Common ash (Fraxinus excelsior L.) in Ukrainian forests and its successful natural regeneration

Viktor Tkach,Volodymyr Luk’yanets,Oleksii Kobets,Maksym Rumiantsev,Serhii Sydorenko,Svitlana Pozniakova,Iryna Obolonyk

doi:10.2478/fsmu-2020-0012

Abstract

Abstract The natural distribution area of common ash (Fraxinus excelsior L.) in the forests of Europe and Ukraine has been determined through the analysis of scientific works of Ukrainian and foreign researchers. According to the reference materials on the current state of Ukrainian forests (25 administrative regions), it is established that ash forests cover an area of about 150,000 ha or 2.4% of the total area of the country’s forests. Among them, common ash stands account for almost 87% or 130,000 ha; the rest are stands of introduced ash species, namely F. pennsylvanica Marsh., F. americana L., and F. lanceolata Borkh. The average age of ash stands is 59 years. Only 6.4% (8,300 ha) of the total area of ash forests is covered by pure ash stands, and the remaining area (93.6% or 121,700 ha) are mixed ones. It is revealed that the optimal natural and climatic conditions for the emergence, preservation and successful growth of natural regeneration of ash trees are fresh and moist fertile sites (rich in minerals) with well-drained soils, the light of at least 5–6% of that on an open space, and without abundant live ground cover. The highest number of seed regeneration of ash, about 7,000–8,000 stems ha−1 on average, was found under the canopy of mixed (ash share in the composition was 10 to 20% by stock) old (over 100 years old) stands with a relative density of stocking of 0.7–0.8. Promoting the natural seed regeneration of ash trees can be an effective way of increasing the sustainability of such stands and will ensure their preservation in the forests of Ukraine and in deciduous forests of Europe as a whole.

Highlights

Common ash (Fraxinus excelsior L.) is one of the 30 main forest-forming species in the forests of Ukraine (State, 2016)
We investigated pure ash stands of different ages and relative density of stocking within the specified regions
Within Ukraine, the largest areas of forests with common ash predominating in the composition are in Vinnytsya (14,200 ha), Sumy (12,800 ha), Luhansk (12,300 ha), Kirovohrad (11,900 ha), and Cherkasy (11,500 ha) administrative regions, and the smallest ones are in Kherson (100 ha), Zaporizhzhya (700 ha), Ivano-Frankivsk (1,300 ha), Chernivtsi (1,400 ha), and Dnipropetrovsk (1,500 ha) regions

Summary

Introduction

Common ash (Fraxinus excelsior L.) is one of the 30 main forest-forming species in the forests of Ukraine (State, 2016). Nearly 130,000 hectares (87%) are dominated by common ash; the remaining area is covered by stands with introduced ash species (Matsiakh & Kramarets, 2014) This area is significant because, for example, in Greece, the ash area is only 200 hectares or 1.5% of the country’s forest area (Boiko et al, 2012); it is 14,000 hectares or almost 1% of the total forest area in Latvia (Liepins et al, 2016), 15,400 hectares or 0.4% in Belarus (Domnenkov et al, 2014), 19,200 hectares or 10% in Ireland (Wellock et al, 2014), about 40,000 hectares or 1.4% in the Czech Republic (Giagli et al, 2018), about 90,000 hectares or 1.0% in Poland (Boiko, 2007), 250,000 hectares or 2.4% of the total forest area in Germany (Enderle et al, 2017). Fraxinus excelsior is a tree species whose natural range is spread across most European countries (Figure 1). The natural range of F. excelsior is almost the same as that of the pedunculate oak (Quercus robur L.) (Dobrowolska et al, 2011)

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