Efficient data assessment of canopy density with the help of vertical photographic exposures
Coch, T. | Bertiller, R. | Trachsler, B.(ETH Zentrum, Zuerich (Switzerland). Departement Umweltwissenschaften)
From the point of view of silvicultural and nature protection the canopies of forests represent an important characteristic value. However, conventional forestry methods do not allow for a differentiated ecological assessment of the changed situation of radiation following light tending interventions. The method presented here enables the collection of exact and reproducible values on the actual density of the canopy from the ground, which calls for no specialist demands on workers or equipment. The paper describes the technology of vertical exposures for both analogue and digital photographic technology. In addition, we present a specially developed programme, which allows the automatic evaluation of the digital canopy exposures. We give two examples for areas of application of the method (finely structured map of trees along a water course and documentation of forestry intervention for the resumption of traditional middle forest management). The presented methodology enables an objective assessment of measures to manage the conditions of light in forests (e.g., special forest reserves), which is significantly superior to a visual assessment with regard to accuracy and reproducibility.
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