engleski

NATURAL REFORESTATION OF PEDUNCLED OAK FORESTS IN CROATIA "YESTERDAY-TODAY-TOMORROW"

Throughout this century the human race, by its management activities, has left, and is still leaving, "traces" of immeasurable consequence with regard to the disruption of the balance of ecosystems. Forests in Croatia and some ecosystems have experienced great changes during the last few decades, which can be seen in the occurrence of forest dieback - drying of forests, loss of increment, disrupted seed production, non-occurrence of natural reforestation of expected tree species, etc. Peduncled Oak forests in the lowlands of Croatia present economically the most important natural resources, and the Peduncled Oak in these forests represents the most significant tree species with regard to management and ecology. The beginning of the disruption of nature in these forests was noticed in the first half of this century with the disappearance of the lowland Elm tree due to dieback. This trend has continued and has today acquired worrying proportions; which is primarily demonstrated in the lack of natural reforestation. For natural reforestation of the Peduncled Oak several conditions have to be satisfied, some of which are more significant than others, such as optimal age of the stand, ratio of tree-species mixture, basal area and stocked forest land, quality and plentiful acorn crop, favourable physical, chemical and biological soil properties, adequately long regeneration time, etc. which today in many ways remain unsatisfied and are not the same as some decades ago. Therefore, because of the foregoing, natural reforestation of these forests remains in the past and planted reforestation has become a reality, which depends on a permanent, from year to year, insufficient amount of acorn both for the needs of nursery production of cultured seedlings and also for direct introduction into the stand. This has been confirmed by a 37-year long investigation of this problem in which a trend of increased consumption can be observed in ten-year periods in the ration 1 : 18 : 62. In addition, we have become increasingly aware of another problem which has appeared from these investigations, and which indicates a very slight decline in qualitative properties - vitality and absolute weight in the last forty years.

natural reforestation; peduncled oak

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