The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B6b. Beijing 2008 
extra processing based on maximum height does not exclude all 
gaps between crowns. The reason for it is that on each step 
algoryth works on filtered surfaces. 
The general finding based on presented study is that the best for 
assessment of above parameter is to use nDSM with 0.5m 
resolution. For this resolution the highest number of trees was 
detected and height estimation is similar to raster with 0.25 m 
resolution. Raster 0.5 m is four times smaller than 0.25 m 
resolution, so without failure of accuracy we can safe hard drive 
space and analysis time. 
6. CONCLUSIONS 
Main finding from above study is that 0.25 and 0.5 m raster 
resolution are the best for selected forest parameters extraction. 
Model resolution with 1.0 m do have a larger influence on the 
number of recognized trees, which is crucial parameter for 
stand volume calculation based on existing models for polish 
forest. nDSM model is perfect surface for acquisition above 
described parameters. 
As presented in other studies the laser scanner measurements 
show pretty accurate results for tree height estimation. No 
matter if 0.25, 0.5 or 1.0 m raster resolution will be used there 
is no statistically significant difference between their results. 
ACKNOWLEDGEMENTS 
We would like to thank Prof. Barbara Koch from Department of 
Remote Sensing and Land Information Systems, University of 
Freiburg, Germany for cooperation and possibility to use 
software TreesVis for DSM, DTM and nDSM models 
generating. 
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