The spectral reflectance curves give important information about investigated objects. High-resolution laboratory spectroradiometric measurements were used to investigate the spectral reflectance properties of spruce twigs with various foliage loss. The spectral reflectance was measured in the range from 400 nm to 1100 nm wavelength with 2 nm spectral sampling interval. Measurements of spectral reflectance were obtained using a LI-COR spectroradiometer LI-1800 equipped with standard 1/2 mm monochromator exit slit measuring 6 nm bandwidth and its external integrating sphere covered with barium sulphate inside

Results obtained by crown status estimation and branch structure transformation assessment methods are also applicable at forest stand level. By means of these methods we can reconstruct a scheme of probable stress response history for individual trees with possibility to distinguish three different types of stress response behaviour. The goal of our study was to describe a stress response history of single trees and corresponding forest stands, diverse in different level of multiple stress impact, and to localize investigated trees in the stress response scheme