CAN A MORE DISCIPLINED APPROACH TO TREE APPRAISAL INFORM DEVELOPMENT SITE SURVEYS AND TREE PRESERVATION DECISIONS - AND VICE VERSA?

摘要

Some of the benefits gained from applying a rigour of process to tree valuation could be exported to wider forms of tree appraisal in the UK, such as development site surveys. Indeed, surveyors may already use depreciation methods intuitively, but unconsciously, on development sites. The advantage of unconscious usage is that practitioners have a pre-existing familiarity with these broader appraisal methods; the disadvantage of unconscious practice is that the process remains unfocussed and lacking in internal coherence - no 'grammar' of process. Alignment with more universal methods of quality categorisation than those currently employed in UK practice (i.e. British Standard 5837: 2005 Trees in relation to construction), could lead to a greater transparency of process and greater consistency in consultants' reports. Cross-fertilisation with more disciplined appraisal techniques, such as CTLA's Trunk Formula Method (TFM), is proposed, rather than straight substitution by them. A full TFM appraisal may be too detailed an exercise for each individual tree on a development site; nor is the financial valuation of each tree proposed. Rather, the proposal is that the TFM depreciation factors (Species, Condition, Location) inform the future review of BS5837's quality categorisation process, imparting to it, the basic grammar that is currently lacking. Tree officers could also develop this grammar to more readily justify Tree Preservation Order designations, beyond essentially visual criteria, and through the addition of the monetary factors, when seeking high-level fines. Despite 40 years of amenity tree valuation in the UK, arboriculturalists remain singularly unversed in the broader appraisal language. Familiarisation with and adaptation of CTLA methods, which draw upon this grammar, could help expose arboriculturalists to the language and allow them to communicate valuations more universally to the other professions and industries to which arboriculture must increasingly relate.