Origin of Monoterpene Emissions from Boreal Tree Species: Determination of De Novo and Pool Emissions

Boreal forests are dominated by monoterpenes emitting tree species (Rinne et al., 2009). Traditionally the monoterpene emissions from coniferous tree species are assumed to originate as evaporation from large storage pools (Guenther et al., 1991). Thus their diurnal cycle would depend only on temperature. However, there is indication that a significant part of the monoterpene emission would originate directly from synthesis (e.g. Shao et al., 2001). Such de novo emission would be rapidly labelled with C were the plant fed with CO2 (Figure 1). Thus this method can be used to quantify the fraction of the emission originating directly from synthesis.