Elias Pipinis* (1),  Elias Milios (2),  Miltiadis Georgiou (1), and Pavlos Smiris (1)

1. Laboratory of Silviculture, Department of Forestry and Natural Environment, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. *E-mail: epipinis@for.auth.gr

2. Department of Forestry and Management of the Environment and Natural Resources, Democritus University of Thrace, Pandazidou 193, 68200 Orestiada, Greece.
 

The present study aims at investigating the effects of gibberellic acid (GA3) application and cold stratification on the germination of Sorbus domestica L. and Sorbus torminalis (L.) Crantz seeds. In particular, seeds of both species were treated with 500, 1000 and 2000 ppm GA3 for 30 hours and were, subsequently, cold stratified at 3-5 ºC for 0, 1, 2 and 3 months. In addition, seeds from each species were only cold stratified for 0, 1, 2 and 3 months (control). In both species, non-stratified and 1-month cold stratified seeds, despite having been treated with GA3 solutions, exhibited very low germination percentages (0.8-4.2 % for S. domestica and 0.0-1.7 % for S. torminalis). However, in control seeds and seeds treated with GA3 solutions an increase in the cold stratification period from 2 to 3 months increased germination percentages significantly in both species. In S. domestica, after a 2-month period of cold stratification, the germination percentage of the seeds treated with 2000 ppm GA3 (30.8 %) was significantly higher than that of control seeds (18.3 %). In 3 months of cold stratification, there were no significant differences in the germination percentages between control seeds (87.5 %) and seeds treated with GA3 solutions (89.2-91.7 %). In S. torminalis, the GA3 application significantly improved the germination of 2 and 3-month cold stratified seeds. After a 2-month period of cold stratification, the germination percentage of seeds, which had been treated with 2000 ppm GA3 (30.0 %), was higher than the germination percentages of the seeds which had been treated with 500 and 1000 ppm (15.8 and 14.2 % respectively). After a 3-month period of cold stratification there were no significant differences in the germination percentages between seeds treated with GA3 solutions (88.3-91.7 %). The results demonstrated that the optimum germination percentages of S. domestica and S. torminalis were obtained after a 3-month cold stratification period. In both species, the application of GA3 did not replace or shorten the required cold stratification period. 

Ralitsa Kuzmanova 

Department of Ecology Protection and Remediation of Environment, Faculty of Ecology and Landscape Architecture, University of Forestry, 10 Kliment Ohridski Blvd., 1797 Sofia, Bulgaria. E-mail: ralitsa.t.kuzmanova@gmail.com

In the frame of implementation of International Cooperative Program 'Forests' - second level - (ICP Forests), since 2011 phenologycal observations of beech vegetation in the station of 'Vitinya' were conducted. The targets of this study, along with the data from the many years of observations (2001), related to the assessment of defoliation, phytocenotic changes, leaf analysis, meteorological parameters, air pollution, soil, etc., were to identify the key factors and processes in the functioning of it. The results of observations of the phenologycal development of common beech (Fagus sylvatica L.) in 2012 are: duration of vegetation, start and end of leafing, timing of autumn discolouration of leaves, beginning and end of leaf fall. Assessment of the results was combined with the average minimum and maximum air temperature in 2011 and 2012 and average monthly relative air humidity in both years. 

Vera Lavadinovic (1)*, Vukan Lavadinovic (2), and Zoran Poduska (1) 

1. Institute of Forestry, Kneza Viseslava 3, Belgrade, Serbia. *E-mail: veralava@eunet.rs.

2. Faculty of Forestry, Kneza Viseslava 1, Belgrade, Serbia. E-mail: vukan.lavadinovic@sfb.ac.rs

Rehabilitation of degraded forest ecosystems requires introduction of fast-growing productive and adaptive tree species, such as Douglas-fir. However, introduction of new species always carries an element of risk. This risk can be decreased by appropriate testing. Therefore, it is necessary to investigate the origin and success of species and to select the most suitable provenances. A very important stage in the process of provenance testing is the early control of seed material, which can improve and increase the growth of good-quality seedlings and provide better results in afforestation and establishment of new vegetation. Therefore, the Institute of Forestry in Belgrade set the germination test of Douglas-fir seed under different test conditions in order to identify and select the best seed sources for afforestation. Original Douglas-fir seed of different provenances in Canada was taken as seed material. The test included collection of seeds originating from thirteen different provenances in natural forests of Canada. The aim of the research was to determine the potentials and germination differences among the seeds of common provenances in different conditions - in laboratory and in nursery - and to select the best provenances. The relationship of seed germination and the geographic origin could be another important indicator for selection of Douglas-fir provenances. Regression and correlation analyses were used to determine the statistical dependence of the seed germination in different condition on the geographical origin of Douglas-fir seeds.