Pertti Harstela

Application of Most Similar Neighbor Inference for Estimating Marked Stand Characteristics Using Harvester and Inventory Generated Stem Databases

Abstract The purpose of this study was to develop and test the application of non-parametric Most Similar Neighbor Inference (MSN) for wood procurement planning. An application developed using this method would be a part of a stem database in Finnish forest enterprises and could predict characteristics of a marked stand with accuracy demanded by bucking simulation. A stem database includes representative samples of stands and stems, applications to control and update data and applications to utilize the database. The study materials used consist of two different kinds of data: data collected by harvesters and historical forest inventory data. The harvester collected stem data came from stands in central Finland, whereas forest inventory data was obtained from all over Finland. The accuracy of the MSN method was analyzed by estimating characteristics of tree stocks and by comparing simulated spruce, pine and birch log length-diameter distributions with the information from actual stands. The application presented was found to be a useful and flexible tool for predicting characteristics of marked stands based on the stem data collected by a harvester. The forest inventory data was found less suitable for reference data. The most efficient way to create a length-diameter distribution was to calculate length-diameter class estimates from reference stands as weighted averages of the corresponding length-diameter class. The proposed method appears robust against measurement errors of search variables.

Estimating the Characteristics of a Marked Stand Using k-Nearest- Neighbour Regression

The purpose of this study was to develop the k-nearest-neighbour method as a wood procurement planning tool. Traditionally, sampling measurement of standing trees has been used to obtain advance information on marked stands. In this study, key figures such as sawtimber/pulpwood ratio in pine and spruce stands, diameter and height distribution in spruce stands, diameter and quality distribution in pine stands, and quality distribution by diameter classes in pine stands were estimated using k-nearest-neighbour regression. The material consisted of 716 stands. Stands were located in the eastern Finland. Information regarding every stand was collected from the information system of one large Finnish timber-procurement organization. The accuracy of the k-nearest-neighbour method was compared with the traditional planning inventory method and stand inventory method. The created model was found to be a useful tool in the planning of wood procurement.

Effect of Seedling Production and Long-Distance Transportation Planning Strategies on Transportation Costs of a Nursery Company

Abstract In Finland, the number of nurseries has been decreasing year by year, and it seems probable that in the near future this trend will continue. It can be assumed that greater economies of scale could also be achieved in Finnish seedling production by enlarging the size of production units [9, 10]. The management strategies used by a nursery company for long-distance seedling transportation were compared with different allocations of seedling production among nurseries. To determine the optimal transportation costs in different strategies for seedling production and planning of long-distance transportation, linear programming (LP) was applied. To manage spatial information, a geographical information system (GIS) was used. The current development towards seedling transportation managed by nursery companies seems to have marked advantages in the cost-effectiveness of transportation. The relative improvement in cost-effectiveness caused by centralized transportation strategy (CTS) compared to decentralized transportation strategy (DTS), which is the mostly used strategy in seedling transportation planning in Finland, varied from 13.0% to 36.5%, depending on the number of nurseries and the degree of specialization of production among them. These results will be useful for nursery companies and forest owners’ associations (FOAs) when they evaluate the cost effects of production allocation, product specialization and systems of transportation management.

Bracke- ja M-Planter-istutuslaitteiden teknis-taloudellinen vertailu

Seloste artikkelista: Rantala, J., Harstela, P., Saarinen, V.-M. & Tervo, L. 2009. A techno-economic evaluation of Bracke and M-planter tree planting devices. Silva Fennica 43 (4) : 659– 667.