Journal of Forest Science, 2004 (vol. 50), issue 9
The effect of stress factors on birch Betula pendula Roth
D. Kaňová, E. Kula
J. For. Sci., 2004, 50(9):399-404 | DOI: 10.17221/4636-JFS 
In a controlled pot trial, plants of birch (Betula pendula Roth) were treated in six variants: acid watering (pH 3), acid watering with spraying, drought, ammonium sulphate fertilisation, ammonium sulphate fertilisation in combination with drought, and control. The response to the treatment with ammonium sulphate in terms of the increment was discordant as it increased the sensitivity of birch to frost. Drought had a negative effect on increments. A combination of ammonium sulphate and drought; drought; ammonium sulphate and sprayed acid watering delayed the shedding of leaves; this was due to a longer vegetation period, significantly higher...
Contribution of regeneration on dead wood to the spontaneous regeneration of a mountain forest
K. Ježek
J. For. Sci., 2004, 50(9):405-414 | DOI: 10.17221/4637-JFS
In the Moravian-Silesian Beskids in the beech/spruce forest vegetation zone, the amount of dead wood was determined (pieces of wood and stumps) in five sample plots in a managed forest and in three plots in the National Nature Reserve (NNR) Kněhyně-Čertův Mlýn. In plots situated in the managed forest, 22 to 50 m3/haof lying wood was found. In the reserve, the volume of fallen wood ranged from 29 to 144 m3/ha. The number of stumps in sample plots in the managed forest ranged from 530 to 980 per ha. In the reserve, the number of new stumps did not increase any more and only stumps from the period before the NNR declaration occurred....
Occurrence, development and natural enemies of cecidogenous generations of Pemphigus gairi Stroyan (Sternorrhyncha, Pemphigidae)
J. Urban
J. For. Sci., 2004, 50(9):415-438 | DOI: 10.17221/4638-JFS
The paper deals with the occurrence, development and natural enemies of the cecidogenous aphid Pemphigus gairi Stroyan (Pemphigidae). The aphid abundantly occurred on leaves of Populus nigra and P. nigra var. italica in Brno in 2003. It was described from England and no information on its occurrence is available in literature from continental Europe. It refers to a holocyclic and heteroecious species. In localities under study, larvae of fundatrices hatched mainly in the last decade of April. Through their sucking on the abaxial face of freshly unfolded leaves of poplars, species-unspecific lengthwise tile-like...
Calculus of variations and its application to division of forest land
M. Matějík
J. For. Sci., 2004, 50(9):439-446 | DOI: 10.17221/4639-JFS
The paper deals with an application of the least squares method (LSM) for the purposes of division and evaluation of land. This method can be used in all cases with redundant number of measurements, in this case of segments of plots. From the mathematical aspect, the minimisation condition of the LSM is a standardised condition ∑ pvv = min., minimising the Euclidean norm ||v||E of an n-dimensional vector of residues of plot segments at simultaneous satisfaction of the given conditions. The traditional procedure of calculus of variations with the use of Lagrangian function is shown. If some additional conditions...