The limitations of the method
TreeCalc.com can only ever constitute a source of information that is supplementary to the initial visual inspection of a tree. TreeCalc has been developed for experienced users who have had substantial training in arboriculture and, moreover, have basic knowledge of tree statics.
The TreeCalc.com method of estimating how safe a tree is will help users to assess the failure risk of free-standing trees with stem diameters of 40 cm or more. This risk cannot be reliably estimated for younger trees, groups of trees or even stands of trees (e.g. forests).