Elias Pipinis

DIAMETER AT BREAST HEIGHT ESTIMATED FROM STUMPS IN Quercus frainetto IN THE REGION OF EVROS IN NORTHEASTERN GREECE

For foresters, it is sometimes required to estimate the diameter at breast height of tree that has been cut, though it is often only the stump that is available as an indicator of size, after illegal logging and quick removal of the cut trees from the forest. In this study, equations for predicting the diameter at breast height, were fit specifically for Quercus frainetto in the region of Evros in northeastern Greece. The selected equations (quadratic model) were, where is the estimated diameter at breast height d (cm), and dst is the measured diameter at stump height (cm); for pure stands (R2 = 0.94); for mixed stands (R2 = 0.92); for the whole forest (R2 = 0.94).

Treatments for seed germination improvement in Prunus azorica, Frangula azorica and Morella faya, three native species of Azores Islands

Abstract The aim of this study was to determine the best treatment to maximize seed germination of three native species of the Azores islands (Prunus azorica, Frangula azorica and Morella faya). In all three species the effect of gibberellic acid (GA3) application and cold stratification on seed germination under controlled conditions (light and temperature) was investigated. In particular, seeds of all three species were treated with 500 and 1000 mg L–1 GA3 for 24 hours and were subsequently cold stratified at 3–5°C for 0, 1 and 2 months. In addition, seeds from each species were only cold stratified for 0, 1 and 2 months and also seeds with the endocarp (stones) of P. azorica only were subjected to outdoor stratification from 1 October 2014 up to 28 February 2015. Untreated seeds of all three species exhibited a very low germination percentage, indicating that the seeds of all three species were dormant. For all three species, the germination of seeds untreated with GA3 significantly increased as the cold stratification period increased whereas GA3 application was more effective in improving germination in P. azorica and F. azorica than M. faya seeds. Furthermore, stones of P. azorica that were subjected to outdoor stratification and then transferred to germinate under controlled standard conditions exhibited high and rapid germination.

Effect of sowing date on seedling emergence of species with seeds enclosed in a stony endocarp

ABSTRACT The aim of the present study was to investigate the effect of the natural sequence of temperature conditions between the time of seed sowing and their germination on dormancy release of Prunus avium, P. mahaleb, P. divaricata, P. laurocerasus, P. spinosa, Cornus mas, C. sanguinea, and Celtis australis seeds which are enclosed in a hard stony endocarp. According to their collection date, the seeds (with the endocarp) of the above species were sown outdoor in summer, autumn, and winter and the number of emerged seedlings was counted during the following two springs. For all species, the first sowing date was immediately after seed collection and cleaning. In all species, seedling emergence occurred in early spring and dormancy was released only after the exposure of seeds to specific season conditions. The exposure of seeds of all studied species, except C. australis, to a period of warm temperatures prior to winter was necessary for dormancy breaking and germination. Autumn sowing of P. laurocerasus and C. sanguinea seeds, which were collected in summer, and the sowing immediately after seed collection of the rest species, resulted in a maximum percentage of seedling emergence in the following spring.

EFFECTS OF COLD STRATIFICATION AND GA3 ON GERMINATION OF ARBUTUS UNEDO SEEDS OF THREE PROVENANCES

Background: Arbutus unedo is a valuable Mediterranean shrub as an ornamental plant as well as fruit tree. Fresh fruits of A. unedo are a good source of antioxidants, of vitamins C, E and carotenoids and also are characterized by the high content of mineral elements. Materials and Methods: The effects of gibberellic acid (GA3) and cold stratification (CS) on seed germination performance were investigated in A. unedo seeds collected from three provenances in the Northern part of Greece. Seeds of each provenance were soaked in solutions of GA3 (500, 1000 or 2000 ppm) for 24 h and subsequently were subjected to CS at 3 - 5°C for 0, 1, 2, and 3 months. Results: Non-stratified seeds of the three A. unedo provenances which were not treated with GA3 solutions exhibited very low germination. However, seed germination was significantly improved after a one-month period of CS. Similarly, the non-stratified seeds of all three provenances became non-dormant after the treatment with 2000 ppm GA3 and they germinated at high percentages. However, in untreated seeds with GA3, after a one-month CS period the seeds of the Pieria provenance exhibited higher germination percentage than that of Rodopi provenance seeds. Furthermore, in non-stratified seeds, the Pieria provenance seeds treated with GA3 germinated at higher percentages and more rapidly than those of the other two provenances. Conclusion: The results indicated that untreated seeds exhibited very low germination at 20/25°C. However, in all three provenances seed germinability was significantly improved by a one-month period of CS or treatment of seeds with 2000 ppm GA3. Furthermore, there was a considerable variability among seed provenances in response to the treatments which were applied.