Vegetation periods and changes in the Thrace (1965-2011) Trakya’da vejetasyon süreleri ve değişimleri (1965-2011)

The existence and distribution of plants on the earth with one of the most important elements of the natural environment are determined by the abiotic and biotic conditions. Changes that occur in natural conditions and human activities are generally creating a negative effect and many plant species are facing in danger of extinction. One of these conditions, climate is main factor that directly affects the lives of plants and determines the existence and distribution of vegetation as globally, regionally and locally. The greenhouse effect caused by human activities in the last century and the global climate change can have impacts on the existence and spatial changes of plants. In this context, the effects of temperature conditions as the main factor on vegetation are examined according to the certain temperature values and duration. Mean daily temperature values of meteorological stations, which have long term observation record, in the study area, were analyzed statistically. As a result, dates of start, dates of finish and number of days and temporal changes of vegetation period are determined in this period. Extended English abstract is in the end of  PDF (TURKISH)  file . Ozet Dogal ortamin en onemli unsurlarindan olan bitkilerin varligini ve yeryuzundeki dagilisini abiyotik ve biyotik kosullar belirlemektedir. Dogal kosullarda meydana gelen degisimler ve insan faaliyetleri, genellikle olumsuz etki yaratmakta ve bircok bitki turunun nesli tukenme tehlikesiyle karsi karsiya kalmaktadir. Bu kosullar icerisinde iklim dogrudan bitki yasamini etkileyen ana faktor durumunda olup kuresel, bolgesel ve yerel olarak vejetasyon topluluklarinin varligini ve mekânsal dagilisini belirlemektedir. Son yuzyilda insan faaliyetlerine bagli olarak ortaya cikan sera etkisi ve kuresel iklim degisimi bitkilerin varligi ile mekânsal degisimi uzerinde etkili olabilmektedir. Bu cercevede, vejetasyon uzerinde ana etken durumunda olan sicaklik kosullarinin bitkiler uzerindeki etkisi, belirli sicaklik degerleri ve suresine gore ele alinip incelenmistir. Inceleme alaninda uzun donem gozlem kaydi bulunan meteoroloji istasyonlarinin gunluk ortalama sicaklik verileri istatistiki olarak analiz edilmistir. Sonuc olarak incelenen bu donem icerisinde vejetasyon devresinin baslangic, bitis tarihleri ve gun sayilari ile zamansal degisimi belirlenmistir.