Journal of Forest Science, 2002 (vol. 48), issue 6
Effect of increased nitrogen depositions and drought stress on the development of Scots pine (Pinus sylvestris L.) - II. Root system responseOriginal Paper
E. Palátová
J. For. Sci., 2002, 48(6):237-247 | DOI: 10.17221/11881-JFS 
Effects of drought stress, stress by increased nitrogen depositions and combined effect of the two stress factors on the growth of Scots pine (Pinus sylvestris L.) were studied in two experimental series in 1994-1997. The drought stress was induced by reduction of atmospheric precipitation by 60%, the increased nitrogen depositions were simulated by repeated applications of ammonium sulphate at a dose corresponding to 100 kg N/ha per year. All stress factors under study impacted the biomass, vertical distribution, functionality and mycorrhizal infection of fine roots. The root system responded to simulated stresses as early as from the very...
Occurrence, development and natural enemies of Pemphigus spyrothecae (Homoptera, Pemphigidae)Original Paper
J. Urban
J. For. Sci., 2002, 48(6):248-270 | DOI: 10.17221/11883-JFS
In 2001, galls were analysed of Pemphigus spyrothecae Pass. taken in one- to three-week intervals from Populus nigra and P. nigra var. italica at 4 localities in Brno. Fundatrices matured in the first half of June and during the first half of summer produced about 50 offsprings. Virgines produced about 10 offsprings which grew up in winged sexuparae. The winged individuals started to occur in galls from the beginning of August. In galls with intact development, on average 500 aphids developed. Galls with intact development on P. nigra var. italica reached larger average dimensions...
Pollination success and full seed percentage in European larch (Larix decidua MILL.)Original Paper
B. Slobodník
J. For. Sci., 2002, 48(6):271-280 | DOI: 10.17221/11884-JFS
A relationship between the success of pollination and the percentage of full seeds of European larch (Larix decidua MILL.) was studied using several models of non-linear correlation analysis. Although the proportion of pollinated ovules was high in most cases (especially in the middle parts of open-pollinated conelets), the mean percentage of full seeds was extraordinarily low (after the controlled self-pollination even close to zero) and most of the calculated correlation coefficients are lower than the corresponding critical value. This fact gives an evidence for the strong effect of additional important factors causing the empty seed formation...