Biogenic Volatile Organic Compound (BVOC) Emissions from Various Endemic Tree Species in Turkey

ABSTRACT

Compositions of biogenic volatile organic compound (BVOC) emissions from seven endemic tree species (Troy Fir, Uludag Fir, Cilician Fir, Oriental Sweetgum, Boz Pirnal Oak, Ispir Oak and Vulcanic Oak) in Turkey were determined. Field samplings were carried out in the forested areas using a specific dynamic enclosure system during the summers of 2011 and 2012. The selected branches of tree species were enclosed in a chamber consisted of a transparent Nalofan bag. The air-flows were sampled from both inlet and outlet of the chamber by Tenax-filled sorbent tubes in the presence of sunlight. Isoprene, monoterpenes, sesquiterpenes, oxygenated sesquiterpenes and other oxygenated compounds including sixty five BVOC species were analyzed with a GC/MS system. Temperature, humidity, photosynthetically active radiation (PAR) and CO₂ concentrations were monitored both inside the enclosure and in ambient air. Calculated emission rates were normalized to standard conditions (1000 µmol/m² s PAR and 30°C temperature). Ispir Oak, Oriental Sweetgum and Cilician Fir were the highest BVOC emitters with total normalized emission rates of 19.4 ± 19.2, 16.3 ± 16.1 and 15.5 ± 11.4 µg/g/h, respectively while Boz Pirnal Oak had the lowest emission rate of 0.84 ± 0.68 µg/g/h. Alpha-pinene, beta-pinene, beta-myrcene and limonene were the compounds dominating the monoterpene emission profiles while trans-caryophyllene, isolongifolene, alpha-humulene and copaene were the prominent sesquiterpenes. Predominant oxygenated compounds were also found as eucalyptol, linalool-L and alpha-terpineol. As reported in the literature, coniferous and broad-leaved species were predominantly monoterpene and isoprene emitters, respectively. Oxygenated compounds were the third most prominent BVOC group and sesquiterpenes had relatively lower contributions for all species.