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Silva Fennica vol. 42 no. 1 | 2008

Category : Research article

article id 267, category Research article

Manfred Gronalt, Peter Rauch. (2008). Vendor managed inventory in wood processing industries – a case study. Silva Fennica vol. 42 no. 1 article id 267. https://doi.org/10.14214/sf.267

Keywords: building materials; service level; solid structure timber; SST; wood construction

Abstract | View details | Full text in PDF | Author Info

Solid structure timber (SST) is an important building material in the wood construction business, in which its production volume is largely related to that respective business. Due to the large variability in the demand and seasonal factors, SST producers’ inventories are likely to be simultaneously overstocked for one type of timber and out of stock of another. An inventory policy that ensures a high service level and relatively low stocks is required. In the present paper, we propose the vendor managed inventory (VMI) approach for controlling the stock of deals that are produced at a sawmill and delivered as raw material for SST-production. We evaluate two VMI implementations against the actual inventory management for three different market scenarios. Furthermore, we layout the necessities for reconfiguring the business processes, and subsequently set up an organisational framework within VMI, which is indeed applicable in this segment of the woodworking industry. In our application background, VMI as an inventory control system is able to reduce the overall raw material stock by more than 37% by simultaneously increasing the SST service level.

Gronalt, BOKU – University of Natural Resources and Applied Life Sciences, Feistmantelstr. 4, 1180 Vienna, Austria E-mail: mg@nn.at
Rauch, BOKU – University of Natural Resources and Applied Life Sciences, Feistmantelstr. 4, 1180 Vienna, Austria E-mail: peter.rauch@boku.ac.at

article id 266, category Research article

Mikko Havimo, Juha Rikala, Jari Sirviö, Marketta Sipi. (2008). Distributions of tracheid cross-sectional dimensions in different parts of Norway spruce stems. Silva Fennica vol. 42 no. 1 article id 266. https://doi.org/10.14214/sf.266

Keywords: Norway spruce; cell wall thickness; earlywood; latewood; tracheid dimension; tangential width; radial width

Abstract | View details | Full text in PDF | Author Info

Distributions of three cross-sectional dimensions: radial and tangential tracheid width, and cell wall thickness in different timber assortments of Norway spruce were investigated. Wood samples from a mature stand were measured with SilviScan. In the analysis, virtual trees were constructed from measurement data, and divided into three assortments: whole stem, top pulpwood and sawmill chips. Average values and distributions of the properties were calculated for all assortments, and distributions divided into earlywood and latewood across the whole tree assortment. There was considerable variation within latewood in all three cross-sectional dimensions, but variation in earlywood was slight in radial width and cell wall thickness. In earlywood, tangential tracheid width showed considerable internal variation, and the difference between earlywood and latewood in tangential width was small. Within-assortment variation of all three properties was larger than between assortments. We may conclude that only a moderate difference in pulp properties can be achieved by sorting raw material into sawmill chips and top pulpwood. Pulp fractionation into earlywood and latewood seems to be a more efficient method, since it gives classes with small within-class variation and distinct average properties. However, it should be kept in mind that the results are valid only in mature stands, where growth rate variation and juvenile wood content are small.

Havimo, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: mikko.havimo@helsinki.fi
Rikala, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: jr@nn.fi
Sirviö, KCL, P.O. Box 70, FI-02151 Espoo, Finland E-mail: js@nn.fi
Sipi, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ms@nn.fi

article id 265, category Research article

Emil Cienciala, Erkki Tomppo, Arnor Snorrason, Mark Broadmeadow, Antoine Colin, Karsten Dunger, Zuzana Exnerova, Bruno Lasserre, Hans Petersson, Tibor Priwitzer, Gerardo Sanchez, Göran Ståhl. (2008). Preparing emission reporting from forests: use of National Forest Inventories in European countries. Silva Fennica vol. 42 no. 1 article id 265. https://doi.org/10.14214/sf.265

Keywords: forest carbon pools; greenhouse gas inventory; Kyoto Protocol; UNFCCC

Abstract | View details | Full text in PDF | Author Info

We examine the current status of greenhouse gas inventories of the sector Land Use, Land-Use Change and Forestry (LULUCF), in European countries, with specific focus on the utilization of National Forest Inventory (NFI) programs. LULUCF inventory is an integral part of the reporting obligations under the United Nations Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol. The analysis is based on two questionnaires prepared by the COST Action E43 “Harmonisation of National Forest Inventories in Europe”, which were answered by greenhouse gas reporting experts in European countries. The following major conclusions can be drawn from the analysis: 1) definitions used to obtain carbon pool change estimates vary widely among countries and are not directly comparable 2) NFIs play a key role for LULUCF greenhouse gas estimation and reporting under UNFCCC, and provide the fundamental data needed for the estimation of carbon stock changes covering not only living biomass, but increasingly also deadwood, litter and soil compartments. The study highlights the effects of adopting different definitions for two major reporting processes, namely UNFCCC and FAO, and exemplifies the effect of different tree diameter thresholds on carbon stock change estimates for Finland. The results demonstrate that more effort is needed to harmonize forest inventory estimates for the purpose of making the estimates of forest carbon pool changes comparable. This effort should lead to a better utilization of the data from the European NFI programs and improve the European greenhouse gas reporting.

