Scots pine provenance affects the emission rate and chemical composition of volatile organic compounds of forest floor

Scots pine (Pinus sylvestris L.) is an important source of biogenic volatile organic compounds (BVOCs) in the boreal zone. BVOC emission rate and profile affect air quality, climate forcing, plant stress tolerance, and thus the growing conditions of forests. BVOC emission profile of shoots and forest floor, as well as emission rates from forest floor, were studied in a latitudinal provenance experiment with 19-year-old Scots pine common garden in Central Finland. The provenances studied were Saaremaa (SAA, 58 degrees 22'), Korpilahti (KOR, 62 degrees 0'), Suomussalmi (SUO, 65 degrees 10'), and Muonio (MUO, 67 degrees 56'). A chemotype with high proportion of Delta-3-carene, terpinolene, sabinene, gamma-terpinene, and alpha-terpinene was significantly more common for the southern SAA than the northern SUO and MUO provenances. A chemotype with high proportion of alpha-pinene, beta-pinene, limonene, and myrcene was more common in the three northernmost provenances. The main compounds emitted by forest floor were alpha-pinene, Delta-3-carene, and camphene. Similarly to shoot emissions, forest floor emissions from SAA had highest proportion of Delta-3-carene. Average total VOC emission rate from forest floor was 50 mu g center dot m(-2)center dot h(-1) at the end of August. Total emission rates were 65% higher in KOR than in MUO. High emission rates were explained by the high amount of decomposing needle litter and low moss coverage.