DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 13/2005 str. 29 <-- 29 --> PDF |
S. Matić, I. Anić. M. Oršanić: S1LVICULTURAL TREATMENTS AIMED AT IMPROVING THE ANTI-EROSION ... Šumarski list SUPLEMENT (2005), 17-30 points out that it was the first cleaning in Slavonian state forests. In 1898, Partaš agrees with Kozarac´s theses on oak forest tending and points out that a young oak stand should be cleaned several times and that multiple thinning operations should be applied when the stand reaches adulthood. In 1915,Zezulka writes about the thinning practices in the oak stands in the Posavina region. According to this author, low thinning was an important silvicultural treatment aimed not at obtaining fuelwood but at enhancing the principal stand. He describes thinning in young, middle-aged and old pedunculate oak stands. Pctračić (1919) discusses cleaning and thinning in young developmental stages of ash and oak, as well as the natural selection of trees into diameter and value classes. In his book "On Thinning" Baien (1929) points out: "Maybe we cannot bequeath large reserves of mature forests to our descendents, but we must leave them carefully tended young stands". He believes that thinning practices should be above theoretical discussions. The issue of regeneration has always had an important role in the history of managing pedunculate oak forests in Croatia. The problem of regenerating old oak forests was discussed at the first assembly of the Croatian- Slavonian Forestry Society held in 1846. As seen from Kozarac´s writings (1887, 1886), regeneration of oak was a very important issue. He stressed that management of pedunculate oak forests should be based on natural regeneration. Two methods of natural regeneration of oak forests were used at that period: 1. the "selection cut" method with a 10-15-year grazing ban, 2. the "final cut" method with a five-year grazing ban. The first method involved a gradual, selective removal of all the trees except pedunculate oaks during the 10-15-year grazing ban (a period in which cattle was banned from grazing and feeding on acorns). That period was intended for the oaks to seed the regeneration area. In actual fact, these were incomplete shelterwood cuts (Matić 1996) consisting of the preparatory and the final cut and a regeneration period of 10 to 15 years. According to the second method, a stand was "excluded from use" for five years before being cut. At that time oaks fructified abundantly and frequently, so the regeneration area was well seeded with acorns. After the seedlings and the young plants had emerged, the old stand was cut down. This was a primitive method of regeneration in one cutting treatment and a shortened re generation period of five years. Still, regeneration was natural because it occurred in the previously seeded regeneration area under the crown shelter. The seedlings and the young growth developed under the crown shelter of old trees during the five-year regeneration (and seeding) period. When the crop was poor or tending was absent, narrow-leaved ash or elm would suppress the pedunculate oak, so the old oak stand would be regenerated as an ash, hornbeam or elm stand. P e t r a č i ć (1926) later stated that the shelterwood harvest in pedunculate oak forest should be accomplished in two cuts with a longer regeneration period. The researchers investigating the regeneration of pedunculate oak forests in Croatia (Matić 1996, 1984, Dekanić 1961, Starčević 1990,Đuričić 1986,Petračić 1926, Lončar 1949) agree that the best method to use is the shelterwood method consisting of the seeding cutting operation in two to three cuts and a regeneration period of 6 to 8 years. Any possible artificial regeneration should be executed according to the principles of natural regeneration, which means that before the final cut acorns should be sown or planted and seedlings planted under the crown shelter. The value of silvicultural treatments applied in the management of pedunculate oak forests has been confirmed by practice of many years and scientific research. However, the following problems may occur: 1. the absence of tending the young growth and the young forest in terms of tending intensity and stand area, 2. the absence of first thinning in the young stands after the culmination of height increment several years after the last cleaning, 3. the absence of thinning in the second and the third age class, 4. the maintenance of stands in which dieback and decline have reduced the canopy, especially those in which pedunculate oak has suffered dieback, 5. no recovery of gaps bigger than 0.1 ha, which were caused by dieback of the main tree species, 6. the compartments should be selected more intensively in dieback-affectcd stands in order to give timely presentation of the realistic condition by compartments and to apply timely silvicultural measures (S t a r č e v i ć 2004), 7. the game population density does not accord with stand and site capacity 8. the shelterwood method is favoured over large areas. SELECTION FORESTS A selection forest is considered by many an ideal of non-commercial functions, including the anti-erocommercial forest form capable of providing an array sion and water-protective function. Viewed from this |