Table 2.

Paired t-test results for original leaf area index data (no processing) and data processed using the methods listed. Analyses of variance were conducted prior to t-tests for all methods to estimate the standard errors, with the exception of logarithmic regression. Methods produced LAI estimates significantly different from actual LAI at 0.05-level if t > t-critical.

MethodProcessingMean Estim. LAISample Mean Difference Embedded ImageSE Embedded ImagendftP-valuet critical α = 0.05 (2-tail)
Actual100% destructive harvest3.694n/a0.261*247
≥1 transmissions removed1.1072.5870.4192476.177<0.012.36
130° w/ 62 threshold3.3040.5830.5472161.0650.332.447
130° w/ mixed thresholds2.8711.0160.4862162.0890.082.447
150° w/ 62 threshold3.1020.7850.5412161.450.22.447
150° w/ mixed thresholds2.9490.9380.4672162.0090.092.447
Image processingNone3.7–0.0060.3452470.0170.992.365
Lang method3.0990.4670.2352471.9880.092.365
Ellipsoidal inversion3.2870.4070.262471.5650.162.365
Logarithmic regressionNone3.383–0.3070.18165–1.0170.362.015
  • * Standard error for mean actual LAI, not Embedded Image.

  • Indicates sample mean significants different from zero.