Rueckgang der Tannenverjuengung durch die Tannentrieblaus. Bekaempfung durch waldbaulich Massnahmen

1993

11 Lit. Ang.

Unselbständiges Werk

4223

200026701

Besides game, the silver fir woolly aphid, Dreyfusia nordmannianae, is again causing considerable damage to fir regeneration in certain Austrian localities. A more detailed case study revealed that the mode of forest management, i.e. sudden and extreme exposition of fir regeneration to sun and aphid advection by clearcutting and early thinning, is very favourable to the dissemination and establishment of infections. Degree of impact was significantly correlated to light exposition and to neighbourhood of other severly infested trees. A couple of other tested factors obviously had no effect on aphid infection. Modification of silviculture and harvesting methods is proposed, which is expected to provide a long term prevention of detrimental aphid attack, thus sustaining silver fir as an important contribution to forest stability.