Dendrochronological sampling with the help of a manual drill is a common practice in temperate forests. However, this is not the case in tropical forests, where there are problems not only with the often unrecognizable annual rings of tropical trees, but especially with their high density and large diameters, which cause permanent damage to the tool. An interesting solution to the problem comes from a scientific team, which also included Professor Miroslav Svoboda from the CULS Faculty of Forestry and Wood Sciences.
Although the study of annual rings in tropical and subtropical areas is quite demanding and therefore relatively rare, they are no less important compared to research on common tree species, and methods to facilitate them are needed. Scientists who have dealt with this issue have managed to find one. They thus offer a new device which, in contrast to conventional core removal tools, is resistant to the physical properties of these woody plants.
The mobile core removal system, consisting of a cutting tool, an extractor, a motor and a support frame, has a drill functionally different from hand drills. In particular, a high-alloy chrome-plated steel milling cutter is used here. In order to avoid overheating due to friction during sampling, the connected sampling tube is designed with a smaller outer diameter than said cutter, thus creating a cooling gap between the tube and the wood cavity. A big plus is also the gasoline drive, which eliminates problems with battery capacity, which are faced by frequently used cordless drills. This device, which can be used to obtain quality samples up to 1.35 meters long with a diameter of 15 mm, also offers other advantages, but nothing is perfect, and it is necessary to mention one of the disadvantages. Undoubtedly, it is the total weight of the device, which is around 23 kg and thus exceeds the weight of conventional drills. However, the structure is easily dismantled and, when properly disassembled, can be comfortably carried by two people several kilometres through the terrain.
"The device has been successfully tested in rainforests on more than two hundred and fifty trees of high densities and diameters, often around three meters, without any damage," adds prof. Svoboda. It should be noted, however, that the aim of this device is not to completely replace the existing one, and as scientists say, it is not even suitable for intensive sampling in very remote areas. However, compared to traditional methods, this is an important advance in the field of tropical dendrochronology.
Krottenthaler, S., Pitsch, P., Helle, G., Locosselli, GM, Ceccantini, G., Altman, J., Svoboda, M., Doležal, J., Schleser, G., Anhuf, D. (2015): A power-driven increment borer for sampling high-density tropical wood. Dendrochronology, 36, 40-44.
prof. Ing. Miroslav Svoboda, Ph.D.
At the Faculty of Forestry and Wood Sciences at the CULS, he completed his doctoral studies in forestry in 2005. Four years later, he received his habilitation from the Faculty of the Environment of the same university as an associate professor in the field of ecology. He received his professorship last year at FLD, where he currently holds the position of Head of the Department of Forest Ecology.
Prepared by: Jakub Málek