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Result of this task shows differences among particular types of forest in tree growth. It maybe interpret as growing site potential or expected tree height of particular dimension.
Requirements:
For that task is necessary to run the stratification by forest development types (see stratification) and to classify trees to diameter classes (see classification).
Procedure:
- Add new task and rename it
- Select “Trees” layer
- Select “Trees.Height, m (Tree_Length_m)” attribute
- Set “m” in the Units combo box and number of decimal places of your choice (e.g. 1)
- Select “Forest development type (Forest development type)” in Stratifier section and tag Use stratifier in output checkbox
- Select “Trees.Diameter class (5 cm)(DiameterClass5)” as classifier
Note: Click Add classifier button, tag “Trees.Diameter class (5 cm)(DiameterClass5)” check box and click OK
- Tag Skip summary line in output check box
- Select Weighted mean and set “Area, ha (RepreArea_ha)” in Weigh. attribute. Set desired Alpha (e.g. 0,05)
- Set “Area, ha (RepreArea_ha)” attribute as Plot weight attribute
- Run the task using Perform button
Comments
Whole plot is assigned to particular forest development type while performing stratification.At the same time the total area of each forest development type is calculated based on existing vector map (shapefile).
Setting attribute ForestDevelopmentType as stratifier increases precision of the output since there is available information about size of the stratums derived from the map of forest development types.
Dimension category is used as classifier
There is no sense for summary line (results for all dimensions together) in this particular task.
Setting weight attribute as representative area points out the different share of the given species group within an inventory plot.
Because the calculation is performed only for the trees above 7 cm of DBH, the including/excluding trees of regeneration segment, hasn’t any effect on the result.
Screenshots
Results:
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