DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 3-4/2023 str. 35     <-- 35 -->        PDF

higher altitude zones In the higher zone, H3 had germinated approximately 25% more than H7. However, the difference in the germination rate between cone ages in both altitude zones had decreased compared to the 10th day (Fig. 2).
More than 70% of the seeds had germinated for each cone type by the 28th day of the experiment. As the germination period progressed and at the end of the germination period, the difference in the germination rate between cone ages decreased. The lowest germination rates were recorded for H5 and H7 cone types, and L3 and L4 had about 19% higher germination rates compared to the average of cones collected at the higher altitude zone (Fig. 3).
DISCUSSION
RASPRAVA
Like many pine species distributed in the Mediterranean Basin, which is susceptible to fire, red pine also forms a large number of cones, and some of these cones remain on the crown for several years without opening (Verkaik and Espelta 2006). The seeds in the cones that remain closed on the tree can maintain their germination properties for a certain period (Selik 1963; ªefik 1965; Boydak 2004). In fire-susceptible Mediterranean ecosystems, serotinous cone structure is seen as an assurance for the continuation of the red pine species (Neyiºci and Cengiz 1985; Cengiz 1993, Thanos and Doussi 2000; Boydak et al. 2006). Therefore, the seeds kept in these closed cones over a long time make an important contribution to the seed pool for the generation to come in the region after destruction, e.g., a fire event (Fernandes et al. 2019).
In a study on the detection of closed cones in red pine, Çetin (2010) determined that more cones remained closed for a long time in trees at low altitudes (0-250 m). Selik (1963) obtained close germination percentages of 53.7% and 51%, respectively, from seeds of three- and nine-year-old closed red pine cones. In addition, ªefik (1965) germinated seeds obtained from three – six-year-old closed cones and determined that the effect of cone age on the germination capacity of the seeds was very small. Ürgenç and Odabaºı (1971) found that when mature cones were collected from trees and stored for seven years at room temperature without opening, they germinated, and although there was a slight decrease in germination, their germination rate was above 50%. However, there was no difference between the germination of seeds stored at low temperatures and those of closed cones kept at room temperature. The germination characteristics of the seeds are also determinant in the intra-species competition of the future generations in the region and affect the dynamics of the stand at the establishment stage. Germination percentage is widely used to determine the germination characteristics of seeds. The ability of the seed to germinate quickly, i.e., the germination rate, is an especially important issue. The germination rate also determines the intra-species competition of the future generations in the region. Saplings formed by fast-germinating seeds adapt better to environmental growing conditions (Saatçioğlu 1971; Dağlar et al. 2016). Germination rates and percentages affect the dynamics of the forest in the establishment phase, especially in areas where there are long summer droughts (Dunlap and Barnet 1984).
In this study, the highest germination rate (20.5% on the 10th day) was observed in the seeds obtained from 3-year-old cones from the lower altitude zone. During this period, the germination rates of the seeds obtained from the 5-, 6-, and 7-year-old cones in the higher altitude zone remained below 10%. However, on the 14th day of the experiment, the germination rate of the seeds obtained from 3-year-old cones in the lower altitude zone increased to 62.5%. In their study on the species, ªefik (1965) and Çetin (2010) determined that the germination rate of seeds could be increased significantly by stratification processes. An important factor affecting germination is the elevation level at which the seeds are collected (Çetin 2010). Eler (1992) found no missing seeds in closed cones of different ages collected from three different altitude zones (0-400 m, 400-800 m, and above 800 m), and germination rates of 90%, 81%, and 60% were obtained from cones of three consecutive years. Çetin (2010) determined that the germination rate of seeds collected from lower (0-400 m) and middle (400-800 m) elevations was higher than that of seeds collected from higher elevations (above 1200 m). This study determined that the elevation level where the cones were collected was more effective than the cone age in the germination rate values on the 14th day. The results of the study showed that the germination rate of seeds decreased as the altitude and age of the cones increased. The altitude zone where the seeds were collected was more effective in this decrease than the age of the cones. The results of previous studies as well as this study showed that although the germination rates of the seeds obtained from closed pine cones of increasing cone age differed according to their characteristics, they were able to preserve the germination feature at a certain rate. When the closed cones open after a fire and the viable seeds of the species scatter and suitable germination conditions are formed, important contributions are made to the future generations of red pine (Boydak et al. 2006).
Observations and some studies have shown that the viability of these seeds in the cones is generally not affected during a fire, since the serotinous cones are closed during fires. These cones, which are exposed to high heat during a fire, open slowly after the fire and the seeds fall into the soil. When these fallen seeds find a good germination environment in the ashy fire area and reach the appropriate germination temperature after the rains, they contribute to the new germinating generation. Obvious examples of this were seen in our observations at major fire sites in Antalya, Mersin, and Muğla in July 2021.