Author(s): SHIGO ALEX
Reviewed by Thomas H. R. Hall
There will not be many arboriculturists or urban foresters in the temperate regions of the world who have not been influenced by the fundamental research carried out by Alex Shigo during his career in the Forest Service of the United States Department of Agriculture. His patient and methodical examination of decay patterns in the woody tissues of trees has revealed the mechanism of wound responses, indicating biochemical processes which isolate the invading organisms. No longer are trees treated like human beings to whom poultices, ointments and all sorts of medicines are applied to assist and encourage healing. Wound sealants are quite rightly relegated to nothing more than placebos whose only function is cosmetic. The concept of barrier zones isolating infection is epitomised in compartmentalization and walling off. Arboriculturists who have headed the findings of Shigo's research, require no further evidence to demonstrate the validity of his teaching.
Through 135 photographs selected from his many dissections, his tree biology concepts and particularly their relevance to branch pruning are demonstrated. The schematic representation of actual specimen branching (photographs 39, 40 and 41) will in all probability be regarded as the most important single advance in the understanding of tree morphology. Die-hards, have, and will continue to pooh-pooh these findings and conclusions, but all they have to do is to consider and understand the pictorial evidence presented in this title which has been compiled by Alex Shigo and his two eminent European colleagues. After digesting the pictoral evidence, only a stubborn person would remain unconvinced.
This title must surely be essential in every arboriculturist's armour of tree protection. In their hands it will be a gospel of tree care, but horticulturists, landscape architects and foresters must be able to interpret its contents to the planners and administrators who are responsible for the enforcement of Tree Preservation Orders and other constraints designed to protect the tree component of the country's environment.
The American english of the captions is irritating, but on no account should it be condemned — there is no reason why the captions cannot be rephrased without diminishing their impact and to suit the level of the audience. The Danish editors could have adopted the Oxford Dictionary spelling, for example defence instead of defense.
It is unfortunate no one in Britain could have followed up what undoubtedly is an arboricultural scoop which has been achieved by Niels Hvass and Klause Vollbrecht with the generous cooperation of Alex Shigo. There can be no better punch line to this book than that opposite Photograph 30 — 'Treatments that prevent or break boundaries destroy the defence of Trees.'