Digital Flygbildsteknik för Uthållig Skogskötsel - Slutrapport

The objective of this project was to develop methods for estimation of forest stand variables using digital analysis of near infrared air photography, Near Infrared air photography covering an area 200 km northwest of Stockholm was scanned and orthorectified. Methods for digital classification, normalisation of view angle effects and estimation of parameters such as timber volume, stand density, crown coverage, species composition, defoliation and number of dead or dying trees have been developed. Major results were that the functions for normalisation on view angle effects on tree size as viewed from the focal point strongly improved the stand estimates.Timber volume, stand density, species composition as well as the ecological variables were estimated with accuracies comparable to those of subjective field inventory methods. In spite of the photography being of high quality, differences in colour between flight lines gave problems with separation of pine and spruce. This may be solved using post-classification manual editing, but will cause an increase in costs. In the future, digital cameras or calibration lamps within the photograph could further reduce this proble