Topic (B6)
Acquisition of stem surface data by the magnetic motion tracker Polhemus FASTRAK
Description
Modelling and understanding the growth of plants requires detailed knowledge and data about the growth processes. One of the most modern methods for obtaining such data is 3-dimensional digitization using a motion tracker device (Polhemus FASTRAK). The device consists of a magnetic field source, a pointer and a CPU for processing. However, normally used in medicine or cinematography, this tool requires unique data acquisition procedures when applied to forestry. Many works exist to evaluate the architectural development of root systems (e.g., Danjon & Reubens, 2008) and crown architecture (Surovy et al., 2011). A relatively new methodology is the use of this technique to gather surface data from a tree stem in order to evaluate curvature, shape and horizontal asymmetry of the stem.
The objective of this work is to acquire skills for working with the Polhemus FASTRAK digitizing device: acquisition, evaluation and processing of the data. The main aim is to evaluate the formation and asymmetry of the trunk for main species of German forests: spruce and beech (others may be included) grown under different conditions (these may include different soil, illumination, competitor presence etc.). In total, around 30 trees from each species, at least 10 in each condition subsample, should be digitized. Based on the results, the candidate should then reflect about possible hypotheses for growth and formation of stems which can later be incorporated into models and tested against more data.
Literature:
- Danjon, F.; Reubens, B. (2008): Assessing and analyzing 3D architecture of woody root systems, a review of methods and applications in tree and soil stability, resource acquisition and allocation. Plant Soil 303: 1-34.
- Surový, P.; Ribeiro, N. A.; Pereira, J. S. (2011): Observations on 3-dimensional crown growth of Stone pine. J. Agroforestry Systems 82: 105-110.
B.Sc. thesis for 1 student / Bachelorarbeit für 1 Studierende(n), Studiengang Forstwissenschaften und Waldökologie.
If you are interested please contact Mr. Prof. Dr. Kurth.