No 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 CO 2 concentrations were monitored both inside the enclosure and in ambient air. Calculated emission rates were normalized to standard conditions (1000 µmol/m 2 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, betapinene, beta-myrcene and limonene were the compounds dominating the monoterpene emission profiles while transcaryophyllene, 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.

Biogenic volatile organic compound (BVOC) emissions from thirty-eight tree species (twenty broad leaved and eighteen coniferous) grown in Turkey were measured. BVOC samples were collected with a specialized dynamic enclosure technique in forest areas where these tree species are naturally grown. In this method, the branches were enclosed in transparent nalofan bags maintaining their natural conditions and avoiding any source of stress. The air samples from the inlet and outlet of the bags were collected on an adsorbent tube containing Tenax. Samples were analyzed using a thermal desorption (TD) and gas chromatography mass spectrometry (GC/MS) system. Sixty-five BVOC compounds were analyzed in five major groups: isoprene, monoterpenes, sesquiterpens, oxygenated sesquiterpenes and other oxygenated VOCs. Emission factors were calculated and adjusted to standard conditions (1000 μmol/m 2 s photosynthetically active radiation-PAR and 30°C temperature). Consistent with the literature, broad leaved trees emitted mainly isoprene while the coniferous trees emitted mainly monoterpenes. Even though fir species are coniferous trees, they emitted significant amounts of isoprene in addition to monoterpenes. Oak species showed a large inter-species variability in their emissions. Pine species emitted mainly monoterpenes and substantial amounts of oxygenated compounds.