Original scientific paper
Intensity of Infection with Yellow Mistletoe and White-berried Mistletoe on the Area of the Forest Administrations Zagreb and Koprivnica
Marilena Idžojtić
; Šumarski fakultet Sveučilišta u Zagrebu
Milan Glavaš
; Šumarski fakultet Sveučilišta u Zagrebu
Marko Zebec
; Šumarski fakultet Sveučilišta u Zagrebu
Renata Pernar
; Šumarski fakultet Sveučilišta u Zagrebu
Željka Kušan
; Hrvatske šume UŠP Zagreb
Đurđica List
; Hrvatske šume UŠP Koprivnica
Mirjana Grahovac-Tremski
; Hrvatske šume UŠP Koprivnica
Abstract
The intensity of infection of different hosts with yellow mistletoe (Loranthus europaeus Jacq.) and white-berried mistletoe (Viscum album L. ssp. album) was carried out in the area administered by Hrvatske šume d.o.o. (Croatian Forests Co.Ltd.), in the area of 10 forest offices of the Forest Administration Zagreb and 5 forest offices of the Forest Administration Koprivnica. The investigated hosts were: sessile oak (Quercus petraea /Matt./ Liebl.), pedunculate oak (Q. robur L.), narrow-leaved ash (Fraxinus angustifolia Vahl), common locust (Robinia pseudoacacia L.), sycamore (Acer pseudoplatanus L.) and black alder (Alnus glutinosa /L./ Gaertn.). In the selected subcompartments older than 30 years, through a diagonal survey the number of infected and non-infected trees, as well as the number of mistletoe plants on infected trees was registered. The intensity of infection was very different in the individual compartments, management units and forest offices. The spatial distribution of the intensity of infection of the sessile and pedunculate oaks with yellow mistletoe in three management units was shown.
In the area of the Forest Administration Zagreb from the total number of examined sessile oak trees 14.2 % were infected with yellow mistletoe. On the average on each of the infected trees there were 2 mistletoe plants, and the largest number on one tree was 18. The largest infection was noted in the Management Unit Zlatarske prigorske šume, of the Forest Office Zlatar (23.9 %). In the area of the Forest Administration Koprivnica 7.8 % of the examined sessile oak trees were infected with yellow mistletoe. On the infected trees there were 3 mistletoe plants on the average, and the largest number of plants on one tree was 11. In the Management Unit Kalnik-Kolačka, of the Forest Office Križevci, there was the largest infestation (9.7 %).
In the area of the Forest Administration Zagreb, yellow mistletoe was observed on 9.2 % of the examined pedunculate oak trees. On the infected trees there were 2 mistletoe plants on the average, and the highest number of plants on one tree was 12. The largest infestation was found in the Management Unit Obreški lug, of the Forest Office Remetinec, where 16.8 % of the examined trees were infected. Yellow mistletoe was present on 11.9 % of the examined pedunculate oak trees in the area of the Forest Administration Koprivnica. On the average 4 mistletoe plants were growing on the infected trees, and the maximum number of plants counted on one tree was 20. The most infected management unit was Križevačke prigorske šume, of the Forest office Križevci, 22.3 %.
For the sessile oak a data base of stand and habitat parameters was made out of the management facts (elevation, site quality, exposure, age and crown closure). The data were analyzed in order to establish whether there is a correlation between the mentioned parameters and the intensity of yellow mistletoe infestation.
Out of the total number of examined narrow-leaved ash trees in the area of Forest Administration Zagreb (Forest Offices Lipovljani and Kutina), 3.5 %, were infected with white-berried mistletoe, with an average of 3 mistletoe plants per infected tree; the largest number of plants per tree was 47.
Keywords
Croatian Forests Co.Ltd.; intensity of infection; narrow-leaved ash; pedunculate oak; sessile oak; white-berried mistletoe; yellow mistletoe
Hrčak ID:
24153
URI
Publication date:
30.4.2008.
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