Terpene levels in the wound reaction zone in Norway spruce bark 14 and 35 days after <i>Ceratocystis polonica</i> inoculation and baseline levels in uninoculated bark on day 14 and 35.

<p>Based on a weighted average of the number of attacks and extent of gallery construction by <i>Ips typographus</i> trees were classified as susceptible (114.4±70.3 (SD) attacks and 1.5±1.0 m beetle galleries m⁻² bark; n = 5) or resistant (1.1±2.6 beetle attacks and 0.02±0.04 m beetle galleries m⁻² bark; n = 6). Intermediate trees had 31.6±16.8 attacks and 0.2±0.26 m beetle galleries m⁻² (n = 9).