Latvijas platlapju mežu dabisko biotopu struktūra

Abstract

Mežu bioloģiskās daudzveidības saglabāšanā liela loma ir dabiskajiem meža biotopiem. Maģistra darbā pētīta sešu platlapu koku sugu dabisko meža biotopu kokaudzes struktūra un dinamika. Dabiskie meža biotopi sastopami eitrofos augšanas apstākļos, sausieņu un āreņu meža tipos – gāršā, vērī un platlapju ārenī. Mežaudžu daudzveidību atspoguļo sugu sastāvs kokaudzē. Visos dabiskajos mežu biotopos ir liels koku sugu skaits - vidēji 4 sugas. Tikai ozoli un oši ir sastopami tīraudzēs. Būtiskākie dabisko meža biotopu traucējumi ir nosusināšana un nesena ciršana. Analizējot dabisko meža biotopu pavadītājsugu sastāvu, ir konstatēts, ka ozolu un ošu mežos nelielās platībās notiek galvenā stāva atjaunošanās ar to pašu sugu. Šāda maiņa notiek tikai ozolu un ošu audzēs. Ozolu audzēs lielākās platībās kā pavadītājsuga (parasti jaunāka) ir sastopams osis. Ošu mežos piemaisījumā sastopama liepa.

Atslēgas vārdi: dabiskie meža biotopi, bioloģiskā daudzveidība, kokaudzes transformācija.

The natural forest biotopes play a decisive role in the preservance of forest biodiversity. This Master Paper reflects the research of the structure and dynamics of six deciduous tree species natural forest biotopes. The natural forest biotopes have been observed in eutrophic growing conditions, in drought-enduring and expanse forest type: in vast-forests and big-forests. The diversity of forests is reflected by the tree species in the particular growth. Al natural forest biotopes show a large number of tree species - four as the average. Only oaks and ash trees have been observed in pure plantations. Draining and recent felling of the woods are proved to be the most significant disturbances of forest biotopes. While analyzing the contents of the natural forest biotopes' specific accompanying sub-species it has been detected that in oak and ash tree forests of comparatively small areas the main growth renewing changes have been taking place by the same species. This type of change is noted only in oak and ash tree plantations. In a bigger scale oak forest the ash tree is being observed as the main sub-species (most often younger aged). In ashtree forests the linderntree is the usual sub-species.

Key words: natural forest biotopes, biological diversity, tree-plantations' transformation. The natural forest biotopes play a decisive role in the preservance of forest biodiversity. This Master Paper reflects the research of the structure and dynamics of six deciduous tree species natural forest biotopes. The natural forest biotopes have been observed in eutrophic growing conditions, in drought-enduring and expanse forest type: in vast-forests and big-forests. The diversity of forests is reflected by the tree species in the particular growth. Al natural forest biotopes show a large number of tree species - four as the average. Only oaks and ash trees have been observed in pure plantations. Draining and recent felling of the woods are proved to be the most significant disturbances of forest biotopes. While analyzing the contents of the natural forest biotopes' specific accompanying sub-species it has been detected that in oak and ash tree forests of comparatively small areas the main growth renewing changes have been taking place by the same species. This type of change is noted only in oak and ash tree plantations. In a bigger scale oak forest the ash tree is being observed as the main sub-species (most often younger aged). In ashtree forests the linderntree is the usual sub-species.

Key words: natural forest biotopes, biological diversity, tree-plantations' transformation.