期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2006
卷号：XXXVI Part 7
出版社：Copernicus Publications
摘要：Norway spruce (Picea abies /L./ Karst.) growing in montane and/or boreal environment is continuously exposed to the influence of multiple environmental stress impacts. Stress factors increase nutritional demands imposed on a tree, leading to initial destabilization of its functions, followed by normalization and improved resistance or resilience depending on the stress intensity and duration. The objective of this study is to investigate the optical variability in Norway spruce needle categories collected from primary and secondary shoots throughout juvenile (upper) and production (middle) functional crown parts of stress resistant and stress resilient trees. Needles of three past generations were included into the analyses; however, spectral differences due to the leaf ageing were not statistically examined. The needle optical properties, i.e. hemispherical-directional reflectance, transmittance and absorption, of five defined needle categories were statistically tested for their quantitative and qualitative differences within the wavelength range from 505-800 nm. Spectral analyses were followed by laboratory measurements of needle pigment concentration (chlorophyll a+b and total carotenoids) and dry matter content. Results indicated no spectral variability within the observed spruce functional crown parts of one stress class, no matter whether they were stress resistant or resilient. However, significant optical differences were discovered in the visible (green and red) and the red edge wavelengths when comparing needles of primary shoots of two stress response classes. These differences were statistically related to the changes in the concentration of both examined foliar pigments, which proved to decrease in the needles of resilient trees. No significant variability was found within the near infrared wavelengths of tested needles
