The book is divided into three sections. The first section deals with what trees are, how they evolved, how they are classified, and the nature of wood. The second section is a guide to all the trees in the world. The final section deals with how trees live and their adaptations. The first and third sections are interesting and well worth reading. The middle section takes a bit of getting through if you just try to read the book in order - its descriptive style doesn't seem to quite fit with the explanations in the other sections.
I would recommend this book, but suggest that you read the first and third sections. Then dip into the middle section, concentrating on groups of trees you have a particular interest in, or just read bits at a time.