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Characterization of defoliation conditions within a boreal Montane forest ecosystem |
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| Authors: | John A. Brockhaus Siamak Khorram Robert Brack Michael V. Campbell |
| Affiliation: | 1. Forestry Dept. and Computer Graphics Center , North Carolina State University , Raleigh, North Carolina, 27695–7106, U.S.A.;2. Computer Graphics Center, Forestry Dept. and Dept. of Elect, and Computer Eng., , North Carolina State University , Raleigh, North Carolina, 27695–7106, U.S.A.;3. Plant Pathology Dept. , North Carolina State University , Raleigh, North Carolina, 27695–7106, U.S.A.;4. Radian Corp. , Research Triangle Park, North Carolina, 27516, U.S.A. |
| Abstract: | Landsat Thematic Mapper (TM) digital data acquired in the fall of 1988 and digital elevation model (DEM) data were evaluated for use in characterizing the spatial distribution of defoliation conditions within the boreal montane spruce‐fir ecosystem in the Black Mountains (Mtns.) of North Carolina. Correlation coefficients between the TM waveband data and field estimates of defoliation taken from 22 one hectare field plots were low (0.10 to ‐0.54). TM band four (near infrared) was the only waveband found to be significantly correlated with needle loss. Defoliation was also shown to be significantly correlated with digital elevation and aspect data. A multivariate linear regression model predicting percent defoliation was developed from the TM, elevation, and aspect data for the 21 field plots. In addition to having a high R2(0.85) the model was shown to reliably predict defoliation conditions throughout the ecosystem. A color‐coded classified image depicting the spatial distribution of defoliation conditions within the study site was generated by applying the model to the TM and DEM data. |
| Keywords: | Rural-urban migration Nearest neighbour analysis Percent impervious Remote sensing Neighbourhood environment Bangkok Thailand |