DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagoðeno pretraživanje po punom tekstu



ŠUMARSKI LIST 3-4/2023 str. 36     <-- 36 -->        PDF

Many studies have determined that, as with red pine, some other pine species produce closed cones and that these cones are opened after a fire. For example, it is stated that the closed cones of Pinus pinaster, which is distributed in fire-prone ecosystems, make an important contribution to future generations by opening and germinating after a fire (Moya et al. 2018). Again, a study conducted with Pinus yunnanensis pine species in 80 sample areas in China found that closed cones were formed in all of the regions where the species grew, but the percentage of closed cones decreased as the age of the closed cones increased. The germination rate of 1- and 2-year-old closed cones in these regions was around 90%. As the age of the closed cones increased, the germination rate of the seeds decreased, with the germination rate of 7-year-old seeds decreasing to approximately 32%. It was determined that the lower-aged closed cones in this region opened and germinated after a fire and played an important role in the regeneration of Pinus yunnanensis forests (Su et al. 2015). The amount of serotinous cones is effective on tree age and silvicultural interventions such as thinning. The ability of the seeds in these cones to maintain their germination feature also depends on the severity and duration of the fire. It was determined that especially after severe fires, the seeds in the closed cones lost their viability and thus, the number of Pinus pinaster and Pinus halepensis saplings decreased. After less severe forest fires, it was determined that the seeds in the closed cones germinated and made an important contribution to the regeneration of the forests. Fernandes et al. (2019), in another study on Pinus halepensis, reported that the number of closed cones might vary according to the age of the stand and the silvicultural interventions applied and that they could be effective in the formation of a new generation after a fire (Verkaik and Espelta, 2006).
No previous study has examined the genetic characteristics of the serotiny status of red pine. However, in a study conducted to determine the heritability of the serotiny status of Pinus halepensis, which like red pine has serotinous properties, the serotiny status showed a significantly narrow heritability of 0.20. Although this species exhibited a high variability within the serotinous population, forests with repeated wildfires contained more serotinous species than those rarely exposed to fire (Hernandez-Serrano et al. 2014). This view is supported by observing that the ecosystems in the Mediterranean Basin where red pine forests showing sertinous features are distributed have been constantly exposed to fire in the past. Although no study has examined the genetic characteristics of the species in terms of serotinous features, this subject has been considered in other pines. For example, in a study carried out to determine the genetic basis of the serotinous cones of Pinus concorta, differences in serotinous characteristics were found in some trial areas, and different genes and ratios were obtained from serotinous cones and non-serotinous cones in some trial areas (Feduck et al. 2015). Thus, although the germination rates and percentages in serotinous cones were slightly lower than for 3-year-old cones, considering that these cones may have different genetic characteristics, the use of the seeds in these cones could have a positive effect on the genetic diversity of red pine forests and the sustainability of forests and their adaptation to global climate change.
CONCLUSIONS
ZAKLJUÈAK
In this study, although the germination rate of seeds obtained from closed cones 3 - 7 years of age was low on the 10th day, more than 50% of the seeds obtained from the lower altitude zone and approximately 40% of the seeds from the higher altitude zone had germinated on the 14th day. Although the germination rates differed among the cone ages at the beginning, this difference in germination values decreased as time progressed. It was determined that the germination rate of the seeds obtained from the 7-year-old closed cones collected at both altitudes was still above 70%. As a result, when these aged cones open after a fire, the seeds dispersed will contribute extensively to re-establishing the forest in burned areas left without any rejuvenation work after the fire, and in steeply sloping areas and in places where it is not possible to establish a forest by human hand. Considering that the closed serotinous cones of other pine species exhibit additional genetic characteristics (Feduck et al. 2015), the use of seeds from these cones to grow saplings and establish forests may provide an advantage in terms of increasing genetic diversity.
REFERENCES
LITERATURA
Anonymous, 2015: Orman Genel Müdürlüğü, Türkiye Orman Varlığı Kitabı. Orman Genel Müdürlüğü Yayınları. Ankara.
Boydak, M., H. Dirik, M. Çalıkoğlu, 2006: Kızılçamın (Pinus brutia Ten.) biyolojisi ve silvikültürü. OGEM-Vakfı Yayınları. 364 s. Ankara.
Boydak, M., 2004: Silvicultural characteristics and natural regeneration of Pinus brutia Ten. a review. Plant Ecology. 171. p. 153-163.
Cengiz, Y., 1993: Sıcaklık ve külün kızılçam (Pinus brutia Ten.) tohumlarının çimlenme yeteneği ve fidan büyümesi üzerine etkileri. Uluslararası Kızılçam Sempozyumu (18-23 Ekim 1993, Marmaris). Orman Bakanlığı Yayını. s. 90-98.
Cruz, O., J. García-Duro, M. Casal, O. Reyes, 2019: Role of serotiny on Pinus pinaster Aiton germination and its relation to mother plant age and fire severity. iForest 12: 491-497.
Çetin, B., 2010: Mersin Yöresinde Kızılçam (Pinus brutia Ten.) Kozalak ve tohumuna ait bazı özelliklerin yükseltiye bağlı değiºimi. Orman Mühendisi Tezi. İ.Ü. Fen Bilimleri Enstitüsü, 185.
Dağlar, C., D. Eºen, B. Çetin. 2016: Screening for metsulfuron methyl phytotoxicity in seed of various pine species. Düzce Ormancılık Dergisi. 12 (2). 34-43 s.