broj: 11-12/1997
pdf (30,0 MB) |
|
||||||||||||||
| PRETHODNO PRIOPĆENJE | ||
| Prpić, B., Seletković, Z., Tikvić, I. | UDK 630* 919 + 171.3 (001) | |
| On the Influence of the Sava - Danube Canal on Forest Ecosystems pdf HR EN | 579 | |
| Summary: A part ofeastern Slavonia where the mute ofthe Danube-Sava canal is envisaged, stretches over the basins oftwo rivers: the Danube and the Sava. With the exception ofthe Nuštar elevation, it is aflat terrain in which the dijferences in the micro-relief amount to several meters only. The lowland forests ofthe region are characterized by numerous forest communities whose diversity is conditioned by the micro-relief and the water supply. The life of these forests is crucially dependent on groundwater. During the growing period, abundant supplies ofvvater are ensured by the roots of trees reaching down to groundwater levels. It is a knownfact that tree species growing in lowlandforests need larger guantities ofwaterfor transpiration than they receivefrom rainfalling in the vegetationperiod. Hygrophytic trees, such as the pedunculate oak, narrow-leaved ash, black alder, and white willow transpire between 400 and 700 mm water in the growing period. In the Spačva forest basin the annual precipitation is about 600 to 700 mm, ofwhich one halffalls in the vegetation period. Without the additional groundwater, lowlands forests would not be able to grow. These forests contain three different groups of forest ecosystems. These are: 1. Forests of pedunculate oak and common hornbeam grovving on the elevated parts ofthe micro-relief, 2. Slavonian forests of pedunculate dtik in lower micro-relief positions. Before the river Sava was regulated, these forests were regularly flooded, and 3. Forests ofnarrow-leaved ash and forests of black alder in the lowest positions in which water is retained over the largest part oftheyear. During July, A ugust and September the water recedes, thus makingpossible the growth of forest trees. In ali three groups ofsites and their forest associations, water is the dominant ecological factor. Forest ecosystems čame into being when plant and animal species merged and adapted to certain site conditions, the most important being water in various forms: precipitation, flood, or groundwater. Over the centuries, water and other site factors have had a constant and regular influence on, and have determined the development of a particular forest ecosystem. Every change in water conditions causes a disturbance in the forest ecosystem. Hydrological conditions in the lowland forests ofeastern Slavonia depend on the network ofwaterways. In the Danube river basin, it is the river Vuka with its tributaries, and in the Sava one, it is the Bosut with its tributaries. The Spačva forest basin and other lowlandforests are situated in the lowest parts ofthe region. Thus, they are constantly supplied with water, either in the form ofsurface or groundwater, which enables the pedunculate oak and other lowland tree species to transpire abundantly. The importance ofwaterflows far the supply oflowland forests with water is very high. With their floods, but also with "keeping" the groundwater in the region, thev play a crucial role in the sense ofa water gradient. These most valuable lowland forests ofCroatia are directly dependent on the micro-relief floods and groundwater. A large number oftree species and relatively numerous forest communities have allfound their place within a narrow range ofheight differences. Their complexity makes them highly susceptible to mutual and unpredictable synergetic action ofthe existing factors. These forests have reached their full potential precisely under specific ecological conditions, and can only štand very small digressionsfrom the usual site conditions. Ifsite conditions change, these forests become unstable. The hydrological conditions in these forests are suited to the growth of pedunculate oak and other loivland forest species. Each disturbance causing groundwater levels to drop or rise more significantly, or surface water to stagnate in the forest area, would have an unfavourable impact on forest trees. In order to preserve the lowland forests in the Spačva basin and the forests directly affected by the envisaged Danube-Sava canal runningfrom Vukovar to samac, it is necessary to maintain the present regime ofsurface and groundwater in the region. As available data on the existing state of groundwater are not sufficient to determine the limits far these forests, a number ofpiezometersshould be set up so that steps toprotect the forests can be recommended. The total value ofthe affected forest complex, which covers an area ofover 46,000 ha and contains about 14 million square meters ofgrowing stock, exceeds 2 billion DM in terms ofraw material and energy, while its ecological and social value is priceless. Should the assessment ofthe state of forests and forest sites show the NECESSITY to correct the plan ofthe Danube-Sava canal, a possibility to do so must beprovided. | ||
| IZVORNI ZNANSTVENI ČLANCI | ||
| Trinajstić, I., Franjić, J., Samardžić, I. | UDK 630* 181.1 + 188 : 630* 173.5 + 174.7 (Abies alba Mill.) 001. | |
| About the Importance of the Discovery of the Species Equisetum sylvaticum L. (Equisetaceae) for Understanding the Autochthonism of the Silver Fir (Abies alba Mill, Pinaceae) in Požeško gorje pdf HR EN | 593 | |
| Franjić, J., Škvorc, Ž. | UDK 630* 422 (Quercus Cerris L) 001. | |
| Frost-crack in Some Oak Species (Quercus L., Fagaceae) on Krndija and Dilj (Slavonia, Croatia) pdf HR EN | 599 | |
| PREGLEDNI ČLANCI | ||
| Pičman, D., Pentek, T., Mikić, B. | UDK 630* 686 + 383 (001) | |
| The use of Personal Computers in Planning and Drawing up Plans for Forest Roads pdf HR EN | 609 | |
| Turkulin, H., Jirouš-Rajković, V., Grbac, I. | UDK 634.0 814.1 + 634.0 842 (001) | |
| Surface Durability of the Wood Building Constructions pdf HR EN | 617 | |
| Piškorić, O. | UDK 630* 902 (001) | |
| ´Works´ - a Magazine of the Croatian-Slavonian Management Society 1847 - 1852 pdf HR EN | 631 | |
| STRUČNI ČLANCI | ||
| Rauš, Đ., Španjol, Ž., Španjol, B. | UDK 630* 188 + 249 : 630* 156 (Quercus ilex L.) | |
| Scientific and research work in the educational-experimental forest facility of Rab pdf HR EN | 645 | |
| Dimitrov, T. | UDK 630* 432.0 | |
| History of the Canadian Forest Fire Danger Evaluation System Development and the Possibility of its Application in Other Countries pdf HR EN | 657 | |