1721 research outputs found
Sort by
Solčavski gorski les eštudija o značilnostih in prednostih solčavskega gorskega lesa ter njegovi uporabnosti
Get PDFStable carbon isotopes in Norwey spruce (Picea abies (L.) Karst.) tree rings at two sites in Slovenia
No full textStable isotopes in tree rings are an important tool in climate reconstruction and in studies of tree response on environmental factors in the past, similar like maximum latewood density, tree ring width and other tree ring parameters.In this article we present stable carbon isotopes physiology and the first two Slovenian d13C chronologies for Norway spruce (Picea abies (L.) Karst.) growing at two sites with different ecological conditions. Five trees were sampled at Pokljuka alpine site and three at Sorško polje lowland plantation. d13C values were compared with CRU TS 1.2 meteorological data-set,which provides information on climate in Europe for the 1901-2000 period at a 10ć spatial resolution. Results of correlation analysis for both sites revealed similar average d13C values, which are in strong negative correlation with amount of precipitation and positive correlation with temperatures in the growing period. Temporal stability of the correlation between precipitation and d13C values in July is significant for both sites, where as the stability of d13C - temperature relationship is significant only for the Sorško polje site
Determination of forest fire causes and harmonization of methods for repoting them : deliverable 1.1. State of the art (draft)
Get PDF
The influence of climate on tree-ring maximum latewood density in Norway spruce (Picea abies (L.) Karst.) at two sites in Slovenia
No full textNorway spruce (Picea abies (L.) Karst.) is frequently the object of dendrochronological research owing to its distribution, wood structure and longevity. The Norway spruce chronologies published in Slovenia so far have been based on tree-ring widths. This article presents the first density chronologies and describes the method of determining maximum latewood density (MXD). Two different sampling sites were selected (Pokljuka and Sorško polje) and 13 sampling cores were taken from each site. The results showed positive correlation between MXD and temperatures in August and September. Furthermore,higher MXD values and less pointer years were observed at the lowland Sorško polje site
Information gap analysis of the Slovenian forest inventory data in the light of MCPFE requirements
No full textWithin the framework of the European MCPFE process, the state of forests and forest management is assessed on the basis of the state and changes of six Helsinki criteria and subordinated sustainable management indicators. We have identified gaps - information gaps - between information requirements of quantitative MCPFE indicators and available forest inventory data. Gaps were identified according to seven quality criteria. The biggest information gaps were identified in the 3rd - state of indicators - and in the 4th Helsinki criteria - changes of indicators. The main reasons for this lie in the fact that forest inventory does not offer any data for two indicators of the 3rd and one indicator of the 4th Helsinki criteria, and the fact that in many cases data exist only for a single period. Definitions that are not harmonized, spatial incompleteness of data and lack of clarity in methodologies also contribute to these gaps. To reduce information gaps, new forest characteristic indicators should be introduced in data obtaining protocols (e.g. forest types, even-/uneven-aged stands, types of regeneration), processes should be based on clear statistical principles, which have to be documented
Polyphenols in different larch (Larix spp.) species
No full textVarious types of polyphenolic compounds, such as lignans, oligolignans and flavonoids, which occur in different tissues of wood from the larch (Larix) genus, are presented in the article. Their biosynthesis, chemical structure and properties, including a distinctive antioxidative potential, are described. The methods of quantitative isolation from wood as well as their chemical characterization by means of sophisticated chromatographic analytical techniques are presented. It has been experimentally established that the highest concentrations of lignans and flavonoids are present in knots, branches and bark of trees. The most important flavonoid in larch tissues is taksifolin, while the predominating lignans in knots are secoisolariciresinol and less abundant lariciresinol and cycloisolariciresinol. The presence of polyphenols is crucial for wood durability, as these compounds represent efficient chemical protection of wood against biological decay. Due to high concentrations of bioactive lignans in knots of conifers, the latter represent a suitable source for technological production of valuable substances
Microscopy techniques to study wood formation in beech
No full textWe studied wood formation in beech (Fagus sylvatica), using intact tissue samples containing xylem, cambial zone and phloem. The samples were taken from adult trees growing at the forest site Panška reka near Ljubljana at weekly intervals during the 2006 vegetation period. Light microscopy (LM), UVmicrospectrophotometry (UMSP) and transmission electron microscopy (TEM) were used for analyses. LM (bright field and polarization mode) and image
analysis were used for investigation of cell divisions in the cambial zone and xylem formation. We determined lignin content in forming cell walls with UMSP. TEM was used to follow the deposition of cell wall layers. The methods used enabled us to investigate wood formation at different levels. Cell divisions started at the end of April and ended from the end of July till mid August. The main part of the growth ring in the wood was formed from May till July. The first formed vessels were completely formed in approximately one month and the first formed fibres in approximately two months
Natural regeneration ecology of a secondary altimontane spruce forests at Jelendol
No full textNatural regeneration of altimontane spruce forests at Jelendol is retarded dueto many factors. In autumn 2003, gaps of different size and parts of the surrounding stand were covered with a 5 x 5 grid m to define sampling plots. Atotal of 227 plots with 1,5 x 1,5 m in size were installed to analyse generalregeneration conditions and inhibitors. The following ecological parameters were estimated on each plot: micro relief, inclination, soil depth,ground cover, direct and diffuse solar radiation. Woody regeneration (density, height, height increment) and ground vegetation were recorded at each plot. Considering that N-S and E-W radiation asymmetry was explicit, the distribution of direct and diffuse radiation was divided into four groups among the plots. Spruce regeneration (28.,605 per ha) was mainly found at the edge of the large gap, though total regeneration density and radiation were not correlated. However, in both the stand and the small gaps, the lack of radiation hindered further development. This study showed that light conditions were not the only factors affecting the regeneration success at an altitude of 1,500 m. The presence of woody debris was important, while the influence of the herb layer (predominant species were Festuca altissima All. and Calamagrostis arundinacea (L.) Roth.) and soil depth proved to be negative. The impact of browsing, however, remained the main problem
