. Successional status of subalpine fir in the Cascade Range. Forests and forestry Cascade Range; Fir Cascade Range; Abies lasiocarpa. va beds have also suffered severe .image. Over 80-percent mortality i as observed in a mature stand owing on the West Crater lava >w in the Wind River drainage southwest Washington. Signi- I :ant mortality has also been ob- rved in other lava beds, partic- U arly at lower elevations. Dnceivably, aphid outbreaks could e iminate subalpine fir from local- i ed areas. In closed, mixed stands, ie aphid will hasten replacement ' subalpine fir by more tolerant >e
. Successional status of subalpine fir in the Cascade Range. Forests and forestry Cascade Range; Fir Cascade Range; Abies lasiocarpa. va beds have also suffered severe .image. Over 80-percent mortality i as observed in a mature stand owing on the West Crater lava >w in the Wind River drainage southwest Washington. Signi- I :ant mortality has also been ob- rved in other lava beds, partic- U arly at lower elevations. Dnceivably, aphid outbreaks could e iminate subalpine fir from local- i ed areas. In closed, mixed stands, ie aphid will hasten replacement ' subalpine fir by more tolerant >ecies. Greatest impact of the phid appears to be on the pio- sering ability of subalpine fir — I lose instances where the fir in- ides lava beds, talus slopes, old ;aver marshes, etc. Adversities of e physical environment — already msiderable in these situations — e greatly magnified by the aphid. * Iso, the aphid's habit of settling i terminal buds inhibits new owth and reduces the possibility seed production, further reduc- i g effectiveness of subalpine fir in •Ionizing nonforested land and aintaining its tenuous hold in me areas. Drtunately, mortality is seldom mplete in an infested area. Sup- •essed trees and poor-site trees e far less sensitive to aphid in- stations than was once believed, ven in areas where mortality is 3avy, a few large trees nearly ways escape attack, because of iance, local environment, or pos- bly genetic characteristics. But e most significant characteristic infestation patterns is that at- cks are most abundant and most ;rious at lower elevations. Sub- pine fir above 5,500 to 6,000 feet rarely attacked, and a wide zone left between timberline and the festation area. Here, it appears, iccession will proceed normally, ithout interference from the bai- rn woolly Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations m
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Keywords: ., bo, bookcentury1900, bookcollectionbiodiversity, bookleafnumber17
