The configuration of concentric circles is a specific feature frequently used in forest inventory programmes. Usually there are tree diameter limits set for various radiuses of concentric circles. In the outer part of the plot only large trees are measured, and towards the centre of the plot the diameter limit decreases. To fulfill this particular methodological requirement, Field-Map enables you to define radius of concentric circles and related diameter limits. This can be done using Field-Map Project Manager. In the field, Field-Map checks the radius and the tree diameter and warns you if a tree smaller than prescribed limits is being measured..

The principle of concentric circles is available only for circular plots (see also “Single sized circular plots”).


  1. A map with concentric circles


  1. The principle of concentric circles


A Trees with DBH > 50 mm are measured within a circle with a radius 8 m.

B Trees with DBH > 150 mm are measured within a circle with radius 12.616 m (entire plot).



Setting in Project Manager


For more information see in the Project Manager user guide.


  1. Open Field-Map Project Manager
  2. Click Edit plot segments button



  1. Edit plot segments window appears. Here you can edit segments.



  1. After downloading DBH information from the calliper, Field-Map refreshes the position of trees depending on their breast diameter and checks if DBH is valid for the appropriate circle. When Field-Map finds a problem, a dialog box “Problematic Trees” appears. The user can delete or keep problematic trees.

This window will appear also if you check a data, see chapter Validating database content.