Jukka Malinen

Airborne laser scanning-based decision support for wood procurement planning

We present a decision support tool for guiding the selection of marked stands based on airborne laser scanning (ALS) data. We describe three stages, namely (1) wall-to-wall mapping of the stands matured for cutting using low-density ALS data; (2) tree-level inventory of these stands using high-density ALS data and (3) theoretical bucking of the imputed tree stems to produce detailed information on their characteristics. We tested them in a Scots pine dominated boreal forest area in Eastern Finland, where 79 sample plots were measured in the field. The detection of the stands matured for cutting had a success rate of 95% and our results demonstrated a further potential to limit the result towards stands dominated by certain species by means of intensity values derived from the low-density ALS data. The applied single-tree detection and estimation chain produced detailed tree-level information and realistic diameter distributions, yet the detection was highly emphasised on the dominant tree layer. The error levels in the estimates were generally less than standard deviations of the field attributes. Finally, plot-level accumulations of saw-log volumes were found rather similar, whether the input was based on the imputed tree data or trees measured in the field. The results are considered useful for ranking the stands based on their properties, whether the aim in the wood procurement is to focus on certain species or to select stands suitable for production needs.

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.

A comparative study of the use of laser scanner data and field measurements in the prediction of crown height in boreal forests

Abstract This study compares the results of the prediction of crown height characteristics using airborne laser scanner (ALS) data and intensive field measurements in boreal forests. The data consisted of 31 sample plots located in Kalkkinen, southern Finland. Crown height models were constructed at both the tree and plot level. Scots pine, Norway spruce and birches were used. The models included independent variables of tree levels, such as tree height, crown area and independent plot-level variables, i.e. canopy height and density quantiles and proportion of vegetation hits. Field measurement-based models used tree height and diameter at breast height as the independent tree-level variables, whereas basal area, mean diameter and height were used as the plot-level variables. The results indicated that the ALS-based crown height models were more accurate than the field measurement-based models when plot-level information was used as independent variables. However, the field measurement-based tree-level models for Scots pine and Norway spruce were more accurate than the ALS-based models. Even so, the accuracy of the different models was very similar and the study data set was quite small. The results of this study can be used for different tree growth studies and for the assessment of tree stock quality in boreal forests.

Metrics for Distribution Similarity Applied to the Bucking to Demand Procedure

Abstract In the computerized bucking to demand procedure bucking is done according to a given price list and demand matrix, which defines the demands for different log length-diameter class proportions. To achieve as good a log length-diameter distribution as possible, the computer compares demand and actual output to appropriately direct bucking. A comparison has been made with a variable called distribution level, which, however, is unable to distinguish between error that is close to the optimum log length-diameter class proportion and error that is further away. In addition, the distribution level does not distinguish between log length-diameter classes, even though error in one class can be far more undesirable than in another. In this study, bucking to demand using the distribution level was compared to bucking to value and bucking to demand using the penalty segmented distribution level, squared distribution level, chi-square formula and flexible penalty segmented distribution level. The bucking outcome employing these various techniques was achieved by using a bucking simulator and artificially generated stand and stem data. The results show that the best bucking outcomes were produced by methods with a squared error term, i.e. the squared distribution level, chi-squared formula and flexible penalty segmented distribution level. In addition, it was possible to direct error toward preferred log length-diameter classes without substantial loss in overall goodness of fit.

Modeling Backhauling on Finnish Energy-Wood Network Using Minimizing of Empty Routes

Abstract This study introduces a support method to use in modeling backhauling. The method minimizes a truck’s on-road driving while empty. The backhauling model is based on a commonly used timber transport allocation model. Here, this model is applied to a simulated energy- wood network. The resulting optimization provides two different delivery plans for two-way transportation: one with a constraint to minimize travel distances when empty and the other without this constraint. By applying the empty-route minimization method, the best return routes for trucks are determined beforehand with fewer alternatives then left to be solved by the backhauling model. The results prove that the method can be used to minimize empty-route driving, but further development of the empty-route minimization method is still needed before it can be used in combination with the optimization of backhauling. Therefore, the effects of empty-route minimization on the transportation distances with respect to stand and hauling alternatives are discussed. In addition, the possibility of increasing the profitability of transportation, through the use of the method to optimize energy-wood backhauling, is also discussed.

