Select issue
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
1950-1959
1940-1949
1926-1939
Acta Forestalia Fennica
1992-1999
1984-1991
1974-1983
1968-1973
1953-1968
1933-1952
1913-1932
Articles by René I. Alfaro
Category : Research article
article id 382,
category
Research article
(2005).
Survival-time analysis of white spruce during spruce budworm defoliation.
Silva Fennica
vol.
39
no.
2
article id 382.
https://doi.org/10.14214/sf.382
Keywords:
mortality;
hazard rates;
defoliation stress index;
Cox proportional hazard regression;
Choristoneura fumiferana
Abstract |
View details
|
Full text in PDF |
Author Info
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.
-
Magnussen,
Canadian Forest Service, Victoria, BC, Canada. V8Z 1M5
E-mail:
smagnussen@pfc.forestry.ca
- Alfaro, Canadian Forest Service, Victoria, BC, Canada. V8Z 1M5 E-mail: ria@nn.ca
- Boudewyn, Canadian Forest Service, Victoria, BC, Canada. V8Z 1M5 E-mail: pb@nn.ca
Click this link to register to Silva Fennica.
If you are a registered user, log in to save your selected articles for later access.
Your selected articles
Send to email
Send to email
Rousi M.,
(1990)
Breeding forest trees for resistance to mammalia..
Acta Forestalia Fennica
vol. 0
no. 210
article id 7657
(remove)
| Edit comment
Nordström E.-M.,
Holmström H.
et al.
(2013)
Evaluating continuous cover forestry based on th..
Silva Fennica
vol. 47
no. 4
article id 1046
(remove)
| Edit comment
Silva Fennica ·
Finnish Society of Forest Science
