DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 9-10/1973 str. 67 <-- 67 --> PDF |
4. Lyford, W. H., and Brayton, W. F. (1964): Development of the Root System of Acer Rubrum L., Harvard Forest Paper No 10. 5. Lyr, H. and Hoffmann , G. (1967): Growth Rates and Growth Periodicity of Tree Roots, Inter. Review of Forestry, Vol. 2. 6. Martinović , J. (1965): O iskorištavanju ilimeriziranih tala za uzgoj četinjača na bujadarskom području, Šum. list br. 7/3. 7. Schwerdtfeger , F. (1970): Die Waldkreinkheiten Paul Parey. 8. Stout , B. (1956): Studies of the Root Systems of Deciduous Trees, Horvard Black Rock Forest, Bulletin No. 15. 9. Š k o r i ć, A. (1963): Pedološka karakterizacija i mjere popravka tla pašnjačkih površna u Jastrebarskom, Dokumentacija Jug. instituta za četinjače Jastrebarsko. Summary Die-back of Eastern White Pine (PINUS STROBUS L) in cultures The Eastern White Pine along with Spruce, Scots Pine and European Black P.ne is the most represented species in Croatia´s coniferous cultures. Several years ago was noticed its group- and stemwise dying away. It is more intensive in pure stands than in mixed ones. For the purpose of studying this problem three characteristic localities, viz. Gornje Iz mje, Velika Buna and Dugave, were selected. In all three localities the intensity of die-back was equal and symptoms the same. The needles become light yellow, thereafter reddish-brown and do not fall off. This phenomenon appears most often in circles and usually begins at the lower more humid part of the slope or microdepression. In each of the selected localities was laid out one sample plot for the following- up of the intensity of die-back and performing other investigations. The author´s initial investigations were directed towards the definition of soil conditions on experimental plots, to the search for differences in the development of aboveground and underground parts between the healthy and dead standing trees, to the recording of appearance and intensity of the attack of diseases and of noxious entomofauna. The results achieved are presented in this paper. On the basic of the soil investigations in the localities of Gornje Izimje and Velika Buna a trench-ploughed slope pseudogley was determined, while in the locality of Dugava a wery weakly superficially gleyed lessive soil. The intensity of die-back is influenced by the micro- and mesorelief of terrain which perform a redistribution of precipitation and lateral waters. The performed analyses of sample trees demonstrated that there were no significant differences between the healthy and dead standing specimens in the aboveground part, and no significant differences in the rooting depth either. On the basic of the average lenght of the lateral roots the author established that the area of engaged soil in healthy specimens in relation to that of the dead standing ones is by 20°/o larger. The ratio of the area of angaged soil to crown projection in healthy specimens is 2,59:1, and in the dead standing ones 1,75:1. The fungal diseases honey fungus (Armillaria mellea Vahl.), needle-cast fungi (Hypcdermia desmasierii Duby), Verticicladiella spp. and the noxious entomofauna White P.ne bark aphid (Pineus strobi Htg.), Pine weevils (Hylobius abietis L., Pissodes pini L.), bark beetles (Pityogenes bidentatus Herbst., P. bistridentatus Eich., P. calcographus L., P. quadridens Hart.), Pine cone moth (Dioryctria splendidella H. S.), fox-coloured Pine sawfly (Neodiprion sertifer Geoffr.), which were recorded in selected localities, may be of primary or secondary significante, and in unfavourable site conditions they may be the cause of Eastern White Pine die-back. There exist also the first indications according to which the causative organism might be the determined fungal disease produced by Verticicladiella opp. These investigations are being continued. |