An illustrated guide to the state of health of trees
Recognition and interpretation of symptoms and damage

Eric Boa

Diagnostic and Advisory Service
CABI Bioscience
Egham, Surrey, United Kingdom

Food and Agriculture Organization of the United Nations
Rome, 2003

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Preface

Acknowledgements

1 Introduction

Understanding tree health

2 Using the guide

Investigating problems

3 What is tree health?

Definitions and descriptions of key terms

Diseases, damage and disorders

4 Why trees become unhealthy

Causes of ill health in trees

Pest (biotic) influences