Ancic M.,Svetosimunska cesta 25 |
Pernar R.,Svetosimunska cesta 25 |
Bajic M.,Kaciceva 26 |
Seletkovic A.,Svetosimunska cesta 25 |
Kolic J.,Svetosimunska cesta 25
IForest | Year: 2014
Silver fir is one of the most important commercial and ecological species in Croatia, and is currently the most damaged tree species in Croatian forests. It is increasingly infested by white mistletoe, whose relevant consumption of water and nutrients contributes to physiological weakening of the tree. Early mapping of mistletoe infestation based on remote-sensed methods may overtake current limitations of standard field methods and their high costs in the assessment of tree health over large areas. The main goal of this study was to develop an efficient and reliable method for mistletoe detection based on hyperspectral images and supervised classification methods. Surveying was performed in a mountain area of Croatia characterized by beech-fir forests using a hyperspectral scanner. The Spectral Angle Mapper (SAM) classification with 5° threshold value proved to be the best classification method. The first "spectral signatures" - endmembers for fir and mistletoe, were determined and entered into a spectral library database. Using the above approach, a reliable picture of the spatial distribution of mistletoe-infected silver fir trees over the whole studied area was obtained. Results were validated by aerial surveying with a non-pilot aircraft from ~30 m above the crowns. The approach used here may allow a cost-effective mapping of the distribution and intensity of mistletoe infection in silver fir, and can be considered an helpful tool for forest management and planning, forest protection and harvesting. © SISEF.
Siric I.,University of Zagreb |
Kos I.,University of Zagreb |
Kasap A.,University of Zagreb |
Petkovic F.Z.,Svetosimunska cesta 25 |
Drzaic V.,University of Zagreb
Journal of Central European Agriculture | Year: 2016
The aim of this study was to determine the concentration of heavy metals Fe, Zn, Cu, Ni, Pb i Cd in certain edible species of saprophytic fungi and the substrate on three area of sampling, and to assess the role of individual species as biological indicators of environmental pollution. In this study were used three species of wild edible mushrooms (Agaricus macroarpus Bohus, Clitocybe inversa (Scop. ex Fr.) Pat. and Macrolepiota procera (Scop. ex Fr.) Sing.,). Completely developed and mature fruiting bodies were collected at random selection in localities of Trakošćan, Jaska and Petrova gora. At the same time, the substrate soil samples were collected from the upper horizon (0-10). Determination of heavy metals in mushrooms and the substrate soil were carried out by X-ray Fluorescence Spectrometry. The data obtained were analysed by means of the statistical program SAS V9.2. Significant differences were found in the concentrations of Fe, Zn, Cu, Ni, Pb and Cd between analysed species of mushrooms and localities of sampling (P < 0.05). The highest mean concentrations (mg*kg-1) of Zn (98.25), Cu (88.07), Ni (3.80), Pb (5.06) i Cd (4.12) in Agaricus macrocarpus were determined, while the highest contents of Fe determined in Macrolepiota procera (126.19 mg*kg-1). The average distribution rates of investigated heavy metals in anatomical parts of the fruiting body were significantly different. All mushrooms species were biological exclusors of Fe, Ni and Pb (BCF<1). On the other hand, bio-accumulation features were established in the investigated mushroom species for metals Cd (BCF>1). The consumption of investigated mushrooms poses no toxicological risk to human health due to low concentrations analysed metals. © 2016, University of Zagreb - Faculty of Agriculture. All rights reserved.