Problematics of natural regeneration of native tree species in floodplain forests along Mura river

Obnova nižinskih poplavnih gozdov ob Muri je pomembna tako iz vidika trajnosti in gospodarjenja z gozdovi kot tudi vidika varstva narave. Problematiko naravnega pomlajevanja smo obravnavali v dveh večjih strnjenih predelih ob reki Muri, v Murski šumi in Gornji Bistrici, s skupno površino okrog 600 hektarjev. Analizirali smo pomlajevanje drevesnih vrst v različnih habitatnih tipih gozdov, ki so uvrščeni v območje Natura 2000. V habitatnem tipu 91E0* Obrečna vrbovja, jelševja in jesenovja smo ločeno obravnavali dva podtipa (belovrbovje in črnojelševje), ki se ločita po rastiščno-ekoloških in sestojnih značilnostih. Znotraj habitatnega tipa 91F0 Poplavni hrastovo-jesenovo-brestovi gozdovi vzdolž velikih rek pa smo izločili bolj vlažne, pogosteje poplavljene sestoje od manj vlažnih, ki ponekod že kažejo težnjo k habitatnemu tipu 91L0 Ilirski hrastovo-belogabrovi gozdovi. Za analizo pojavljanja drevesnih vrst v zeliščni in grmovni plasti smo uporabili metodo fitocenoloških popisov in metodo popisovanja mladja. Metodi sta dali razmeroma primerljive rezultate. Z metodo fitocenoloških popisov smo po posameznih habitatnih tipih v povprečju zajeli več drevesnih vrst kot z metodo popisovanja mladja. V vseh tipih oz. podtipih smo v zeliščni in grmovni plasti ugotovili razmeroma majhen delež nosilnih in ciljnih drevesnih vrst. Težave naravne obnove gozdov so v veliki meri posledica neustreznega gospodarjenja v preteklosti, spremembe rastiščnih in hidroloških razmer, povečane gostote divjadi in objedanja pomladka drevesnih vrst, razraščanja invazivnih tujerodnih rastlinskih vrst in zdravstvenih težav ključnih drevesnih vrst. Ugotavljamo, da razvoj vseh obravnavanih tipov gozdov praviloma ne gre v smeri naravne drevesne sestave in v smeri ugodnega stanja ohranjenosti habitatnih tipov (Natura 2000). Ciljno in čim bolj naravno drevesno sestavo v gozdovih ob Muri bomo dosegli le z aktivnim pristopom, ki bo poleg naravne obnove v veliki meri vključeval tudi umetno obnovo z rastiščem ustreznimi drevesnimi vrstami.Regeneration of floodplain forests along the Mura River is important from the viewpoint of sustainability and forest management just as well as nature conservation. The problematics of natural regeneration was dealt with in two larger serried areas along the Mura River, in Murska šuma and Gornja Bistrica, with the total area around 600 hectares. We analyzed the regeneration of tree species in diverse forest habitat types (FHT), included in the Natura 2000 area. In the 91E0* %Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae)% habitat type we separately dealt with two subtypes (Salicetum albae and Alnetum glutinosae subtype), who differ according to site-ecological and stand characteristics. Within the 91F0 %Riparian mixed forests of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia, along the great rivers% habitat type we separated the more humid, more often flooded stands from the less humid ones, that in some places already show a trend towards the FHT 91L0 "Illyrian oak-hornbeam forests." We applied the method of phytocoenological relevés and the regeneration survey method for the analysis of tree species in the herbaceous and shrub layer occurrence. The methods gave relatively comparable results. By individual habitat types, in average we identified more tree species with the method of phytocoenological relevés than with the regeneration survey method. We discovered a relatively small share of key and target tree species in the herbaceous and shrub layer in all types or subtypes. The problems of natural regeneration originate to a great extent in an inappropriate management in the past, in change of site and hydrological conditions, increased game density and browsing of tree species saplings, spreading of invasive alien plant species, and health problems of the key tree species. We realize that the development of all studied forest types does not proceed towards a favourable conservation status of habitat types (Natura 2000). The target and preferably natural tree composition in the forests along the Mura River will be achieved only with an active approach, which will, in addition to the natural regeneration, to a great extent also include the artificial regeneration with the tree species, appropriate for the sites