Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Seasonal Variation of Soil Respiration Under Different Tree Species in Belgrad Forest

Climate change problem, global warming, increasing CO2 concentration in the atmosphere and the related potential change on greenhouse effect cause to considerable scientific commitments to studies on carbon cycle and CO2 in terrestrial ecosystems over the past decades. For these reasons researches on major global sources and sinks of CO2 increased intensively world-wide.

In this study, seasonal change of releasing CO2 from soil to the atmosphere are being wachted under five different tree species which are Sessile oak (Quercus petreae (Matt.) Liebl.), Fir (Abies bornmulleriana Mattf.), Oriental spruce (Picea orientalis L. Karst), Austrian pine (Pinus nigra Arnold) and Scots pine (Pinus sylvestris L.) in Belgrad forest. This research is being focused on the sources of CO2 in the soil (fine root production), and the main factors (soil temperature and moisture) which are effective on the soil respiration. The respiration samples under every species were taken from five sampling points with three replicates. To determine the soil moisture from the place where the respiration samples are placed the soil samples were taken from 0-5 cm soil deep and the soil tempature was measured simultaneously. Fine root samples were collected via steel soil corers from the four main way (for each species 20 sample) of the points where the soil respiration measures were done four times (April, June, October, January) over year with 3 months intervals.

The research results of annual average respiration value were; in oak 1,0929 g/m2/day, in spruce 0,5563 g/m2/day, in fir 0,8809 g/m2/day, in black pine 0,8056 g/m2/day and in scotch pine 0,9869 g/m2/day are being determined. Annual average soil moisture value determined as, in oak %8,11, in spruce %6,32, in fir %7,33, in black pine %7,11 and in scots pine %6,50. Annual avarage soil tempature value, in oak 14,22 0C, in spruce 13,17 0C, in fir 13,75 0C, in black pine 13,07 0C and in scotch pine 12,95 0C are being measured. Annual average fine root values found as, in oak 2,8228 g, in fir 2,0525 g, in spruce 2,5599 g, in Austrian pine 1,1902g and in scotch pine 1,8702g.

In conclusion, the highest annual average soil respiraiton value was found in oak species, and the lowest was in spruce species. The respiration value show the higher relation with moisture value and fine root amounts.