For the past decade, it has been apparent to both of us that a reference text covering all aspects of tree defense mechanisms to fungi was missing, needed and long overdue. Such a book would provide a clear, comprehensive overview of how living roots, stems and leaves respond to fungal pathogens. The need for such a book became in creasingly clear to us from our conversations with each other, as well as from our interactions with students and colleagues who desired a sourcebook containing reviews of morphological, biochemical and physiological aspects of host-parasite interactions in trees. During a field trip sponsored by the Forest Pathology Committee of the Ameri can Phytopathological Society, on a bus from one site to another, we decided to take the responsibility to prepare a book of this type and began to plan its composition. To adequately address the topic of this book as we had envisioned it, we believed that well-illustrated chapters were needed in order to reflect the important advances made by the many investigators who have examined the anatomical and physiological changes that occur when trees are attacked by fungi. We are grateful to Dr. Tore Timell, the Wood Science editor for Springer-Verlag, for supporting our efforts and for providing an avenue to publish such a profusely il lustrated volume."

The oil crisis during the 1970s turned interest towards the utilization of renewable resources and towards lignocellulosics in particular. The 1970s were also the cradle period of biotechnology, and the years when biotechnical utilization of lignocellulosic waste from agriculture and forestry gained priori ty. This was a logical conclusion since one of nature's most important biologi cal reactions is the conversion of wood and other lignocellulosic materials to carbon dioxide, water and humic substances. However, while biotechnology in other areas like medicine and pharmacology concerned production of expen sive products on a small scale, biotechnical utilization and conversion of ligno cellulosics meant production of inexpensive products on a large scale. Biotechnical utilization of lignocellulosic materials is therefore a very difficult task, and the commercial utilization of this technology has not progressed as rapidly as one would have desired. One reason for this was the lack of basic knowledge of enzyme mechanisms involved in the degradation and conversion of wood, other lignocellulosics and their individual components. There are also risks associated with initiating a technical development before a stable platform of knowledge is available. Several of the projects started with en thusiasm have therefore suffered some loss of interest. Also contributing to this failing interest is the fact that the oil crisis at the time was not a real one. At present, nobody predicts a rapid exhaustion of the oil resources and fuel production from lignocellulosics is no longer a high priority."