ground biomass including fine-root biomass was 19.0 ±5.2 t DM ha-E1.
Afficher plus [+] Moins [-]Evaluation of forest regeneration results after stump extraction in Joint stock company ''Latvian State Forests'' Texte intégral
2012
Zimelis, A., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdans, V., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdina, D., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
With the increase in demand for renewable energy resources, new studies are carried out about under - utilized resources, namely, stumps. To begin to use stumps in industrial application, it is necessary to find out stump extraction influence on the environment, biodiversity, forest regeneration and other important factors. In Zemgale forestry, Misas and Klīves forest districts managed by Joint stock company “Latvian State Forests” (LSF) study on stump extraction in woodlands where clear-cuttings done in 2006 was carried out in the block No. 177, compartments No. 1 and 5, as well as the block No. 176, compartments No. 3 and 9. In these territories two research objects were made where in November-December 2007 stump extraction as well as soil preparation were performed. Main tasks of the project were to evaluate the results of forest natural seeding and coppice ingrowths in natural regeneration areas and evaluate the use of different methods for artificial reforestation with spruce and pine containerized seedlings. It was observed that more seedlings were cut off in the areas where soil scarification with stump extractor was performed if compared to areas prepared with a disc trencher.
Afficher plus [+] Moins [-]Quality control management problems of wooden product surfaces Texte intégral
2012
Stekelis, K., Latvia Univ. of Agriculture, Jelgava (Latvia)
The added value of woodworks is determined by the surface quality because it is the first one seen and evaluated by the client. In the production process it is quite problematic to evaluate woodworks surface quality because of large production capacity, and the processed material can be instrumentally tested with a definite time shift. In production most frequently the surface quality is evaluated visually, which is not quite precise. At the same time during the mechanical processing of wood noise is caused by cutting tools as they gradually wear out. The same reasons influence the increase of noise and the quality of woodwork surface. The essence of the problem is to analyze the registered increase of the noise level at a definite workplace and simultaneously follow the surface quality of the processed material – roughness and wear-out of the cutting instrument. The objective of the paper is to research the method of the noise level data collecting and application in order to evaluate wooden product surface quality during wood processing by milling machines. It would provide an opportunity to update the management processes of massive woodworks, supervise the surface quality of woodworks, reduce costs and increase the added value.
Afficher plus [+] Moins [-]Research of 'duration of load' effects in timber elements in bending Texte intégral
2012
Brokans, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The Duration of Load (DOL) effect is the combined influence of the mechanical loading history and climatic history on the strength of materials. DOL effect is one of the most important characteristics of wood and wood-based materials. The material degradation or damage induces strength reductions. Creep is one of the most important effects of DOL. Creep is a phenomenon that negatively affects functional compliance, behaviour and strength of timber structures in extended years of exploitation. The creep phenomenon is affected by surrounding temperature, relative humidity, timber moisture content and other factors. The study aimed to establish a correct factor system for accurate prediction of long-term deformations of timber structures that is corresponding to environmental conditions and timber properties in the region of Latvia. The experimental research was made in Jelgava, Latvia, and represents timber beam four-point long-term loading in bending with variable cross section height-span length ratio under uncontrolled climatic conditions. There were 12 timber beams with two different span lengths – 1.32 m and 1.50 m used. The timber beam cross section dimensions: height – 60 mm, width – 30 mm. The timber beams were not dried and the moisture content at the start of the experiment varied from 19% to 33%. The applied load values – 0.40 kN and 0.31 kN. Moisture content fluctuations and negative air temperature accelerated creep development and intensity. Prediction of final long-term deformations should rate not only the type of timber material and service class but the strength class, too.
Afficher plus [+] Moins [-]Churchyard elements in Latgale Upland [Latvia] Texte intégral
2012
Markova, M., Latvia Univ. of Agriculture, Jelgava (Latvia)
Churchyard of Latgale Upland is one of the most important parts of cultural historic space of Latvia. The study is based on the materials from expedition made in summer and autumn 2011, as well as on literary studies. Architecturally compositional form of the church is a key part of the landscape, supplemented by other landscape elements. Research and evaluation of the individual elements give specific cultural space characteristics of each investigated area. Visibility in the main view points and links with residential buildings for the churchyard is vital. Each study of landscape area schemes formation is based not only on the church as a domination point expression. Separate churchyard elements - crucifixes, procession paths, burial area, meditation area and a planting in church gardens - are important in describing churchyards. The aim of the research was to find most common elements in churchyards to establish general guidelines for recording and evaluation of the churchyard in Latgale Upland in future. In perspective that could be used as basis for making the landscape typology. Results showed typical landscape elements in the churchyard. In describing churchyards is important to divide typical and unique elements. The research provides information that is important for the further local territorial development plans, focusing attention on the region’s cultural values and identity preservation.
Afficher plus [+] Moins [-]Assessment of landscape ecological aesthetics in urban areas. Example of Jelgava [Latvia] Texte intégral
2012
Jankevica, M., Latvia Univ. of Agriculture, Jelgava (Latvia)
Nowadays, linkage of landscape ecology with landscape aesthetics becomes very topical, especially when people move from rural areas to big towns and cities. Landscape ecological planning becomes more important in terms of sustainable environment. Landscape assessment and investigation needs a multidisciplinary approach. The aim of the study was to evaluate landscape ecological aesthetics in urban area. The selected city for study was Jelgava – city with a special characteristic landscape of Zemgale plains and wide green spaces in the city centre. Jelgava is one of the examples of complex urban system with ecological environment. This research presents landscape evaluation of Jelgava using ecological aesthetics assessment method. Territory of Jelgava was divided in groups of research areas: green spaces, residential areas and other territories. Qualitative and quantitative methods were used in the research. The methods applied in this research describe the present situation of the city. Landscape inventory, biotope structure analysis and evaluation of landscape ecological aesthetical qualities give a general overview of the problems and opportunities of the examined city. Research study was managed in autumn and winter 2011. The results show the need for sorting the cityscape and use of ecological principles in further urban planning. Green areas of Jelgava are ecological and aesthetical valuable but multi-storey residential areas have low quality of landscape ecological aesthetics.
Afficher plus [+] Moins [-]Miklouho-Maclay park - the object of historical, cultural and architectural heritage Texte intégral
2012
Markov, F., Zhytomyr National Agricultural Univ. (Ukraine)
The article is devoted to the analysis of historical, cultural, and architectural importance of Miklouho-Maclay park, a monument of landscape art. It examines the archive data about the family of the famous traveler, ethnographer, anthropologist Mykola Mykolayovych Miklouho-Maclay who lived in Malyn (Zhitomir district Ukraine) at the end of XIX and the beginning of XX century, his contribution to the development of landscape art. It is shown that the park contains 57 species of arboreal-shrub plants including 34 species of trees, 22 shrubs, and one shrubbу liana. 23 of them (40%) are introduced species. The author offers the direction of parkland reconstruction and points out recommendations on territory zoning.
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