Larch and fir in planted forest stand of the Precarpathian and the Carpathians regions: silvicultural-biometric characteristics and growth peculiarities

Abstract

In the western region of Ukraine, silver fir (Abies alba Mill.) is a common mainly in the Precarpathians and the Carpathians. Within the natural range it forms high-yielding, predominantly mixed stands. In the area of beech-fir forests, the most productive and steady-state stands are formed by Larix decidua var. polonica and Larix decidua var. sudetica. The best associates of the larch species in this area are Abies alba, Picea abies, Fagus sylvatica. Larch and fir, when growing together in forest stands, are complementary tree components, forming high-productive and resilient forest phytocoenoses. The combination of dark-coniferous and light-coniferous species in one stand provides the most complete utilization of the edaphic potential of the site-conditions type. Therefore, stands with the participation of fir and larch are some of the most high-productive among other stands in the Precarpathian and the Carpathian regions. The main technological elements for the establishment of larch-fir plantations have been determined. A comparison has been made between the average biometric indices of Larix L., Abies alba, Picea abies in artificial stands - the height, diameter and volume of the average tree in conditions of the moist beech fairly fertile fir forests, moist hornbeam-beech fairly fertile fir forests, fir forests, as well as fir-oak forests. It is found that the establishment of forest plantations with the participation of larch and fir is a promising trend in the formation of high-productive multi-storey and stable forest phytocoenoses. When forming high-productive and steady-state plantations with larch, fir and spruce, it is necessary to ensure a 30-40% share of larch in the stand composition. It is found reasonable to establish partial larch cultures by means of the species planting in separate rows or by biogroups among the natural regeneration of native species – beech and fir. Plantations with the participation of fir and larch are noted for high biometric characteristics and significant volume of stemwood where dark coniferous species play the role of accessory species while larch forms non-tapering trunks, growing in maturing stands under site-classes Ia-Ib. Larch in this case always has an advantage over fir in height, which allows it to have successful growth in larch-fir stands. In young stands (30-35 years of age) larch, when growing together with fir and spruce, has an advantage in height in the range of 20-25%, in diameter - 25-30%, in terms of the volume of the average tree – twice. In 41-50 years old stands, larch has an advantage over fir in height by 10-20%. Although in some cases it may lag behind in diameter growth. The analysis of conifers growth course shows that until the age of 30, larch and spruce are characterized by the highest growth rate in height and diameter, while fir begins to make better growth, both in height and in diameter, after 40 years of age.

Keywords

• forest plantations
• average height and diameter
• stemwood volume
• Larix L.
• Abies alba Mill.