Examinations on knots – techniques of plant connections
One of the key techniques of the Baubotanik is the encouragement of plants to intergrow to a physiological unit and a mechanical strong junction by connecting them in a specific manner. The qualification of different fusion methods and the impact of the tree type onto the results of the intergrowth is been examined in current experiments. Therefore, exemplarily common forest and park trees with different anatomic features (e.g. Zerstreut- and Ringporer) and ecological behaviour patterns (e.g. pioneer and climax species) were chosen.
During these experiments the plants were cut at the point of contact: partly in a way comparable to the finishing process of ablactation and partly by being pressed onto each other without further treatment with various joining means. The latter complies the conditions for natural knots which occure often at roots and more rarely also at limbs that incidentally touch each other.
Several phases of these intercrescence processes could be documented on a macroscopic level as well as by microscopic cuts: At first, often a mutual enclosing of the intergrowth partners can be observed. Afterwards the bark tissue links by evolving a callus-like tissue in the outer bark area on the very position where the two ingrowth partners meet each other. Partly these junctions are recognizable from the outside; partly they are not seen until the plant is cut. As soon as the tissue of the bark is grown together across bigger areas a partial “fusion” of the wooden bodies emerges which can only be prooved in cross-section. Some locations do not develop such a connection of the wooden bodies. Then leftovers of living or died off bark tissue remain in the knot.
A successful intercrescence can be proclaimed as soon as during the described process less bark tissue is being embedded and both ingrowth partners share the same annual rings in the following years. Such a result could be reached with several species, e.g. plane-trees, willows and birches, whereas for example with robinias trees nearly no intercrescence could be obtained by the choosen connection methods. A connection between the anatomy of the bark tissue and these results can be assumed.
Part of the PhD intentions of Ferdinand Ludwig, supervised by Prof. Dr. Gerd de Bruyn (IGMA) and Prof. Dr. Thomas Speck (PBG Freiburg)
Scholarship of the DBU
- Experimental area:
Research station for horticulture Hohenheim