How we value & manage trees – challenges for today & tomorrow

This latest issue of the Arboricultural Journal presents three major papers, by Doick et al. (2018) on the highly topical issue of the valuation of amenity trees as public assets, by Ridbäck, Vike, and Dietze-Schirdewahn (2018) on matters of how we place value on (or not), non-native tree species in protected landscapes and taking the example of European silver fir (Abies alba) in Norway, and by Slater (2018), with his latest in the series on “natural bracing”. So we have two contributions on “values” and one on “management” though in practice one leads to the other – or at least should do.

As this editorial was being prepared the sad news arrived of Rodney Helliwell’s recent passing and so it is appropriate that valuation is a key topic in this issue. (We will of course carry a full appreciation of Rodney and his life-long support for the profession and for the journal, in a later issue). In their paper, Doick et al. (2018), provide a detailed review of the CAVAT system and a very useful and timely overview of the “Helliwell system”, i-Tree Eco, and the Council of Tree and Landscape Appraisers (CTLA) approach. With urban tree management continuing to exercise minds across the UK and in wider environments too, local authorities with limited budgets and sometimes few staff have difficult decisions to make. These may relate to planning considerations or to their own tree management policies, strategies and implementation plans. Urban tree issues frequently have long-term implications for the urban environment (townscape or cityscape), for local communities and even for local economies. This situation means that having effective, testable and tested systems to reliably inform decision-makers becomes increasingly vital. The authors note that valuing amenity trees is important for calculating loss of amenity and replacement value. This might be after an incident of wilful or negligent damage, or to help guide aspects of urban forest management such as planning, budget-setting or decision-making. The main focus of the paper is “Capital Asset Value for Amenity Trees” or CAVAT, a tool for valuing amenity trees first presented publicly in 2003. CAVAT has two levels of application (1) the Full Method (used to provide a compensation replacement value for single trees) and (2) the Quick Method (used to determine the value of a population of trees as an asset, for asset management purposes). This is important stuff and the editor welcomes further contributions to the field and examples of worked applications of the various approaches.

Ridbäck et al. (2018), take a very different look at “values” with research on attitudes to old, naturalised but non-native trees in protected areas. Again, with increasing trends towards “novel ecosystems” (Hobbs, Higgs, & Hall, 2013) in many parts of the world, and to “recombinant ecologies” (Rotherham, 2017) in Britain and much of Europe, a consideration of attitudes and values is very pertinent.

In the final paper of this issue, Duncan Slater continues his tour de force on the subject of tree forks, associated weaknesses, failures and related structural issues. Here, we have a detailed account of the diversity and types of forks, of natural bracings, and an effective approach to assessing and prioritising risk and its management.

Ian D. Rotherham
Editor, Arboricultural Journal
[email protected]