Jori Uusitalo

Considering virtual worlds as representations of landscape realities and as tools for landscape planning

The development of computer tools for creating and representing virtual worlds has dramatically increased our abilities to capture salient aspects of the environment and communicate them to audiences remote from the landscape under study. The speed and quality of generation of visual imagery, as well as the editing power computers offer, has already dramatically extended the capabilities of practitioners and researchers in representing scenic views. The immersion, motion, and sound offered by virtual worlds may greatly extend the ecological validity of environmental representations and allow for deeper and more meaningful study of the effects of the real world on human experience. However, while the tools are being widely and increasingly adopted, there has been little discussion of the nature of the advantages being gained, nor the cautions that may be necessary. This paper examines the suitability of Virtual Reality (VR) technology for supporting environmental decision-making. We discuss and categorize different aspects of human-computer interfaces and then discuss to what extent the attributes of VR correspond to the needs of landscape representation.

Characteristics and Significance of a Harvester Operators’ Working Technique in Thinnings

Abstract Productivity levels between harvester operators have been noted to vary significantly, by up to 40% in similar stands. It is believed that differences originate from the operators cutting techniques, motoric skills, planning of work, experience, felling order of removable trees, decision processes at the working location, machine properties and the surrounding environment. The objective of this study is to examine and compare six harvester operators and to detect those features of working technique that improve and rationalise the work. Consequently, improving the basic working technique can raise average productivity. The harvester operators’ work was examined by using the normal stopwatch study method and the operators’ working technique was registered for each handled tree. Working technique observations were adjoined to stopwatch the study time units as a large matrix after data collection. Results indicate that unnecessary stem movements in the felling phase should be avoided. The stem should be processed close to the stump so that the positioning-to- cut distance to next removable tree is short. This reduced positioning-to-cut time for the next felling. In processing, a productive operator can operate without big delays and the variations in processing times for same stem sizes are small. Furthermore, the productive operator avoids reversing when he is doing normal harvesting work.

A Framework for CTL Method-Based Wood Procurement Logistics

Abstract Wood procurement logistics has developed dramatically during the last few decades. The adaptation of general logistics theory, increasing customer orientation, product-based bucking, the externalization of work processes, the expansion of international wood trade and the rapid development of management tools and methods have changed the characteristics of wood procurement tremendously. Consequently, there is a growing need to redefine the concept of wood procurement. This paper attempts to lay down a general framework for CTL (cut-to-length) method-based wood procurement management and to highlight the most important research and development objectives in this area. In wood procurement the main customer service goals are price, dimensional requirements, quality requirements and the ability to react to changes. The price is always important, but the smaller the proportion the wood cost is of the total production costs, the less significant the price becomes. The importance of quality and dimensional requirements increases with the rising value of wood. Due to improved inventory booking systems and transportation optimization systems, wood procurement companies have managed to decrease stock levels, thus decreasing rate costs. The company may aim to decrease the level of stock, but not without possible additional costs. According to logistics theories, an increase in stock levels increases storage costs but, on the other hand, a decrease of stock levels increases transportation costs and the risk of lost profit. Seasonal variation and the ability to react to changes have great significance to logistics costs in wood procurement. Small stumpage reserves inevitably lead to expensive harvesting and transportation activities. But more research should, in the future, also be directed at improving classifications of harvesting and transportation accessibility. In the Nordic countries significant progress both in tree bucking control and transportation allocation has been achieved in practice, but they are still considered as separate processes. It is in most cases undesirable to cut many products from the same stand, since it implies too many loading and transportation operations. Therefore, it is necessary to choose which products in what quantities may be cut from each stand. This means that tree bucking control and wood transportation problems should not be considered as separate tasks, but instead be optimized as a whole. If they are considered as separate processes the gains achieved through better product characteristics are lost in increasing transportation costs. Current wood pricing systems make it difficult to fully exploit the advantage that could be gained through this kind of optimization.

Virtual Forest Management: Possibilities and Challenges

Abstract Scientists and managers are increasingly turning to computer modeling and visualization tools to enable them to evaluate the effects of harvest practices better, depict various characteristics and variation existing in the forest, and communicate the impact of environmental changes. This paper examines the suitability of virtual reality (VR) technology in supporting forest managers or forest owners in their decisions. VR is particularly useful for helping to deal with the following issues in forest management planning: time dependence, irreversibility of decisions, spatial-quantitative variation of features and multiple objectives. It helps managers and stakeholders understand the relationship between underlying data and landscape planning. Some of the key challenges faced in making VR work are: insufficient resolution in forest inventory data, need to re-delineate stands to allow for multiple use planning, adjusting realism of features in the images and linking data currently held by a variety of disparate agencies and owners. Existing mean-based inventories will, for the short to medium term, limit the extent to which VR technologies are used in actual forest management planning.

An Activity-Based Costing Method for Sawmilling

The production cost of lumber is a key factor when determining the price of logs at a sawmill gate. Some of the production costs are also manageable elements in price setting. There is a lack of ex...

