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ŠUMARSKI LIST 5-6/2018 str. 54     <-- 54 -->        PDF

shoot pruning regimes for western larch (Larix occidentalis Nutt.) crown management were removal of 50–75%of the current shoot, while maintaining top height to 4–5 m (Webber et al. 2003). In the same study, to prune to 3 m once a height of 5 m was not suggested. In light of these findings, it was considered that the terminal shoot pruning performed in the young Turkish red pine seed orchards is compatible/similar to the approach of “slightly top pruning at frequent intervals” that is generally applied in young seed orchards. Nevertheless, it was assumed that pruning at different periods of the year instead of pruning only during spring might be a more viable choice for Turkish red pine seed orchards.
With regard to seed orchard management, no significant difference was found in terms of conelet and cone production between the untreated controls and the pruned ramets in the seed orchards that were employed in the study. Conversely, there were differences between the morphologies, and hence physiologies, of individual trees in each of the three seed orchards. In the middle-aged and young seed orchards, the heights of the pruned ramets were reduced by 18% and 21%, respectively, in 2012. While the difference between control and pruned ramets in the middle-aged seed orchard remained stable from 2012 to 2014, it declined in 2015. The difference between the heights of control and pruned ramets in the young seed orchard disappeared almost entirely in 2013, and continued as such until 2015. At the end of the six-year period in the old seed orchard, the difference between the untreated controls and the ramets pruned by three nodes dropped from 202 cm to 117 cm, while the difference between the untreated controls and the ramets pruned by five nodes dropped from 302 cm to 176 cm. Therefore, in all seed orchards, the common outcome of top pruning was that it enabled a reduction of tree height. Miller and DeBell (2013) indicated that top pruning is used in many species, and helps eliminate the need to use man lifts. On the other hand, the observations made over five years on Aleppo pines, which can be crossbred with Turkish red pine naturally, revealed that there was no correlation between height and the female flower and cone production (Matziris 1997). Another study demonstrated that there were no biological constraints that required seed orchard managers to plan for target heights by pruning (Almqwist and Jansson 2015). Based on these findings, to prune the terminal shoots every year in young seed orchards; to prune three nodes in middle-aged seed orchards every three years; and to prune three nodes in old seed orchards in every four years can be applied. For old seed orchards, it was found that a one-time five node pruning may be sufficient, or that the procedure could be repeated at the end of four years. In sum, top pruning can be used at different levels and different periods as a management tool in young, middle-aged and old seed orchards.
CONCLUSION
ZAKLJUÈAK
Top pruning in seed orchards of different ages ensured that heights remained shorter compared to untreated controls by the end of the four-year period. In addition to the reduction in height, a reduction in diameter at breast height and volume index was also observed. Nonetheless, in the middle-aged seed orchard that required further thinning, it was observed that, despite the reduction in height, the volume indices of pruned ramets increased, in contrast to those in the other seed orchards.
In Turkish red pine seed orchards of different ages, mean heights were reduced by 18% to 39%, and the terminal shoot and node numbers were used instead of proportional measurements (due to their ease of application), and no difference between pruned and unprunedrametswas observed in terms of conelet and cone production.
It was concluded that pruning by three nodes could be repeated every four years, or that ramets could be pruned by five nodes in a single application, or pruning five node could be repeated once again every four yearsin the old seed orchard. One-node pruning can be repeated in every three years in the middle-aged seed orchard, and that terminal shoot pruning can be repeated every year in the young seed orchard.
It was seen that in seed orchards where thinning cannot be applied immediately, top pruning can be applicated as an alternative.
The study revealed that top pruning can be used as a seed orchard management tool at different levels and periods, in accordance with the age of seed orchards.
ACKNOWLEDGEMENT
ZAHVALA
The study was generated from a research project (Project number: ANK-029 1620/2008-2019) of Forest Tree Seeds and Tree Breeding Research Directorate (FTSTBRD). Support and assistance of FTSTBRD is gratefully acknowledged. This work was also supported by Scientific Research Projects Coordination Unit of Karabük University. Project Number: (KBU-BAP-16/2-BM-034).
REFERENCES
LITERATURA
Alan, M., 2012: Breeding of Turkish red pine of in Turkey: past, present and future. Kuruluºunun 60. Yılında Ormancılık Araºtırma Enstitüleri: Dünü, Bugünü ve Geleceği Sempozyumu, 7-9 Kasım, Bolu:212-220 (in Turkish with English abstract).
Alan, M., H. Ozler, R. Sabuncu, T. Ezen, B. Calıºkan, N. Ozbedel, 2011: Effects of pruning on strobili of different age Turkish