DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 7-10/1975 str. 49 <-- 49 --> PDF |
bala lužnjaka, odnosno 12,2 m3/ha, ali i 56 stabala crne johe sa 50 m3/ha. I ovaj podatak ukazuje na poremećaj — pored ostalog — u zoni rizosfere (zamočvarenje uslijed nemogućnosti otjecanja vode jer je cijeli odjel kao kaseta čije nasipe čini cesta), drvna masa iznosi 308 m3/ha u dobi od 88 godina. Struktura sastojine je narušena i može se reći da je tu antropogeni faktor odigrao vidnu ulogu u stvaranju uvjeta koji su doveli do sušenja lužnjaka. U zajednici hrasta lužnjaka s velikom žutilovkom i drhtavim šašem {Graf. 6 i Tab. 6) — inicijalna — vodni režim s periodičnim poplavama (uglavnom za vrijeme mirovanja vegetacije) je vrlo povoljan i sušenja hrasta lužnjaka u proizvodnom dijelu sastojine nije bilo. Drvna masa iznosi 392,2 ms/ha u starosti od 88 godina. Sastojina je normalnog obrasta. U zajednici hrasta lužnja i običnog graba — terminalna — (Graf. 4 i Tab. 4) osušilo se 4 stabla lužnjaka s drvnom masom od 7,2 m3/ha. Drvna masa iznosi 423,8 m3/ha u dobi 77 godina. Obrast je normalan, a struktura nije narušena. Iz prikazanih rezultata — iako su na malom broju pokusnih ploha i relativno kratkom vremenu istraživanja — vidljivo je da narušavanjem samo jednog od edafskih činilaca dolazi do poremećaja, a uz djelovanje i nekih bioloških stvaraju se preduvjeti za propadanje jedne od naših najvrijednijih vrsta nizinskog područja hrasta lužnjaka. Summary INFLUENCE OF THE HEIGHT AND FLUCTUATION OF THE GROUNDWATER TABLE ON THE DYING OF PEDUNCULATE OAK (Quercus robur L.) These investigations on experimental plots were carried out by means of probes down to depth of ca. 7 m. Along with the usual stand description the duration of floods (number of flooding days), the number of standing trees died back and their volume were recorded. From detailed results of investigations (groundwater level in probes and structure of stands) it is visible that during the investigations there died back on the experimental plot — in the initial coenosis of the Slavonian forest (Pedunculate Oak forest with Genista elata and Carex brizoides) — 14%» of the growing stock of Peduculate Oak in the management unit »Josip Kozarac«, and 1°/» in the management unit »Žutica«. In the optimal community of the Slavonian forest during the investigations there died back on the experimental plot 4 °/o of the growing stock in the management unit »Josip Kozarac«, and 7%> in the management unit »Žutica«. The plant- sociological optimum is represented by the community of Pedunculate Oak with Genista elata and Carex remota (Genista elatae — Quercetum roboris caricetosum remotae Horv.). In the terminal coenosis, i. e. in the forest of Pedunculate Oak and Hornbeam (Carpino betuli-Quercetum roboris typicum Rauš) there died back during the investigations on the experimental plot 15 /« of the growing stock of Pedunculate Oak in the management unit »Žutica«. These result suggest — although obtained in a relatively short interval of investigations — that the most suitable water regime was in the management unit »Josip Kozarac« in the forest of Pedunculate Oak with Genista elata and Carex remota. This forest is exposed to typical periodic floods. There dried up 12 standing trees of Pedunculate Oak in the productive part (layer) of the stand with a volume of 13.8 m3/ha out of a total growing stock of 416.0 m3/ha. Neglected were trees from the understorey. The dried-up trees were of d = 32.2 cm and h = 26.6 m, while the |