Variation in age, annual usage and resale price of cut-to-length machinery in different regions of Europe

ABSTRACT The high price of cut-to-length machines requires careful planning of investment in new or second-hand machines. The investment is influenced by machine usage, and is also affected by maintenance, insurance and repair costs, harvesting conditions, number of machine relocations, and availability of working opportunities and employment. In this study, age, size, annual usage and price of the cut-to-length harvesters and forwarders for sale in Europe was investigated, using sales data from the online marketplace. The average age of harvesters was 7.3 years and the average age of forwarders was 7.5 years. The newest machines were on offer in the Northern countries (6.5 and 6.1 years for harvesters and forwarders, respectively). The oldest harvesters were on offer in Western Europe (8.1 years) and Eastern Europe (8.2 years) and the oldest forwarders in Eastern Europe (9.9 years). The average annual use of both harvesters and forwarders were notably high in the Baltic and Northern countries compared to the Western and Eastern Europe. On average, the annual use was 1759 and 1913 h year−1 for the harvesters and forwarders, respectively. The average resale price of harvesters was more dependent on age than total use. For forwarders, both age and total usage had a similar explanatory value. For newer CTL machines, aged between 1 and 5 years, the bigger size class of the machine corresponded to higher price. Older machines did not exhibit such correspondence, whereas the annual usage showed high correspondence on the resale value of the machine.

Alternative operation models for using a feed-in terminal as a part of the forest chip supply system for a CHP plant

The fuel supply of forest chips has to adapt to the annual fluctuations of power and heat generation. This creates inefficiency and unbalances the capacity utilization of the fuel supply fleet in the direct fuel supplies from roadside storages to power and heat generation. Terminals can offer an alternative approach for the fleet management of fuel supplies in terms of smoothing the unbalanced fleet use towards more even year‐round operations. The aim of the study was to compare the supply costs of a conventional direct forest chip supply to an alternative fuel supply with the use of a feed‐in terminal using the discrete‐event simulation method. The influences of the terminal location, terminal investment cost, outbound terminal transport method, terminal truck utilization and quality changes of terminal‐stored forest chips for the fuel supply cost were studied in the case environment. By introducing a feed‐in terminal and a shuttle truck for the transports of terminal‐stored forest chips, the total supply cost was 1.4% higher than the direct fuel supply scenario. In terminal scenarios, the supply costs increased 1–2% if the cost of the terminal investment increased 30%, the distance to the terminal increased from 5 to 30 km or the total annual use of a terminal truck decreased 1500 h. Moreover, a 1 per cent point per month increase in the dry matter loss of terminal‐stored chips increased the total supply cost 1%. The study revealed that with the relatively low additional cost, the feed‐in terminal can be introduced to the conventional forest chip supply. Cost compensation can be gained through the higher annual use of a fuel supply fleet and more secured fuel supply to power plants by decreasing the need for supplement fuel, which can be more expensive at a time of the highest fuel demand.

Description and evaluation of Prehas software for pre-harvest assessment of timber assortments

Prehas is a decision support tool for assessing the amount and value of harvestable timber, including predictions of timber assortment recovery, length-diameter distribution of logs, and value recovery. Predictions are based on previously collected cut-to-length harvester stem data (stm-data), which is stored by the software as a stem database, and a non-parametric k-MSN method. Using easily achievable search variables, Prehas produces stem group estimates, including stem diameters at 10 cm intervals for each stem. This stem group can be bucked using a bucking simulator (included in Prehas) to achieve the estimates of timber assortment recovery, value, and log length-diameter distribution. Prehas has three versions: Prehas-International, Prehas-Scotland, and Prehas-Finland, of which the latter is also capable of predicting the technical quality of stems to be used in bucking simulations. The software includes routines for the user to collect and save their own stm-data representing local forests. This article describes the structure and methodology of Prehas. To assess the performance of Prehas, a test was conducted using the empirical data collected for measurements of dimensions and quality of trees from sample plots. The data consisted of 61 stands located in south-eastern Finland including commercial clear-cutting stands in private and state forests. Prehas’s predictions were slightly more reliable than those of the compared timber assortment recovery regression models for southern Finland.

Collaborative Railway Transportation Strategy to Increasing Imports of Russian Wood for the Finnish Forest Energy Industry

In this research, the logistics alternatives of Finnish forest industry under increasing imports of Russian wood are discussed. The paper show that the transportation strategy of a third party logistic provider (3PLs) used in the railway has large implications for the logistics of imported wood from Russia. In the primary data used in this research, the basic scenario described the railway transportation strategy of 3PLs at 2011, before Russia’s World Trade Organization (WTO) membership. The alternative scenarios described the strategies of 3PLs for changed wood transportation and storing needs of imported Russian wood under WTO. In the alternative scenarios also the railway wagon rotation was adjusted to reach the global optimum strategy for more efficient logistics of plants. After adjusting merely 3PLs’ wagon traffic flow, the global optimum was not reached, since the reduction of empty wagons caused severe shortages of wood flow and later a need to cut down storage inventory at districts and plants increasing total logistics costs. As the conclusion, the model based on the dynamic multiple objective linear programming (DMOLP) is recommended to the supply chain parties, as the adaptation of Russian wood import to the global railway transportation environment would require collaborative logistics and integrated optimizations of wood and the wagon-traffic flows to be carried out.