Ukrainian University of forestry and Wood technology

  Parks of Lviv region

by  Nataliya  Imshenetska

 “Phytocoenotic structure of park plantations of Lviv region and the guidelines of their improvement”

Modern structure of park phytocoenosis

The park plantations are represented both by stocking species of subnemoral, nemoral and boreal zones of Southern hemisphere and by typical autochthonous species in this region. 

 Dominant species are Euro-Asian and Euro-Asian- Southern African origin species (63 species). They are characterized by cosmopolitan, holarctic and panboreal types of natural habital of 16 species. That is, park phytocoenoses are formed mainly at expense of plants of wide-ranged geographic and ecological natural habital. In general, 133 species of higher plants which refer to 37 orders, 47 families and 100 genes . In general, park flora of investigated Lviv region is characterised by specific representation of families : Rosaceae (11 species), Asteraceae (6 species), Poaceae (5 species), Fabaceae (6 species).

 On the basis of direct gradient analysis of flora composition of park phytocoenoses depending on closeness of wood stand canopy it was established that the most variety of new growth, brushes and lianas are observed at closeness of crowns 0.5-0.8. New growth of Acer platanoides L. and Acer pseudoplatanus L. is found most frequently. Its density and projective covering practically does not depend on closeness of canopy crown. The similar tendencies are peculiar for Quercus borealis Michx, Fraxinus lanceolata Borkh., Crataegus monogyna Jacq., Fagus sylvatica L., Tilia cordata Mill., Quercus robur L., Sorbus aucuparia L.  

Crown closeness 0.6-0.8 is favorable for Acer saccharinum L., Fraxinus excelsior L., Robinia pseudoacacia L., Prunus divaricata Ledeb. Other 18 wood species are found occasionally in the park phytocoenosis. 

 The brush storey is formed mainly by Sambucus nigra L., which often forms thick brushwood (nearly 30% cover) in low and intermediate thickness wood stands. Only in thick plantings (0.9-1.0) it is found much more rarely.

 Loose groups under canopy of intermediate thickness wood stand can be formed also by Swida sanguinea (L.) Opiz., which creates considerably tight biogroups in the clearing. The species Ligustrum vulgare L., Symphoricarpus albus Blake, Sambucus racemosa L. are found under canopy more rarely. The other 17 species of brushes are only occasionally found under canopy of park phytocoenoses.

In the grass covering the most frequently observed are populations of Geum urbanum L. (4th stability class) , Impatiens parviflora DC. (3rd stability class), Urtica dioica L., Aegopodium podagraria L., Dactylis glomerata L. It may provide the basis for considering of these plants as diagnostic ones at determining of plant associations by floral principle of Brown-Blanke.

Fairly often are found the coenopopulation Salvia glutinosa L., Poa pratensis L., Anthriscus nemorosa (Bieb.) Spreng., Galeopsis pubescens Bess., Achillea millefolium L. p.p., Poa nemoralis L. Other species, in particular Lysimachia nummularia L., Potentilla erecta (L.) Raeusch., Glechoma hederacea L., Ranunculus acris L., Pulmonaria angustifolia L., Holcus mollis L., Galeobdolon luteum Huds., Geranium robertianum L., Carex sylvatica Huds., Dryopteris filix-mas (L.) Schott, Equisetum sylvaticum L. (mostly forest type) are met considerably rarely, which is a consequence of de-silvatization of urbanized medium. Species Trifolium sativum (Schreb.) Crome, Vicia cracca L., Cirsium vulgare (Savi) Ten., Tussilago farfara L. penetrate the composition of park phytocoenoses with little closeness of crowns. Twenty-six more species of grass plants were found very rarely. Among them the interesting discovery is Epipactis atropurpurea Rafin. — rare species from orchid family which is protected by the Red Book of Ukraine.  

 Summing up the material of investigation of condition of park phytocoenoses we came to conclusion that park plantings are plant groups of mixed (artificial and natural) origin of considerable coenosis formation. Floral composition of park phytocoenoses is formed at the expense of regenerative posterity of introducents and autochthonous species of forest and meadow flora. Availability of flora typical for forest and meadow autochthonous associations in composition of park phytocoenoses is an evidence of their close genetic connection with natural phytocoenogenesis. Considerable content of ruderal species in composition of phytocoenoses of park planting testifies to the definite level of denaturalization and desylvatization processes. The park phytocoenoses, irrespective of peculiarities of artificial forest stand, are characterized by essential space similarity in forming of under-canopy hypersynusia.   

The wide spectrum of various factors of horizontal structure of park phytocoenoses of different composition, closeness and age were covered by cartographic research. Analysis of such cartographic materials testifies that under-canopy mosaic of plant cover is visibly adjusted with relevant structure of forest stand canopy and phytocoenotic situation at the adjacent territories.

 Frequent phenomenon under canopy of forest stand of different composition and closeness is forming of elder-avens-sage grass-brush complex of grass with a great number in natural renovation Quercus borea­lis, Quercus robur, Fagus sylvatica, Acer platanoides, Acer pseudoplatanus.   

The older park phytocoenoses (100 and older) form the under-canopy structure of plant cover of analogous type, but they are characterized by more deep processes of sylvatization. The elder complexes of under-canopy plantation together with Galeobdolon luteum, Aegopodium podagraria, Urtica dioica, Hedera helix L are the  evidence. 

The ecological analysis of more widely spread floral elements shows that edaphotopes of investigated parks are represented preferably by subor and sudubrava types with different levels of moisture supply. In general the under-canopy flora of park phytocoenoses should be considered as megatrophic. The forming of under-canopy flora is affected to a great extend by light requirements of specific flora species, which is demonstrated by the spreading of coenopopulation of under-canopy flora depending on solar conditions. 

The statistical analysis of spreading of coenopopulation in park phytocoenoses showed that under canopy of forest stand the powerful hypersynousias are formed by such kinds of species as Geum urbanum, Sambucus nigra, Swida sanguinea, Impatiens parviflora, Urtica dioica, Aegopodium podagraria, Dactylis glomerata, Salvia glutinosa. The most stability is peculiar to Geum urbanum. The spreading of such hypersynusias depend on composition of forest stand (Table 1).

Table 1  

Spreading  of hypersynusias in park plantations different in composition