XI WORLD FORESTRY CONGRESS Antalya, Turkey, 13 to 22 October 1997
	VOLUME 2, TOPIC 9 SUMMARIES OF VOLUNTARY PAPERS RESTORATION OF PROTECTION FORESTS IN THE BAVARIAN ALPS Dietmar Brinkmann 1 The paper contains information on the condition of protection forests in the Bavarian Alps, the goals and ameans of restoration efforts, the results after the first 10 years. 1 Assistant Secretary, Bavarian Ministry for Food, Agriculture and Forestry, Posotfach 22 00 12, 80535 Munich, Germany. Facsimile: (49 89) 21822351; E-mail: info@stmelf.bayern.de THROUGHFALLANDSTEMFLOWINAMONTANEEASTAFRICAN RAINFOREST Johan Uebel 1 The Ulugurus form one of the major stream source areas in Tanzania. Over the last century large areas of the mountain range have been deforested as a result of the expansion of peasant agriculture. In 1909 the German administration declared 277 km2 of the upper part of the range preserved. The Uluguru Mountain Integrated Soil Conservation Project (Lulandala 1992) includes miscellaneous soil conservation methods aiming at mitigating the streamflow soil erosion from the catchments. The results will be evaluated within the Catchment Forest Project. Throughfall consists of direct throughfall, crowndrip and stemflow. The high spatial and sometimes temporal heterogeneity of tropical forest canopies require elaborate sampling designs. An additional water input of so-called horizontal precipitation (cloudwater) condenses on the leafage of the forest canopy and may contribute to hundreds of mm per year in forests subjected to fog and/or clouds. The objective of this minor field study is to estimate net precipitation in the upper, forested part of the Mlali catchment, a mainly north-west facing catchment in northern Ulugurus, close to Morogoro town. Thirty aluminium troughs, ten on each site, were placed in fixed positions within the forested part of the catchment. The forest is mainly to be regarded as two-storey with generally dense undergrowth and epiphytes abundant on all three sites. Gross rainfall was obtained from two similar troughs outside the forest. Stemflow was measured on 15 trees in connection with the throughfall measurements, by use of longitudinally cut hose-pipe. Between 23 April and the 3 June 1995, mean throughfall was 920 mm for the three sites, which corresponds to 96% of gross rainfall. This result is congruent with other studies on throughfall in rain forests. The used methodology gives reliable data and thus a satisfactory experimental design for throughfall collection. The largest amount of throughfall was recorded on site No. 2 (1 500 m a.s.l.) in the middle of the catchment where selective cuttings for firewood occur frequently. Hence the typical two-storey structure of the rain forest is less pronounced on this site, which might explain the larger amounts of throughfall due to lesser canopy interception. Estimating the extent of canopy interception and evaporation losses require daily values of temperature and wind speed at canopy level. These meteorological data were not possible to obtain within this study. Site No. 3 was placed close to the edge of a ridge and the highest situated (1750 m a.s.l.) and probably most cloud-exposed site in the study area. However, recorded throughfall only amounted to 90% of gross rainfall. This is most likely a result of the absorbing capacity of the large amounts of epiphytes at this altitude. The large difference in collected stemflow between site No. 1 and No. 2 cannot be explained by differences in precipitation. A relevant explanation is difficult to find but the great discrepancy is most likely caused by site and tree specific structural differences, i.e. tree and diameter distribution, vertical stratification and branching geometry. The tested methodology for throughfall collection has been proven reliable and functional for long-term measurements. To be able to relate stemflow to crown area, all trees within a plot should be sampled. 1 Swedish University of Agricultural Sciences, Dept. of Forest Resource Management and Geomatics EFFECTS OF A REGULAR SELECTIVE CUTTING ON STREAMFLOW CHARACTERISTICS OF ORTADERE EXPERIMENTAL WATERSHEDS IN MATURE OAK-BEECH FOREST ECOSYSTEMS NEAR ISTANBUL, TURKEY A.Nihat Balci1, Necdet Özyuvaci1, Süleyman Özhan 1 Calibration equations for streamflow and water yield between the control (W-I) and treatment (W-IV) of watersheds as an integral part of the Ortadere paired experimental watersheds in Belgrad Forest are presented. The effect of 11% removal of the standing volume by regular selective cutting in old-growth oak-beech forest ecosystems was discussed. Correlation and regression coefficients of the calibration equations were found to be very highly significant. The gross variation in water yield immediately after the treatment was detected as the difference between measured and calculated values. Net increase in water yield in certain months (March, April and June) as the difference between the gross increase and the confidence limit for single values were found to be significant. Streamflow hydrographs based on daily flows for these months were developed. Keywords: Paired watersheds, water yield, hydrograph, interception loss. 1 Professor of Watershed Management, University of Istanbul, 80895 Bahceköy-Istanbul, Turkey. Facsimile: (90 212) 3233405 PROBLEMS RELATED TO LAND USE IN THE WATERSHED OF OMERLI (ISTANBUL) Cemal Fidan 1 Only building of water reservoirs is not sufficient to supply water demands of a city. Besides, protection of the watersheds of the reservoirs is very important for this purpose. Thus, the water problem of Istanbul has not been solved yet in spite of building many reservoirs due to insufficient protection measures. For example, the southern and western parts of the watershed of the Omerli water reservoir which is located in the Kocaeli peninsula, 28 km from the city centre of Istanbul, have bben occupied by illegal urbanization. During the urbanization activities, the vegetation cover in the watershed was destroyed. As a result of this, the water storage capacity of the water reservoir has been reduced by erosion. On the other hand, a wrong afforestation policy such as changing the natural deciduous species to coniferous in the watershed areas has caused a reduction in the amount of water filling up the reservoir reduce due to interception. In addition, illegal buildings without purification facilities pollute the reservoir lake. This matter not only increases the expenses of cleaning of water but also threatens human life. The department which is responsible for the protection of the watershed of the Omerli water reservoir cannot prevent illegal settlements and apply the improvement plan due to bureaucracy. The problems related to the Omerli water reservoir have been generally caused by corruption in state departments and by political pressures. Therefore, it is not possible to solve the problems by application of the laws and regulations without removing the political pressures. Keywords: Erosion, pollution, land use, immigration, protection. 1 Southeastern Anatolia Forestry Research Institute, 23049 ElaziX, Turkey. THE ROLE OF FORESTS IN AVALANCHE CONTROL Halil Gerçek 1 Avalanches can be defined as the mass movement of snow cover on the bare areas of steep slopes by internal and external forces. Beginning from old times, forest cover has been accepted as the best tool for preventing this mass snow movement, and people living an the foothills established protection forests against avalanches. Generally, a healthy and dense stand of trees is considered as the best protection against avalanches, but how tree species stabilize the snow on steep slope is not clear, actually it is a common observation that denuded or bare slopes have more frequent avalanches than abundantly forested ones. In fact, a dense forest cover cannot resist the tremendous force of large snow masses in motion. Hence to control huge snow masses that start above the timber-line zone, structures must be installed above this zone, as well as in the area to be forested. Keywords: Avalanche control, forestavalanche interaction. 1 Forest Engineer, Research Assistant, Faculty of Forestry, University of Istanbul, 80895 Bahceköy-Istanbul, Turkey. Previous Section Next Section   Download the Pdf file for this topic (195 K) What is a Pdf file ?   Back to Top of the page
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