Predicting knottiness of Pinus sylvestris for use in tree bucking procedures

Abstract The quality and accompanying value of Scots pine (Pinus sylvestris L.) lumber varies markedly in the Nordic countries. Consequently, tree bucking has a great impact on the economic result. The objectives of this study were (1) to analyse which knot characteristics usually reduce pine lumber sawn from the butt-logs to the next quality grade, (2) to determine the most appropriate characteristics that could be used in predicting lumber quality, and (3) to develop models that could be used in practice for predicting the probability of certain quality grades. The study was based on field experiments and test sawing data on 100 Scots pine stems from south-western Finland. Since the results showed that the maximum dead knot is the most crucial knot characteristic when the first cross-cutting point is determined, models were created that predict the height of the first dead knot that lowers grade A to B (B-grade dead knot). Both early growth rate and dead branch height should be measured to predict pine butt-log quality. Early growth rate seems to be appropriate in predicting between-stand variation, while dead branch height is appropriate for predicting within-stand variation.

Variation of the factors affecting soil bearing capacity of ditched pine bogs in Southern Finland

Recent studies indicate that the most important characteristics affecting the bearing capacity of pine bogs are tree volume and the strength and moisture content of the uppermost layers of moss. From a forest operations point of view it would, therefore, be essential to understand to what extent these properties vary and what the possibilities are to predict these properties prior to operations. The aim of this study was to investigate spatial variation of a basal area, soil strength and moisture content, as well as their co-variation, of ditched pine bogs in Southern Finland. The basal area is at its highest close to the ditch and to certain extent decreases with increasing distance from the ditch. The mass of living roots logically had significant correlation with the shear strength. The relationship between the shear strength and the mass of living roots confirms the applicability of spiked shear vane as a reliable tool in assessing the bearing capacity of peat soil. Both the closest trees and distance to the nearest ditch are significant predictors of volumetric water content in the topmost peat layers.

Comparison of terrestrial laser scanning and X-ray scanning in measuring Scots pine (Pinus sylvestris L.) branch structure

ABSTRACT While X-ray scanning is increasingly used to measure the interior quality of logs, terrestrial laser scanning (TLS) could be used to collect information on external tree characteristics. As branches are one key indicator of wood quality, we compared TLS and X-ray scanning data in deriving whorl locations and each whorl’s maximum branch and knot diameters for 162 Scots pine (Pinus sylvestris L.) log sections. The mean number of identified whorls per tree was 37.25 and 22.93 using X-ray and TLS data, respectively. The lowest TLS-derived whorl in each sample tree was an average 5.56 m higher than that of the X-ray data. Whorl-to-whorl mean distances and the means of the maximum branch and knot diameters in a whorl measured for each sample tree using TLS and X-ray data had mean differences of −0.12 m and −6.5 mm, respectively. One of the most utilized wood quality indicators, tree-specific maximum knot diameter measured by X-ray, had no statistically significant difference to the tree-specific maximum branch diameter measured from the TLS point cloud. It appears challenging to directly derive comparative branch structure information using TLS and X-ray. However, some features that are extractable from TLS point clouds are potential wood quality indicators.

Predicting probability of A-quality lumber of Scots pine (Pinus sylvestris L.) prior to or concurrently with logging operation

ABSTRACT Knot properties have a profound influence on the suitability of wood for many wood products leading to significant value differences between different quality grades. It would therefore be rather advantageous to maximise the volume of good quality timber attained from the logs. The objective of this study was to assess how well A-quality lumber of Scots pine derived from log tomography features can be predicted with characteristics measured prior to or concurrently with the logging operation. The study is based on field experiments and X-ray scanning of 204 stems from southern Finland in 2014. We employed mixed logistic regression techniques to model the relationship between the main stem characteristics and probability of A-quality lumber. From the tree characteristics that can be measured or detected from standing trees, the height from the ground level to the lowest dead branch was found to be the best predictor of A-quality lumber. From the characteristics that could, at least in theory, be detected and measured at the moment of harvest, early growth rate and size of tree were found to be the best combination for predicting the probability of A-class quality.

Wheel rut measurements by forest machine-mounted LiDAR sensors – accuracy and potential for operational applications?

ABSTRACT Soil rutting caused by forest operations has negative economic and ecological effects and thus limits for rutting are set by forest laws and sustainability criteria. Extensive data on rut depths are necessary for post-harvest quality control and development of models that link environmental conditions to rut formation. This study explored the use of a Light Detection and Ranging (LiDAR) sensor mounted on a forest harvester and forwarder to measure rut depths in real harvesting conditions in Southern Finland. LiDAR-derived rut depths were compared to manually measured rut depths. The results showed that at 10–20 m spatial resolution, the LiDAR method can provide unbiased estimates of rut depth with root mean square error (RMSE) < 3.5 cm compared to the manual rut depth measurements. The results suggest that a LiDAR sensor mounted on a forest vehicle can in future provide a viable method for the large-scale collection of rut depth data as part of normal forestry operations.