International Journal of Forestry Research

Research Article

Identifying Subalpine Fir (Abies lasiocarpa) Attacked by the Balsam Woolly Adelgid (Adelges piceae) Using Spectral Measurements of the Foliage

Table 6

Classification results (%age of individual trees that were correctly classified as infested or not infested with the adelgid) obtained from the discriminant analysis procedure for the SPOT5-HRVIR Band Equivalent Reflectance (BER). Results in the validation samples column were generated by applying the discriminant function developed from a randomly selected training data set to the remaining 33% of the observations ( ). Results in the all samples column were generated by applying the discriminant function developed using the entire data set of 206 trees sampled during the study.
Correctly classified (%)
Model parameters Validation samplesAll samples
SR8483
SR; SWIR8491
SR; SWIR; NDVI8693
The model parameters are SR = (Red/NIR) where Red represents the SPOT-5 BER response in the red region, NIR represents the SPOT-5 BER response band in the near infrared region; SWIR = the SPOT-5 BER response in the shortwave infrared region; NDVI = (NIR – Red) / (NIR + Red).