Four young dwarf pine (Pinus mugo Turra) stands was studied from an possible influence of pine shrubs on several herb species point of view. These plots were monitored each year during 1995-2000. A main method used in this study is based on distances between an herb plant and the nearest dwarf pine shrub. A set of these distances was evaluated by special statistical procedure.
The distribution of Hieracium alpinum agg., Pulsatilla scherfelii, Hypochoeris uniflora, Calluna vulgaris and several other herbs was evaluated as affected by young pine plantings: the influence of dwarf pine shrubs on the distribution of all species under study was great. The ecotonal effect in the dwarf pine surroundings is constituted by belt of width about 100 cm (this distance roughly corresponds to dwarf pine height) and is species-specific. This zone often influences positively not only the number of plants of the species concerned but also its flowering intensity. Plant browsing is influenced by dwarf pine shrubs, too.
The vegetation dynamics and growth of dwarf pine are compared among mentioned plots and four older stands (studied between 1981-1997). Changes in vegetation on the older dwarf pine stands was not accelerated very much during years 1981-1995. Greater changes occurred in the period to 1987 than in the next period since 1987. Dwarf pine expansion is fast under favourable conditions. The area increment in younger stands was 6-38% per annum, which corresponds to an annual increase in shrub diameter by ca. 3-18%.
Key words: alpine tundra, Calluna vulgaris, distance method, Hieracium alpinum agg., Hypochoeris uniflora, Krkonoše Mts., Pinus mugo, Pulsatilla scherfelii, shrub-herb influence, spatial structure