Research

The measurement of timber is of central economic importance in forestry and the wood industry. In practice measuring harvested wood is time-consuming and thus expensive. Forestry companies therefore usually rely on the wood industry's measurement lists to determine the exact quantities of wood harvested. In the course of this project, algorithms for the automatic measurement of wood stacks recorded with laser scanners, are going to be developed. The aim is to enable the transparency of timber flows along the supply chain and advance the digitization of it. This will be achieved in three sub-goals: 1. Individual log measurement of higher-value round timber assortments An overview of the quantities of timber harvested and delivered is of particular economic interest in the case of high-value and sawn round wood. For this type of stacked wood, it should be possible to generate measurement results on an individual log basis and thus obtain an overview of diameter and volume distributions, assortment lengths and the total stack volume. 2 Objective determination of conversion factors for energy and industrial wood Various conversion factors are used when converting the gross volume into the net volume. The choice of the factor is usually based on subjective judgement though. By collecting parameters from laser scans, it should be possible to determine an individual conversion factor for scanned wood stacks and thus enable an objective, comprehensible volume determination for energy and industrial wood stacks. 3. feature recognition of stacked logs The composition of tree species and the proportion of lower-value assortments are important factors in the invoicing of wood. However, an exact survey of the volume shares of these assortments is time-consuming outside of sawmills. These variables are therefore usually estimated. Using algorithms developed in this project, the estimation of tree species and value-reducing properties such as wood decay or blue stain will be automated using laser scanning data. This should be possible for energy and industrial wood as well as saw logs. Together with the evaluation of individual log sizes, it should ultimately be possible to create a list of dimensions for stacks of saw logs, as is known from sawmills.

This research project will revolutionize forest inventory throughout Austria in a long-term and sustainable way. Thus, the project is of nationwide relevance . Due to the practical and target group oriented nature of the project, the research results will be available to a broad audience and will provide forest owners, forest enterprises, service providers and authorities with a planning tool for the creation and maintenance of climate-smart forests. The methods to be developed in the project should be implementable as a standard solution for the highly precise and spatially explicit inventory of raw wood reserves and the operational planning of forest enterprises based on it. By combining modern, laser-based field survey methods (partly with commercially available mobile devices such as Apple iPhone and iPad) and remote sensing methods, planning uncertainties of careful and sustainable forest management can be minimized, the productivity of different timber harvesting methods can be predicted and thus the risks and costs of forest enterprises can be reduced. The methods thus contribute to the preservation of protective forest tasks and nature conservation functions as well as to the establishment of "climate-smart" mountain forests in Austria. The Austrian forest ownership communities and larger forest enterprises with regular sample inventory and forest management benefit from digital inventory solutions with person-carried laser scanners (PLS) as well as the area-accurate stock and assortment and productivity forecasts achieved by combining PLS data with remote sensing data. Low-threshold access to an easy-to-use and digital inventory and planning tool will create incentives for regular and sustainable forest management in Austria's small private forests.

The forest inventory provides information and data as a basis for decision-making in forest planning with regard to the implementation of operational interventions and the achievement of economic objectives. In addition to traditional surveying methods, forest inventories with laser scanners have recently become increasingly important. While terrestrial laser scanners (TLS) have been in use for some time, the first experiences and research results on forest inventories with mobile person-carried laser scanners (PLS) have recently become available. In the last six years, automatic algorithms for the evaluation of 3D laser data have been developed at the BOKU Institute of Forest Growth, thus laying the foundation for a modern sensor-based forest inventory. The measurement process with PLS takes about 10 min for a sample circle with 20 m radius. In a series of publications, a large number of reference measurements have shown that tree cover rates of over 97% can be achieved. The mean deviation (bias) of the BHD measurement is 0 - 0.7 cm, with an average error (RMSE) of 1.5 to 3 cm. Tree heights can be automatically determined with a mean deviation of0 to 0.2 m and an average error of 1.5 to 2.1 m. With the portable laser scanner, precise measurement values can now be determined in three-dimensional space in a short time, and the new laser-based forest inventory procedure is thus on the verge of general practical applicability. Together with the Austrian Federal Forests, the new laser-based digital forest inventory procedure is now to be tested in practice on around 300 sample areas in the Ebensee forest district, both in the productive forest and in the protection forest of the Rindbach catchment area. Furthermore, the automatic evaluation routines are to be further developed. In addition to the traditional inventory parameters, the laser scans will be used to automatically and precisely derive indicators of regeneration density, crown closure for the establishment of fir regeneration, and deadwood stocks.