the influence of mountain pine beetle damage on the 1988 yellowstone fires heather j. lynch paul r....

The Influence of Mountain Pine Beetle Damage on the 1988 Yellowstone Fires

Heather J. Lynch

Paul R. Moorcroft

Remote sensing of fire & insect damage

1972-1975

1979-1982

mountain pine beetle damage

covariatesregression coefficients to be estimated

Spatial Logistic Regression Model:

What is the relationship between previous insect damage and the probability of burning in 1988?

burn/no burn

weather

geographic factors

insect damage

latitude

longitude

€

P(burn) =exp(β 0 + βX)

1+ exp(β 0 + βX)

€

β0 + βX

mean95% confidence interval

Palmer Drought Severity Index

A more negative PDSI is associated with more severe drought. Therefore, as we might expect, more severe drought is associated with a higher probability of burning.

(estimated model coefficients)

Resultsafter model selection, 3 variables remained

(=autocorr)

mean95% confidence interval

Results (cont.)

(estimated model coefficients)

northeast-facing aspect

northeast facing slopes are more likely to burn than southwest facing slopes.

mean95% confidence interval

Results (cont.)

(estimated model coefficients)

repeated mountain pine beetle damage

1972-1975

Repeated mountain pine beetle damage of any intensity during 1972-1975 is associated with an increased risk of burning in the 1988 fires.

mean95% confidence interval

Results (cont.)

(estimated model coefficients)

autocorrelation coefficient

The coefficient associated with the strength of auto-correlation is most dominant.

non-spatial model

Left: burn prob. (red = burned) Right: mis-classified pixels (pink)

auto-correlation only

Left: burn prob. (red = burned) Right: mis-classified pixels (pink)

best-fit model with a random border: 61.0%

of all pixels correctly predicted

Left: burn prob. (red = burned) Right: mis-classified pixels (pink)

best-fit model with a known border: 87.3% of

all pixels correctly predicted

Left: burn prob. (red = burned) Right: mis-classified pixels (pink)

mountain pine beetle activity significantly affects the spatial patterning of forest fires, but only after a time lag of ~15 years

mountain pine beetle activity impacts fire risk primarily through a change in stand structure and not as a direct result of increased fuel loading

Conclusions

Publications: Lynch, H.J. RA Renkin, R.L. Crabtree & P.R. Moorcroft (2006).The Influence of Previous Mountain Pine Beetle Activity on the 1988 Yellowstone Fires. Ecosystems 9: 1318-1327.

HyMap (5.7 m resolution, 126 wavelength bands, airplane mounted)

Satellite-derived estimates of forest insect damage

non-photosynthetic vegetation in red