Leaf-Scale Study of Biogenic Volatile Organic Compound Emissions from Willow (Salix spp.) Short Rotation Coppices Covering Two Growing Seasons

In Europe, willow (Salix spp.) trees have been used commercially since the 1980s at a large scale to produce renewable energy. While reducing fossil fuel needs, growing short rotation coppices (SRCs), such as poplar or willow, may high impact on local air quality these species are known amounts of isoprene, which can lead production tropospheric ozone (O3). Here, we present long-term leaf-scale study biogenic volatile organic compound (BVOC) emissions from Swedish managed site with aim providing information seasonal variability in BVOC during two seasons, 2015–2016. Total seasons were dominated by isoprene (>96% mass) and monoterpene (MT) ocimene. The average standardized (STD, temperature 30 °C photosynthetically active radiation 1000 µmol m−2 s−1) emission rate for was 45.2 (±42.9, standard deviation (SD)) μg gdw−1 h−1. Isoprene varied through season, mainly depending prevailing light, where measured peaked July 2015 August 2016. STD MTs 0.301 (±0.201) h−1 MT decreased spring autumn. sesquiterpenes (SQTs) 0.103 (±0.249) h−1, caryophyllene most abundant SQT. SQTs both Non-terpenoid compounds grouped other VOCs (0.751 ± 0.159 h−1), containing alkanes, aldehydes, ketones, compounds. Emissions all groups towards end season. more sun-adapted leaves upper part plantation canopy emitted higher rates MTs, compared shade-adapted lower canopy. On hand, part. Light response curves showed that ocimene α-farnesene increased light but only leaves, did not emit α-farnesene. An infestation Melampsora spp. likely induced of, e.g., hexanal nonanal 2015. results this imply upscaling model approaches should account seasonality also include position parameter allow better estimates regional global budgets ecosystem emissions.