Long-term dynamics of BVOC production, storage and emission in boreal Scots pine

Plants synthesise thousands of biogenic volatile organic compounds (BVOCs) as part of their secondary metabolism. Scots pine (Pinus sylvestris) particularly produces mono- and sesquiterpenes, which are mainly stored in oleoresin in resin ducts. In this study, the monoterpene emission rate from stems was found to increase as a function of increasing resin pressure, which was positively correlated with the air temperature and foliage transpiration rate. Monoterpene synthase activity describes the maximum monoterpene production potential. The seasonal cycle and needle age were observed to explain the majority of the variation in needle monoterpene synthase activities, monoterpene storage pools and monoterpene emissions from shoots. Variation in the monoterpene concentration between seasons, different needle age classes and different trees was observed to be minor. Monoterpene synthase activity was higher in