Antimicrobial peptide. Detected at higher levels in needles and twigs from canker-resistant seedlings than in needles from canker-susceptible plants. During summer, detected on cankered, healthy and marginal bark. During winter, detected at lower levels in cankered bark and bark from the canker margin than in healthy bark (at protein level). In summer, present at higher levels in older needles and twigs than in tissues from the current year. In winter, detected at high levels in both older and current-year needles and twigs. By wounding and by methyl jasmonate.