Home > Search Results: keywords:"index listovej plochy"
Search:
Search Tips :: Advanced Search
Search collections:
Sort by: Display results: Output format:
National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Index listovej plochy a priestorová distribúcia asimilačného aparátu v poraste buku lesného (Fagus sylvatica L.)
 Haninec, Pavel
One of the most important parameters determining penetration of the photosynthetically active radiation (FAR) through the forest canopy is the leaf area index (LAI). In this thesis we concerned with a comparison of direct and indirect approaches of determining LAI and the vertical distribution of LAI in the canopy. There have been used three optical methods, using the device LiCor LAI 2200 Plant Canopy Analyzer, LaiPen and hemispherical photography. Also, we used the method of estimation LAI using airborne laser scanning. There was created allometric relationship between leaf area and the perimeter of the sample trees. These trees were also destructively processed and based on those, there were created the diagrams of the vertical distribution of leaves in the crowns of these trees. The individual values of the measured leaf area index, were in amplitude from 3.69 m2.m-2 to 11.80 m2.m-2 and the indirect methods underestimated the direct approach in average of 28.46%.
Detailed record
Porovnanie rôznych prístupov k stanoveniu indexu listovej plochy
 Haninec, Pavel
Leaf area index (LAI) is one of the most important characteristics of forest stand affecting fundamentals of tree physiological processes, biomass production or mechanical stability. The aim of this thesis was to compare three different methods (gravimetrical, optical -- LAI 2000 plant canopy analyzer - and needle method) for estimation of LAI. Additionally, the seasonal development of LAI was measured using the LAI 2000 method. Research was conducted in three European beech (Fagus sylvatica L.) and one sycamore maple (Acer pseudoplatanus L.) stands. The age of forest stands was from 13 to 77 years. Seasonal development of LAI followed general pattern typical for broadleaf stands in central Europe, with fastest rate of leaf growth in the first month following budbreak. Maximal LAI was observed in mid-June and July and it was 4.52 -- 5.08 m2m-2 in beech and 4 m2m-2 in maple stand. LAI 2000 underestimated the gravimetrically measured LAI on average by 15.1 % in beech stands and by 5.8 % in maple stand (these differences were not statistically significant). Needle method underestimated gravimetrical LAI in beech on average by 22 % and in a maple stand by 40 % (this difference was significant in three out of four stands). Overall, gravimetrical method is most laborious but provides most accurate results. LAI 2000 slightly underestimates results (albeit not significantly in broadleaf species) but enables multiple measurements of LAI in the course of growing season. Needle method is inexpensive and easy to use but it significantly underestimates LAI. Its use for comparison of multiple species will always require calibration.
Detailed record

Interested in being notified about new results for this query?
Subscribe to the RSS feed.
Digital Repository :: Search :: Submit :: Personalize :: Help
Powered by Invenio v1.1.2
Maintained by admin.invenio@techlib.cz
This site is also available in the following languages:
Česky  English