Dating Decline and Mortality of Chamaecyparis nootkatensis in Southeast Alaska
Alaska yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) has been declining and dying for a long, but undetermined, span of time in remote and undisturbed forests of southeast Alaska. Aerial photographs indicate mortality was widespread by 1927. The dates of death for individual snags of Alaska yellow-cedar were determined by counting annual rings on 73 western and mountain hemlock trees growing beneath larger, dead Alaska yellow-cedars, and in live callus strips on 46 Alaska yellow-cedars with partial bole death. Average time since death was 4, 14, 26, 51, and 81 years for snags in class I (foliage retained), class II (twigs retained), class III (secondary branches retained), class IV (primary branches retained), and class V (bole intact but no primary branches retained), respectively. Class V snags, which are common on all sites currenty expressing decline, appear to represent the trees initially affected. Snags in a sixth class with deteriorating boles are uncommon and not associated with sites of decline; their death most likely predated the onset of extensive mortality. Because some class V snags died over 100 years ago, these data suggest that extensive mortality began about 1880, and became obvious about 1900-1910--dates supported by historical records. For. Sci. 36(3):502-515.
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