Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Investıgatıons On The Causes Of Oak Tree Declıne In Belrad Forest

In this century, in the beginning of the eighties, increased damages in oak stands occurred in several countries and were ascribed to a complex of different diseases caused by biotic and abiotic factors. Similar damages symptoms have also been appeared in Turkish oak forests.

In this study, healthy and declined sessile oak (Quercus petrea (Mattuscha) Liebl.) stands were compared by taking forest floor and soil samples in Belgrad Forest-Istanbul. Soil samples were taken from four different soil depths (0-10 cm, 10-30 cm, 30-60 cm and 60-100 cm). Penetration, soil acidity (pH), electrical conductivity, organic carbon (Corg), total nitrogen (Nt) and sand, silt and clay rates were determined on soils of each stand. Unit weight (kg/ha), electrical conductivity, organic matter and total nitrogen content were investigated on forest floor samples. Thus, possible causes of oak decline were tried to search regarding these characteristics.

As a result, some forest floor properties (unit weight (kg/ha), pH and organic matter content) show significant difference between healthy and declined stands. Other forest floor properties (electrical conductivity and total nitrogen(Nt)) did not show significance in comparision. Sand, silt and clay rates, total nitrogen and penetration were not significantly different in all soil depths. Electrical conductivity only in 30-60 cm depth, and organic carbon content only in 0-10 cm depth differ significantly between healthy and declined stands. Except 60-100 cm soil depth, soil acidity was significantly different in all soil depths up to 60 cm (0-10 cm, 10-30 cm and 30-60 cm), and declined stand have significantly higher soil pH than healthy stand.

In conclusion, it was estimated that some investigated soil and forest floor properties were significatly different between healthy and declined stands.. However, oak decline is ascribed to a complex of different damages caused by biotic and abiotic factors. For this reason, further researches on several biotic (insect, fungi, etc.) and abiotic (drought, frost, possible climate fluctuations, air pollution, etc.) factors will be able to reach satisfied results.

DİKTAŞ Dursun ,

Danışman :Prof. Dr.Sedat AYANOĞLU(Danışman)

Anabilim Dalı : Orman Mühendisliği

Programı (Varsa) :

Mezuniyet Yılı : 2006

Tez Savunma Jürisi : Prof. Dr.Sedat AYANOĞLU(Danışman)

Doç.Dr.Aynur Aydın ÇOŞKUN

Doç.Dr.Yusuf GÜNEŞ

Doç.Dr.Kenan OK

Y.Doç.Dr.Hüseyin AYAZ