Arboricultural Consultant

P.G. Biddle

Dr P.G. Biddle, O.B.E., M.A., D.Phil., F.Arbor.A.
Registered Consultant of the Arboricultural Association
Honorary Fellow, Insitute of Chartered Foresters

Review - Andrew Bond

Andrew F Bond MIStructE, DMS, CEng

Review in Geotechnical Engineer, October 2000

Discovering a book which has a quality that makes it stand out from the usual is a great pleasure, especially when it is a book dealing with an apparently mundane topic. These two volumes provide that pleasure, both in terms of their content, which is authoritative and comprehensive, and presentation, which makes excellent use of colour throughout.

Volume 1 covers the causes, diagnosis and remedy of tree root damage to buildings and Volume 2 presents patterns of soil drying in proximity to trees on clay soils. The latter is a research report (beautifully presented) covering three projects involving 60 trees of various species in various soil types. Although both volumes are of value to someone studying this subject in depth, it is the first volume that is of greater value to the practising engineer.

Volume 1 describes the interaction of trees, soils, water, and buildings (Chapters 1-10), the investigations of damage (Chapters 11-16), and remedy and prevention (Chapters 17-20). It deals systematically with all aspects of the problem; the tree; its root system; the soil; seasonal changes in soil moisture content; persistent deficits; the interaction between trees and buildings; and the influence of the weather. The author even finds space to compare the effects of different species and of individual trees and groups, plus other forms of damage by tree roots.

The book goes on to present a strategy for investigating damage covering site investigations of the building, the soil, and the tree; monitoring building movements; diagnosing and predicting heave and recovery; remedial action after damage; and the prediction and prevention of that damage. Finally, the author discusses the legal framework for work with trees and proposes a revised role for the professions.

Each chapter in the book ends with a detailed case study, drawn from the author's consultancy work, which explains a particular problem, discusses the issues involved, and lists the lessons to be learnt.

The author, who is a research forester and arboriculturist with more than 23 years' experience, argues for a radical reappraisal of the methods used to investigate and remedy damage. He comments that the relevant Building Research Digests provide no overall analysis of the subject and the Institution of Structural Engineer's report on Subsidence of low rise buildings has negligible input about trees. His book certainly redresses that situation and, although some of his opinions are controversial, he has undoubtedly made a major contribution to the subject.