DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 1-2/1987 str. 69 <-- 69 --> PDF |
fast, accurate and cheap using remote sensing. First a brief description of the remission of the sun radiation from the vegetation canopy, the construction of and the photography with the colour infrared (CIR) film and the use so far of CIR imagery in forestry in the world and in Yugoslavia is given. The way of image formation on the photographs is mostly influenced by the characteristics of the radiation remitted from the surface of the objects on the Earth. The CIR film enables the reproduction of the differences in remmision in the invisible near infrared part of the spectrum, which are considerably greater then those in the visible part. The variabilities in colour on CIR photos are influenced not only by the tree species but especially by the differences in vitality, respective by the damage of individual trees of the same species. An investigation in application of CIR areal photographs (AP-s) for forestry purpose was performed on imagery taken from the forest stands on southern slopes of Medvednica mountain and from town vegetation of Zagreb, Yugoslavia. The pictures were taken at beginning of August at the scale 1:8000, with Kodak Aerochrome Infrared 2443 film. The AP-s were interpreted visually using magnifiers and mirror stereoscope. The forest stands and trees were classified by their colour and other pictorial characteristics after an interpretation key by ground observations has been establish. The key has four classes according the vitality, respectively the grade of the damage of the trees. The interpretation was complemented by densitometric measurements, but an essential improvement was not achieved. The beech (Fagus sylvatica L.), chestnut (Castanea sativa Mill.) and sessiel oak (Quercus petraea Liebl.) in the forest stands and horse chestnut (Aesculus sp.) in the avenues were interpreted. The dependance of the colour on the images on the vitality of the trees has been proved by increment measurements and by the determination of the hydrature condition of the trees using the Shardakow´s method for measurement of the sucking power high of the root swelling living bark. In the conclusion it is proposed to intensify the application of CIR AP-s for the determination of the condition of the forests in S. R. Croatia. KEY WORDS: fotointerpretation, remote sensing, colour infrared aerial photographs, damage of forests. |