The fourth level of research uses a combination of the precise geometry of the stem with detailed information about the tree's internal structure. , Previous levels of analysis are combined with device supported tests, like the pulling test or acoustic tomography of the stem. Invasive procedures (e.g. penetrograph) can be used as well. Stability analysis can therefore be verified by several complementary methodological procedures, thus providing the highest possible level of accuracy.
The Adbian Device Testing tool provides professional arborists with the highest detail about stability of valuable trees. The combination of geometric analysis with the outputs of device-supported tests brings increased accuracy of the resulting stability calculations. Even seemingly unavoidable preventive tree felling can thus be averted. By taking into account factors, many of which may have escaped the previous phases of the survey, the resulting opinion on tree biomechanics is much more accurate. Therefore, significantly more detailed and effective stabilisation measures can be proposed.
The Adbian Device Testing method is designed and developed to increase the accuracy of surveys conducted using acoustic tomography or pulling testing, mainly on veteran and valuable trees. The effective synthesis of modern techniques allows the arborist to analyse more closely trees that might be destined for felling if device-supported tests were routinely used.
Also in the case of this level, the safety coefficient value is the key information, which address the stability of the tree in a given location. The outputs from standard device-supported tests (resistance to breakage and uprooting of trees) are refined by means of geometric analysis and their use is also made possible for trees with significantly altered trunk geometry.
The three-dimensional model allows one to visualize the size and structure of the tree in its growth context. For more advanced levels, the 3D model includes detailed documentation of the tree stem condition at the time of the field survey, possibly enriched by the results of the analysis of internal structures obtained through device-supported tests.
The safety coefficient is a value expressed as a percentage that defines the ratio of the strength of the supporting structures(especially the trunk) in relation to the stresses generated in them as a result of horizontal loading by strong winds. A safety factor value of less than 100 % indicates that the tree is insufficiently compensated for the conditions and may pose potential risk of failure. Results of the calculation of the safety factor cannot be used on their own without expert interpretation and the overall contexts evaluated by a qualified arborist.
In addition to the safety coefficient and the analytical 3Dmodel, the collected data can be used for other valuable outputs. These include a volumetric analysis indicating the volume of biomass to be processed if the tree is felled, or a summary of the ecobenefits, i.e. the benefits of the tree to the environment. The range of reports is continuously expanding.