LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD‐GROWTH FORESTS OF ALASKA 1
ABSTRACT: More than 300 landslides and debris flows were triggered by an October 1993 storm on Prince of Wales Island, southeast Alaska. Initiation, runout, and deposition patterns of landslides that occurred within clearcuts, second‐growth, and old‐growth forests were examined. Blowdown and snags,...
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crwiley:10.1111/j.1752-1688.2000.tb04245.x 2024-09-15T18:31:35+00:00 LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD‐GROWTH FORESTS OF ALASKA 1 Johnson, A. C. Swanston, D. N. McGee, K. E. 2000 http://dx.doi.org/10.1111/j.1752-1688.2000.tb04245.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1752-1688.2000.tb04245.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1752-1688.2000.tb04245.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor JAWRA Journal of the American Water Resources Association volume 36, issue 1, page 17-30 ISSN 1093-474X 1752-1688 journal-article 2000 crwiley https://doi.org/10.1111/j.1752-1688.2000.tb04245.x 2024-07-25T04:20:52Z ABSTRACT: More than 300 landslides and debris flows were triggered by an October 1993 storm on Prince of Wales Island, southeast Alaska. Initiation, runout, and deposition patterns of landslides that occurred within clearcuts, second‐growth, and old‐growth forests were examined. Blowdown and snags, associated with cedar decline and “normal” rates of mortality, were found adjacent to at least 75 percent of all failures regardless of land use. Nearly 50 percent of the landslides within clearcuts occurred within one year following timber harvest; more than 70 percent of these sites had hydrophytic vegetation directly above failures. In following the runout paths of failures, significantly more erosion per unit area occurred within clearcuts than in old‐growth forests on slopes with gradients from 9 to 28* (16 to 54 percent). Runout length, controlled by hillslope position within deglaciated valleys, was typically longer in old‐growth forests than in second growth and clearcuts (median values were 334, 201, and 153 m, respectively). Most landslides and debris flows deposited in first‐and second‐order channels before reaching the main stem channels used by anadromous fish. Slide deposits in old‐growth forests were composed of a higher proportion of woody debris than deposits derived from slides in second growth or clearcuts. Article in Journal/Newspaper Prince of Wales Island Alaska Wiley Online Library JAWRA Journal of the American Water Resources Association 36 1 17 30 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
ABSTRACT: More than 300 landslides and debris flows were triggered by an October 1993 storm on Prince of Wales Island, southeast Alaska. Initiation, runout, and deposition patterns of landslides that occurred within clearcuts, second‐growth, and old‐growth forests were examined. Blowdown and snags, associated with cedar decline and “normal” rates of mortality, were found adjacent to at least 75 percent of all failures regardless of land use. Nearly 50 percent of the landslides within clearcuts occurred within one year following timber harvest; more than 70 percent of these sites had hydrophytic vegetation directly above failures. In following the runout paths of failures, significantly more erosion per unit area occurred within clearcuts than in old‐growth forests on slopes with gradients from 9 to 28* (16 to 54 percent). Runout length, controlled by hillslope position within deglaciated valleys, was typically longer in old‐growth forests than in second growth and clearcuts (median values were 334, 201, and 153 m, respectively). Most landslides and debris flows deposited in first‐and second‐order channels before reaching the main stem channels used by anadromous fish. Slide deposits in old‐growth forests were composed of a higher proportion of woody debris than deposits derived from slides in second growth or clearcuts. |
format |
Article in Journal/Newspaper |
author |
Johnson, A. C. Swanston, D. N. McGee, K. E. |
spellingShingle |
Johnson, A. C. Swanston, D. N. McGee, K. E. LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD‐GROWTH FORESTS OF ALASKA 1 |
author_facet |
Johnson, A. C. Swanston, D. N. McGee, K. E. |
author_sort |
Johnson, A. C. |
title |
LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD‐GROWTH FORESTS OF ALASKA 1 |
title_short |
LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD‐GROWTH FORESTS OF ALASKA 1 |
title_full |
LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD‐GROWTH FORESTS OF ALASKA 1 |
title_fullStr |
LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD‐GROWTH FORESTS OF ALASKA 1 |
title_full_unstemmed |
LANDSLIDE INITIATION, RUNOUT, AND DEPOSITION WITHIN CLEARCUTS AND OLD‐GROWTH FORESTS OF ALASKA 1 |
title_sort |
landslide initiation, runout, and deposition within clearcuts and old‐growth forests of alaska 1 |
publisher |
Wiley |
publishDate |
2000 |
url |
http://dx.doi.org/10.1111/j.1752-1688.2000.tb04245.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1752-1688.2000.tb04245.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1752-1688.2000.tb04245.x |
genre |
Prince of Wales Island Alaska |
genre_facet |
Prince of Wales Island Alaska |
op_source |
JAWRA Journal of the American Water Resources Association volume 36, issue 1, page 17-30 ISSN 1093-474X 1752-1688 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1752-1688.2000.tb04245.x |
container_title |
JAWRA Journal of the American Water Resources Association |
container_volume |
36 |
container_issue |
1 |
container_start_page |
17 |
op_container_end_page |
30 |
_version_ |
1810473289273835520 |