Survival-time analysis of white spruce during spruce budworm defoliation
Mortality and defoliation (DF%) in 987 white spruce (Picea glauca (Moench) Voss) trees were followed from 1992 to 2003 during an outbreak of the spruce budworm Choristoneura fumiferana (Clem.) in 15 white-spruce-dominated uneven-aged stands in the Fort Nelson Forest District near Prince George, Brit...
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ftdoajarticles:oai:doaj.org/article:d0344cabbf0e4fe1942c61ae26071614 2023-05-15T16:17:48+02:00 Survival-time analysis of white spruce during spruce budworm defoliation Magnussen, Steen Alfaro, René Boudewyn, Paul 2005-01-01T00:00:00Z https://doi.org/10.14214/sf.382 https://doaj.org/article/d0344cabbf0e4fe1942c61ae26071614 EN eng Finnish Society of Forest Science https://www.silvafennica.fi/article/382 https://doaj.org/toc/2242-4075 2242-4075 doi:10.14214/sf.382 https://doaj.org/article/d0344cabbf0e4fe1942c61ae26071614 Silva Fennica, Vol 39, Iss 2 (2005) Forestry SD1-669.5 article 2005 ftdoajarticles https://doi.org/10.14214/sf.382 2022-12-30T21:56:28Z Mortality and defoliation (DF%) in 987 white spruce (Picea glauca (Moench) Voss) trees were followed from 1992 to 2003 during an outbreak of the spruce budworm Choristoneura fumiferana (Clem.) in 15 white-spruce-dominated uneven-aged stands in the Fort Nelson Forest District near Prince George, British Columbia. Four stands were aerially sprayed with Bacillus thuringiensis (Bt). Defoliation and mortality levels were elevated in non-sprayed stands. The relationship between defoliation and survival-times was captured in a Cox proportional hazard model with a defoliation stress index (DSI), diameter (DBH), crown class (CCL), a random stand effect, Bt-treatment, and number of years of exposure to stand-level defoliation (DYEAR) as predictors. The DSI, optimized for discrimination between survivors and non-survivors, is the discounted sum of five lagged DF% values. Survival probabilities were predicted with a maximum error of 0.02. Hazard rates increased by 0.06 for every one point increase in DSI. CCL and random stand effects were highly significant. Bt-treatment effects were fully captured by DSI, CCL, and DYEAR. Article in Journal/Newspaper Fort Nelson Directory of Open Access Journals: DOAJ Articles Fort Nelson ENVELOPE(-122.700,-122.700,58.805,58.805) Silva Fennica 39 2 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Forestry SD1-669.5 |
spellingShingle |
Forestry SD1-669.5 Magnussen, Steen Alfaro, René Boudewyn, Paul Survival-time analysis of white spruce during spruce budworm defoliation |
topic_facet |
Forestry SD1-669.5 |
description |
Mortality and defoliation (DF%) in 987 white spruce (Picea glauca (Moench) Voss) trees were followed from 1992 to 2003 during an outbreak of the spruce budworm Choristoneura fumiferana (Clem.) in 15 white-spruce-dominated uneven-aged stands in the Fort Nelson Forest District near Prince George, British Columbia. Four stands were aerially sprayed with Bacillus thuringiensis (Bt). Defoliation and mortality levels were elevated in non-sprayed stands. The relationship between defoliation and survival-times was captured in a Cox proportional hazard model with a defoliation stress index (DSI), diameter (DBH), crown class (CCL), a random stand effect, Bt-treatment, and number of years of exposure to stand-level defoliation (DYEAR) as predictors. The DSI, optimized for discrimination between survivors and non-survivors, is the discounted sum of five lagged DF% values. Survival probabilities were predicted with a maximum error of 0.02. Hazard rates increased by 0.06 for every one point increase in DSI. CCL and random stand effects were highly significant. Bt-treatment effects were fully captured by DSI, CCL, and DYEAR. |
format |
Article in Journal/Newspaper |
author |
Magnussen, Steen Alfaro, René Boudewyn, Paul |
author_facet |
Magnussen, Steen Alfaro, René Boudewyn, Paul |
author_sort |
Magnussen, Steen |
title |
Survival-time analysis of white spruce during spruce budworm defoliation |
title_short |
Survival-time analysis of white spruce during spruce budworm defoliation |
title_full |
Survival-time analysis of white spruce during spruce budworm defoliation |
title_fullStr |
Survival-time analysis of white spruce during spruce budworm defoliation |
title_full_unstemmed |
Survival-time analysis of white spruce during spruce budworm defoliation |
title_sort |
survival-time analysis of white spruce during spruce budworm defoliation |
publisher |
Finnish Society of Forest Science |
publishDate |
2005 |
url |
https://doi.org/10.14214/sf.382 https://doaj.org/article/d0344cabbf0e4fe1942c61ae26071614 |
long_lat |
ENVELOPE(-122.700,-122.700,58.805,58.805) |
geographic |
Fort Nelson |
geographic_facet |
Fort Nelson |
genre |
Fort Nelson |
genre_facet |
Fort Nelson |
op_source |
Silva Fennica, Vol 39, Iss 2 (2005) |
op_relation |
https://www.silvafennica.fi/article/382 https://doaj.org/toc/2242-4075 2242-4075 doi:10.14214/sf.382 https://doaj.org/article/d0344cabbf0e4fe1942c61ae26071614 |
op_doi |
https://doi.org/10.14214/sf.382 |
container_title |
Silva Fennica |
container_volume |
39 |
container_issue |
2 |
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1766003729893425152 |