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  • Istraživanja strukture sast...
    Barčić, Damir; Dubravac, Tomislav; Ančić, Mario; Španjol, Željko; Ćurić, Petar

    Nova mehanizacija šumarstva, 12/2020, Letnik: 41, Številka: 1
    Journal Article, Paper

    Uloga šuma hrasta crnike nije primarno gospodarska, iako djelomično može biti (ogrjevno drvo, biomasa), ali danas u okolnostima klimatskih promjena izraženija je njihova ekološka i socijalna uloga, posebno zato što prevladavaju šume niskoga uzgojnoga oblika (panjače). Površina uređajnoga razreda panjača hrasta crnike u Republici Hrvatskoj iznosi 21 216,63 ha, od toga je 8351,79 ha u redovitom gospodarenju poduzeća Hrvatske šume d.o.o. Površina od 12 740,18 ha nalazi se u šumoposjedničkim šumama. Zajedničko je obilježje panjača hrasta crnike izostanak bilo kakvih uzgojnih radova u mladosti i tijekom njihova razvoja, premda su u panjačama propisani šumskouzgojni radovi na čišćenju i prorjeđivanju te na obnovi. Budući da su prepuštene spontanu razvoju, razvio se čitav spektar, od onih najkvalitetnijih s relativno visokom drvnom zalihom dobro sklopljenih i suvislo obraslih sastojina pa do onih nekvalitetnih, razbijena sklopa, sa sitnim i kvalitetno lošim stablima male drvne zalihe. Istraživanjem su obuhvaćene samo plohe u okviru međunarodnoga projekta »Man and Biosphere« – MAB (Čovjek i biosfera), plohe Šumarskoga fakulteta te plohe Hrvatskoga šumarskoga instituta. Strukturna istraživanja radila su se u crnikovim šumama i uspoređivana su na trajnim pokusnim plohama s otoka Raba, Brijuna i otoka Mljeta (TPP br. 36, br. 56 i 57, br. 37). Na trajnim pokusnim plohama izoliranima od antropogenoga utjecaja u tijeku su progresivni sukcescijski procesi, iako je zabilježen intenzivan utjecaj divljači na Rabu i na Cresu, što će uvjetovati problem obnove. Sastojine poprimaju izgled jednodobne sastojine, stabilne su i buduća istraživanja trebala bi pratiti daljnju dinamiku razvoja sastojine. Eventualni poremećaji mogli bi biti izazvani ponajviše požarom. The role of holm oak forests is not primarily commercial, though they have some commercial uses (heating wood, biomass). Today, under conditions of climate change, the ecological and social roles of these forests are becoming increasingly important, particularly since this species is predominantly found in low forest forms (coppices). In the Republic of Croatia, the surface area of holm oak coppices is 21,216.63 ha, of which 8351.79 ha are under the regular management of the national company Hrvatske šume d.o.o. (Croatian Forests). Another 12,740.18 ha are within privately owned forests. Holm oak coppices are characterised by a lack of any silvicultural works during the young stages of the forest and during their development, despite the fact that silvicultural works, such as cleaning, thinning and restoration, are prescribed for coppices. Since they are left to develop spontaneously, an entire spectrum of wood is produced, from relatively high wood stock with well formed and sufficiently thick stands, to lesser quality, sparse forms with poor, weak trees of low wood volume. This study was conducted on MAB plots (Man and Biosphere international project) of the Faculty of Foresty, University of Zagreb, and plots of the Forestry Institute. Structural research was conducted in holm oak forests, and compared to permanent experimental plots (PEP) on the islands of Rab, Brijuni and Mljet (PEP nos. 36, 56 and 57, 37, respectively). Comparison with other PEPs (Fig. 9) on the Brijuni Islands and Mljet Island, where the association Fraxino orni – Quercetum ilicis H-ić is also present, gives a broad overview of the succession of this community. Since there was only one measurement for PEP No. 57 (Brijuni Islands), the initial comparison refers to measurements on PEPs No. 36 (Rab Island) and 37 (Mljet Island). Systematic research (ongoing since 1996) on the PEPs is outlined in the studies of Dubravac and Krejči (Tables 4 and 5). The authors examined 12 PEPs and described the structure of holm oak stands therein, with special emphasis on the possibility of applying seed cutting, or transforming holm oak coppices into high growth forest. Thinning experiments were conducted on the experimental plots of the Faculty of Forestry, University of Zagreb, in the period from 2006 to 2014 (results shown in Tables 7 and 8). Progressive succession processes were found to be underway on experimental plots that were isolated from anthropogenic influences. These stands took on a stable, middle-aged form, and future research should continue to monitor the dynamics of stand development. Possible disturbances are most likely to result from fire.