We present spring and summer volatile organic compound (VOC) emission rate measurements from Norway spruce ( Picea abies L. Karst) growing in a boreal forest in southern Finland. The measurements were conducted using in situ gas-chromatograph with 1 to 2-hour time resolution. The measurements cover altogether 14 weeks in years 2011, 2014 and 2015. Monoterpene (MT) and sesquiterpene (SQT) emission rates were measured all the time, but isoprene only in 2014 and 2015 and acetone and C 4 -C 10 aldehydes only in 2015. The emission rates of all the compounds were low in spring, but MT, acetone and C 4 -C 10 aldehydes emission rates increased as summer proceeded, reaching maximum emission rates in July. Late summer means were 29, 17 and 33 ng g(dw) −1 h −1 for MTs, acetone and aldehydes respectively. SQT emission rates increased during the summer and highest emissions were measured late summer (late summer mean 84 ng g(dw) −1 h −1 ) concomitant with highest linalool emissions. The between-tree variability of emission pattern was studied by measuring seven different trees during the same afternoon using adsorbent tubes. Especially the contributions of limonene, terpinolene and camphene were found to vary between trees, whereas proportions of α- and β-pinene were more stable. SQT emissions contributed more than 90 % of the ozone reactivity most of the time, and about 70 % of OH reactivity during late summer. The contribution of aldehydes was comparable to the OH reactivity of MT during late summer, 10 %–30 % most of the time.