Ame. Kellner et al., Chronological dating of high-elevation dead and dying trees on northern Vancouver Island, British Columbia, NW SCI, 74(3), 2000, pp. 242-247
We analyzed tree rings to determine the time of death for 18 moribund and d
ead trees used as roosts by bats on northern Vancouver Island. We crossdate
d 29 increment core samples with tree-ring chronologies of living trees to
estimate when the trees died. After they die, yellow-cedar (Chamaecyparis n
ootkatensis) trees deteriorate slowly and remain standing for as long as 20
0 years. In contrast, few western hemlock (Tsuga heterophylla) and western
white pine (Pinus monticola) snags persist longer than 100 years. The ages
at which our sampled trees died were highly variable, with western white pi
ne, western hemlock, and yellow-cedar exhibiting the narrowest to widest ra
nge of ages, respectively. Our findings highlight the long persistence of s
nags in high-elevation coastal forests and the centuries of ecological serv
ice that these trees provide to snag-dependent wildlife.