An interspecific factorial hybridization was made, where seven P. strobus female parent trees were mated to four P. wallichiana male trees, in order to transfer genes for resistance to blister-rust from the blue pine to the F1 hybrids. The hybrid seedlings and the open pollinated families of the two parents were three times consecutively inoculated with blister-rust. The six years old seedlings were transplanted in the fi eld in the so called Valiug Experiment 1. The experimental design consisted in 28 hybrid full-sib families and two open pollinated families of the parent species. Plantation took place in a complete randomized block design with three blocks, with 6 to 12 seedlings per linear plot and 3 x 3 m spacing. This paper is based on the measurements made at age 32, just after the fi rst thinning. Diameter at breast height, tree height, tree volume, stem straightness and tree survival were the fi ve measured traits. According to ANOVA, signifi cant (p < 0.05) and highly signifi cant (p < 0.001) differences for diameter at breast height, tree height, volume growth rate, stem straightness and tree survival were detected between hybrid families. Highly signifi cant (p< 0.01, p < 0.001) differences were found between eastern white pine female parents for survival, stem straightness and all growth traits, suggesting that nuclear additive genes are controlling the respective characters. Consequently, high survival or genetic resistance to blister-rust can be found within the P. strobus species even though it is highly susceptible to this pathogen. The P. wallichiana parents exhibited signifi cant additive effects on straightness and breast height diameter, but no signifi cance in height, volume, and tree survival. The contribution of the additive variance to the phenotypic one was 65.7% for diameter, 58.6% for height, 50.5% for volume, 70.4% for stem straightness and 73.4% for tree survival. Hence, additive variance should be employed in a breeding program. The narrow-sense family heritability estimates were 0.657 for diameter, 0.586 for height, 0.505 for volume, 0.705 for stem straightness and 0.734 for tree survival. The individual-tree narrow-sense heritability estimates were 0.336 for diameter, 0.253 for height, 0.205 for volume and 0.121 for stem straightness. Assuming selection of 5, 10, or 15 families out of the 28 tested ones and sexual propagation, a genetic gain of 9.5%, 6.8% and 4.8% in diameter, and 11.2%, 8.1% and 5.7% in volume and 16.4%, 11.8% and 8.4% in tree survival, respectively, might be achieved. Selecting the most outstanding 5%, 10%, or 15% individual F1 hybrids would yield a genetic progress of 9.7%, 8.3% and 7,4% in diameter and 10.2%, 8.8% and 7.8% in volume growth rate. The hybrid population mean surpassed in tree survival the open pollinated eastern white pine mean by 70.7% while the eastern white pine, surpassed the hybrid in all growth traits. The F1 hybrid and P. strobus open pollinated parent species averaged 0.993 and 1.069 m3 volume per tree, respectively. By extrapolation the yield results from the hybrid trial area to 1 ha results in a yield of 559.9 m3 per hectare for hybrids and 602.5 m3 for P. strobus female parent species. In conclusion, hybrids should be taken into consideration and used in plantation programs in high-blister-rust-hazard areas.

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The influence of seed provenances and seedling production methods on quality of one and two years old seedlings of Austrian pine were investigated. Seeds from three provenances of Austrian pine (Goc, Studenica and Sargan) were used for seedlings production, combined with three production methods: (i) the modified seedbeds (bare-root), (ii) the container type Plantagrah II and (iii) the container type Gocko. Provenance, as well as the combined influence of provenance and production method had minimal influence on the variability of one and two years old Austrian pine seedlings. Nevertheless, the production method had the highest influence. The production system, besides its importance in nursery, will have a high influence on seedlings growth during the first year after planting. Considering the results of this study (e.g. the highest values of the diameter, number of lateral roots, shoot and root dry weight, and quality index and the lowest value of SQ and satisfactory value of S:R), we can conclude that the seedlings produced in container type Gocko led to the highest seedlings quality, recommended especially for afforestation on hard sites.
    

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The beech bark necrosis (BBN) infestation severity of European beech (Fagus sylvatica L.) was assessed in regions of Central (CE) and South-Eastern Europe (SE). Altogether more than 10,000 trees were sampled at 114 sites. Using variation partitioning method, we examined the pure and shared effects of stand, site, climate and spatial sets of variables on mean BBN severity. Our rating included (i) the whole stand, (ii) tree social status classes, (iii) canopy (C) and (iv) understory (U) trees separately. We found that C trees were less affected by BBN than sub-canopy and U trees in both regions. There were found inter-regional differences in amount of explained variability (25.473.9%) for whole stand BBN and in the sensitivity of C and U trees to the environmental gradients. The analysis revealed that the climate and spatial variables followed by stand variables had the largest marginal effects on mean BBN severity in all models, while the site set of variables had the weakest one. More than half of the explained variation was shared among four sets of variables in SE, contrary to CE. Except to U trees in SE, the effect of climate pure or spatially structured remained the highest also after partitioning of variance; more in SE than in CE. Taking into account positive association between mean annual temperature and mean BBN severity in C trees in SE, reinforced negative effect of climate change on the necrosis might be expected to be more serious mainly in low situated beech forests there. Promoting the tree species diversity in forested areas with higher incidence of beech bark necrosis, i.e. in low altitudes in SE, could reduce the susceptibility of forests to the necrosis at regional level in the future. For better understanding of the relative importance of environmental and spatial variables on BBN severity, further research performed on finer spatial scale (extent and grain) is necessary, along with accounting for pathogens involved in the infestation.

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The objective of this study is to reveal whether it is possible to predict rainfall, throughfall and stemflow in forest ecosystems with less effort, using several measurements of rainfall interception (hereafter interception) and an artificial neural network based linear regression model (ANN model). To this end, the Kerpe Research Forest in the province of Kocaeli, which houses stands of mixed deciduous-broadleaf forest (Castanea sativa Mill., Fagus orientalis Lipsky, Quercus spp.), black pine (Pinus nigra Arnold), maritime pine (Pinus pinaster Aiton) and Monterey pine (Pinus radiata D. Don), was selected study site. Four different forest stands were observed for a period of two years, during which rainfall, throughfall and stemflow measurements were conducted. These measurements were separately calculated for each individual stand, based on interception values and the use of stemflow data in strict accordance with the rainfall data, and the measured throughfall interception values were compared with values estimated by the ANN model. In this comparison, 70% of the total data was used for testing, and 30% was used for estimation and performance evaluation. No significant differences were found between values predicted with the help of the model and the measured values. In other words, interception values predicted by the ANN models were parallel with the measured values. In this study, the most success was achieved with the models of the Monterey pine stand (r2 = 0.9968; Mean Squared Error MSE = 0.16) and the mixed deciduous forest stand (r² = 0.9964; MSE = 0.08), followed by models of the maritime pine stand (r² = 0.9405; MSE = 1.27) and the black pine stand (r² = 0.843, MSE = 17.36).

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