Water consumption measurements on forest trees by trunk heat balance method

The precipitation amount of a region depends on its geogrophical position on the earth and it does not change substantially. On the other hand the population has an increasing trend in Turkey and people uses the water sources. As a result of this, the amount of fresh water per capita is decreasing. Therefore, management of fresh water resources is a major issue in Turkey. One fourth area of Turkey is covered by forests. Most of the water resources supplying fresh water to the people originates from forested watersheds. Vegetation management practise is one of the instruments used by watershed planners in order to increase water quality and water yield. Hence, the knowledge of the water consumption of trees growing in the forests is very important for watershed planners and decision makers. Forests provide ecosystem services such as soil protection, air cleaning, recreation, wood producting as a raw material, increase water with good quality, water regime regulation, while they use water for growth. When literature on water consumption of trees in Turkey are reviewed, there are no long-term studies conducted in the forest ecosystem that reveal water consumption of forest trees. The aim of this thesis was to determine water consumption rates of one coniferous (Anatolian black pine) and one broad-leaved (sessile oak) tree species growing in sub-humid climate conditions. The field measurements of the thesis was completed between 2016-2017 years and the study site was Atatürk Arboretum in the Belgrad Forest. The daily maximum water consumption of blackpine tree was 76.31 kg that of sessile oak was 162.42 kg. The daily average water consumption of the black pine and sessile oak stands were 1.08 mm and 4.00 mm respectively and they consumed 396 mm versus 908 mm water annually. The results also showed that the stand of black pine transpired %35 of the annaul precipitation while the sessile oak transpired %74.5 of the annual precipitation.