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Betrachtungen über Zuwachsverlust an Jungkiefern durch den Ernährungsfraß des Großen Waldgärtners Myelophilus piniperda L. ( Col., Scolytidae )
Author(s) -
Turček F. J.
Publication year - 1964
Publication title -
zeitschrift für angewandte entomologie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0044-2240
DOI - 10.1111/j.1439-0418.1964.tb02946.x
Subject(s) - bark (sound) , shoot , bark beetle , biology , forestry , pinus <genus> , horticulture , botany , geography
Zusammenfassung Durch den Ernährungsfraß des Großen Waldgärtners, Myelophilus piniperda L. ( Ipidae, Coleoptera ), können durch Zerstörung der Triebe schwere Zuwachsverluste an Jungkiefern ( Pinus silvestris ) hervorgerufen werden. In der Arbeit wird versucht, durch eingehende Befallsanalysen auf zwei jüngeren Kulturflächen und anschließende rechnerische Überlegungen zu exakteren Feststellungen über das Ausmaß der Zuwachsverluste zu gelangen. Im vorliegenden Fall, bei 7–9jährigen Kiefernkulturen, ergibt sich allein durch den Ernährungsfraß des Großen Waldgärtners ein jährlicher Zuwachsverlust von 0,056 bis 0,075 m 3 je ha. Summary In two distant afforestations of Scotch pine eight years of age the damage caused by Myelophilus piniperda L. bark beetle by boring the youngest shoots has been studied during the 1963 year. The afforestations studied were at an elevation of about 450 m and 800 m a. s. l., respectively. The mean height of trees made 2 m and the mean density was 5258 saplings per hectare. The distribution of damaged trees showed a strongly clumped pattern and a significant departure from a random, Poissonian distribution. Thereof selection of feed‐trees by the bark beetle is assumed. A mean of 70,5 per cent of all trees present had at least one shot damaged. The mean number of injured shoots per tree made 3,2, while per damaged tree the number was 4,5 shoots. The bark beetle strongly preferred shoots in the upper parts (above 1 m height) of the crowns of pines. Only 2,6 per cent of all shoots damaged were terminal ones. On the basis of the quantitative study carried out, it has been calculated that there were 16681 shoots in average, damaged per hectare. The mean length of the shoots was 11 cm, thus the damaged shoots made 1835 m a year. Per one cm shoots‐length there were 15,8 needles, thus a total of 2 899 158 needles of a weight (fresh) of 77 kg has been destroyed, with fiducial limits 67 and 90 kg, respectively. On the basis of the photosynthetic capacity of the one‐year needles it can be concluded that the mass of needles destroyed is equivalent to about 70 cubic dm wood‐increment, or about 1,6 per cent of the annual increment of one hectare. The estimated true loss varies within a range of 0,056 and 0,075 cubic meters per hectare of the afforestations studied. The frequency distribution of trees with none to (max.) 23 damaged shoots is given on Fig. 1: a‐ distribution found, b — distribution expected (random).