Zaraženost bijelom imelom i status ishrane obične jele u Gorskom kotaru | Infestation of Common Mistletoe and Nutrition Status of Silver Fir in Gorski Kotar (Croatia)
2011
Diminić, Danko | Potočić, Nenad | Jazbec, Anamarija | Županić, Miljenko
In the region of Gorski Kotar 6 sites (localities) of Silver fir (Abies alba Mill.) were selected to investigate the health status of trees, the infestation by common mistletoe (Viscum album L. ssp. abietis /Wiesb./ Abromeit), and to reveal the nutrition status of fir trees and mistletoes. Three localities were selected on soil sub-types based on silicate and three on limestone-dolomite (Table 1). In the period 2003–2005, from the end of September to the beginning of November, 15 fir trees were randomly selected on each site and evaluated according to crown defoliation with a 5% precision using the criteria and methods of UN/ECE ICP Forests. The diameter of the selected trees was measured at breast height. The trees height and their age on stumps were determined after felling. The crowns were examined in detail; the mistletoes were removed and counted to reveal the number of parasitic plants, and weighed to obtain their crown biomass per each site (Tables 2-7). This paper presents the analyses of 90 trees in total. Samples of fir needles and mistletoe leaves were collected for nutrition analyses from the upper 1/3 of the crown. Needle samples (1- and 2-year old) were dried at 105°C, weighed, and analyzed for the total amount of nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese and zinc. In total, the results are given of the analyses of 180 needles and 17 mistletoe samples. In October 2008 the repeated collection of needle samples was carried out on the same sites in 5 fir trees of a good vitality with crown defoliation <25%. Each site was represented by a composite sample of 1- and 2-year old needles. The same procedure was performed to analyze samples. Soil samples were also taken as composite samples for each site from two soil depths 0-30 and 30-60 cm, using the Holland drill. Standardized soil analyses were performed to obtain the total nitrogen, plant available phosphorus and potassium, and for the determination of pH.
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