Wood-destroying fungi play an important role in nature, because they are the only forms of life capable of reducing wood to its initial constituents. However, they can also be dangerous for people and property, as they can impair the stability and fracture-safety of trees. This book gives detailed information, based on new and original scientific findings, on the examination and effects of the most important species of fungi associated with failure of infected urban trees. In addition, new ways are presented for predicting the advance of decay in the living tree. The subject is illustrated and made easily accessible by numerous colored photos of fungus fruit bodies, defect symptoms, and macroscopic and microscopic pictures of wood decay. A detailed introduction to the fundamentals of wood pathology provides a way into the subjects of applied mycology and tree-care for readers without previous special knowledge.

Interest in trees, whether in our streets, parks or forests, has in- creasedconsiderablyin thelast 20 years or so.One reason for this has been the decline and dying of forests, which caused great concern about our environment during the 1980s. Because ofthe prominenceofthis event,which is nowblamedon abiotic factors, it is all too easyto forget that the life oftrees is also affected by a multitude of biotic factors: viruses, bacteria, fungi and animals. These may have very different relationships with trees, but are usually deleterious. The fungi playa particularlyimportant part, and during the course of their evolution they have developed various abilities and strategies in order to obtain nutrients and energy by decomposing wood. On the other hand, the tree has 'learned' to react to external and internal infections. The various interactions between fungi and trees form the main themeofthis book. In reviewing this new book I was involuntarily reminded of a work by Robert Hartig over a century ago, entitled Die Zerset- zungserscheinungen des Holzes der Nadelbiiume und der Eiche in forstlicher, botanischer und chemischer Richtung, which laid the foundation of mycological and pathological research on wood.

This book describes and verifies external shape laws in nature, not only valid for trees, but also for bones, claws, thorns, etc. It is shown how growing structures repair the disturbed optimum design after wounding and damage has occured. Computer simulation of these load-adaptive growths is used to find an ecological engineering design, characterized by minimum weight and maximum strength. The optimization procedure is already widely used in industry and many technical examples are given.