Who is the tallest in the land?
Humans, especially Germans, have always had an intense emotional relationship with trees and forests, not to mention the economic importance of wood and, more recently, concerns about the he alth of the forest and global warming. Accordingly, books about trees dominate no shortage.
The depth and richness of the knowledge conveyed in this work surpasses this diversity. Dietrich Böhlmann, emeritus professor of botany at the Technical University of Berlin, has created a compact vademecum for tree lovers. Thanks to its skirt-pocket format – the fine print of which is quite a problem for older eyes – you could easily take it with you on an excursion; but it is neither a guide nor a reference work. It is not arranged alphabetically and does not contain an index. In terms of content, on the other hand, it is almost a textbook.
The detailed table of contents lists numerous sections, some of whose headings are formulated as statements or questions: "Leaves can become thorns through metamorphosis" or "How do the roots orient themselves in the soil?". If you have a specific question for the book, you must have a certain level of expertise - or you will come across so many new and interesting things when searching that it was worth taking a detour.
Ironically, the answer to the question posed in the book's title is difficult to find in this way. You have to know that water transport is the limiting factor for the height of a tree and that this starts in the roots. Then you learn that the tree uses almost the maximum possible leeway in terms of physics.
The book is about the he althy tree. The inclusion of pathology was not possible due to the size.
The major chapters deal with the stem and crown, inner cell structure, root, leaves, reproduction and propagation. Then the author goes into the decay of leaves and wood in the cycle on 17 pages with 21 illustrations. This process, which is particularly important ecologically, shows how intensively Böhlmann devotes itself to such a topic:
In autumn, important components of the leaves are mobilized and drawn back into the trunk and branches, where they are stored over the winter. They are carbohydrates, amino acids and important nutrient elements that are scarce in the soil. The green chlorophyll has to be broken down for the withdrawal of magnesium, which gives the autumn leaves their typical color, which varies according to the tree species.
At the same time, the tree stores unnecessary metabolites in the leaf that is about to fall. A separation zone is now formed in the petiole, which is softened by enzymes. A protective layer is created towards the branch, which blocks the way for harmful fungi to get into the wood after the leaves have fallen.
On the ground, the dry leaves are first eaten by gnawing soil animals. If there is sufficient moisture, microorganisms penetrate through the resulting holes and continue the decay of the leaves. Depending on the substances stored in the leaf, the decomposition happens faster or slower. The color of the autumn leaves can therefore be used to determine the degradation rate.
The complete decomposition and the formation of humus and soil are treated in a similarly detailed manner. The same follows for the decomposition of the dead wood.
For dessert, some superlatives on tree shape and age follow. Who would have thought that among the trees native to Germany, the spruce would reach the highest height at 60 meters? In the summary figure 475, an attainable height of 50 meters is given for the fir. But I myself saw a fir tree 55 meters long, measured with a measuring tape, and Böhlmann knows how to give the location of a fir tree of the same length. The tallest living tree is probably a Douglas fir in British Columbia and not a Sequoia in California. And in terms of longevity, the giant sequoias in the best locations in the Sierra Nevada can probably keep up with the bristlecone pines mentioned by the author. But who wants to find out with the increment borer or (heaven forbid) with the chainsaw?
Böhlmann regularly describes the biological processes that lead to certain phenomena, which makes it much easier to understand. He shows in detail the growth of the different parts of the tree, the adaptation mechanisms of the leaves and roots, the life cycle and the seasonal cycle of the tree. How the basic shape of a leaf can be modified is illustrated using the example of the beech. The role of hormones in growth, the processes involved in pollination and the attraction of insects by the flowers are other fascinating sections.
As a rule, the German text is supplemented by the appropriate scientific terms. This helps those who want to go from here to the technical literature. The many chemical formulas and designations show that life processes are not based on mysterious forces, but on chemistry. In addition, the author cannot deny that he is originally a biochemist, and must also please the reader with certain details, for example that turgorin, a messenger molecule, is the 4th -O-(6-O-Sulfo-beta-O-glucopyranosyl)-gallic acid.
The print and almost 500 illustrations are graphically exemplary. Photos, line drawings, formulas, micro and macro shots provide valuable information about the structure of the tissue, over-typical forms and life processes. A detailed glossary of botanical terms completes the book.
Finally, I have to admit that the pocket-sized skirt is useful. Anyone who owns this book will want to leaf through it in all walks of life to find new and amazing things about the tree and its life.