Cienciala, Institute of Forest Ecosystem Research (IFER), Areal 1. Jilovske a.s. 1544, 254 01 Jilove u Prahy, Czech Republic E-mail: emil.cienciala@ifer.cz
Tomppo, Metla, Finnish Forest Research Institute, Finland E-mail: et@nn.fi
Snorrason, Icelandic Forest Research, Iceland E-mail: as@nn.is
Broadmeadow, Forestry Commission, Forest Research Alice Holt Logdge, United Kingdom E-mail: mb@nn.uk
Colin, French National Forest Inventory, France E-mail: ac@nn.fr
Dunger, Federal Research Centre for Forestry and Forest Products, Institute of Forest Ecology and Forest Assessment, Germany E-mail: kd@nn.de
Exnerova, Institute of Forest Ecosystem Research, Czech Republic E-mail: ze@nn.cz
Lasserre, Department of Environment and Territory Sciences and Technologies, University of Molise, Italy E-mail: bl@nn.it
Petersson, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Sweden E-mail: hp@nn.se
Priwitzer, National Forest Centre, Forest Research Institute. Slovak Republic E-mail: tb@nn.sk
Sanchez, Forest Health Unit, General Directorate for Biodiversity, Environmental Ministry, Spain E-mail: gs@nn.es
Ståhl, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Sweden E-mail: gs@nn.se

article id 264, category Research article

Yrjö Nuutinen, Kari Väätäinen, Jaakko Heinonen, Antti Asikainen, Dominik Röser. (2008). The accuracy of manually recorded time study data for harvester operation shown via simulator screen. Silva Fennica vol. 42 no. 1 article id 264. https://doi.org/10.14214/sf.264

Keywords: accuracy of timing; mixed effects models; time studies

Abstract | View details | Full text in PDF | Author Info

The aim of the study was to investigate the effect of work experience on the accuracy and variation of observers recording the operation time of a harvester. A simulated thinning operation using a harvester, shown as video via a television screen in laboratory conditions, was observed by 20 inexperienced students and 10 experienced work study researchers. All the observers timed the different work elements of the harvester work with special fieldwork timers. The duration of different work elements measured by the human observers were compared to the corresponding recordings by the harvester’s automated data collector. Although the inexperienced students made more measurement mistakes than the experienced researchers, the differences in measurement error averages were not statistically significant between the groups. However, the variances of tree specific errors were significantly higher in the measurements done by the students. As inexperienced recorders, the students were not able to properly record short work elements, which lasted a maximum of 4 seconds. Due to systematic measurement errors, there was a large variation in the timing structures of the work elements among all observers. Observers’ skills and experience seems to affect measurement accuracy and thus the derived results, especially in intensive time studies. Therefore, the recorder should receive detailed training and practical experience in timing of different work elements of forest operations. In the future, with the use of automated data collectors time studies with large, detailed and accurate data will be implemented. However, due to the varying timing conditions in the forest, manual data collection is still required because of its greater flexibility.

Nuutinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: yrjo.nuutinen@metla.fi
Väätäinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kv@nn.fi
Heinonen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jh@nn.fi
Asikainen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: aa@nn.fi
Röser, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: dr@nn.fi

article id 263, category Research article

Aksel Granhus, Dag Fjeld. (2008). Time consumption of planting after partial harvests. Silva Fennica vol. 42 no. 1 article id 263. https://doi.org/10.14214/sf.263

Keywords: planting; work study; mechanical site preparation; partial cutting; scarification

Abstract | View details | Full text in PDF | Author Info

Partial harvesting combined with underplanting may be a means to reduce the risk of regeneration failure when e.g. unfavourable microclimatic conditions or severe damage by bark-feeding insects may be expected after clear-cutting, and to maintain or establish certain stand structures or tree species mixture. In this study, we performed time studies of manual planting with and without prior site preparation (patch scarification, inverting) in partially harvested stands of Norway spruce (Picea abies (L.) Karst.). The harvest treatments included basal area removals of approx. 35, 45, and 55%, and a patch clear-cut treatment that was assumed to provide the same conditions for planting as conventional clear-cutting. Site preparation had a much larger influence on time consumption plant^–1 (main time) than the harvest treatment. The lowest time consumption was found with inverting and the highest without site preparation. The time spent on walking between planting spots increased with decreasing harvest intensity, reflecting a lower density of planted seedlings in the partially harvested stands. A corresponding increase in main time per plant only occurred after site preparation, since the time spent on clearing the planting spot (removal of logging residue and humus) on untreated plots was higher at the higher harvest strengths. The variation in time consumption attributed to the six replicate stands was large and mainly due to the difference among stands planted by different workers.

Granhus, Norwegian University of Life Sciences, Dept. of Ecology and Natural Resource Management (INA), P.O.Box 5003, NO-1432 Ås, Norway E-mail: aksel.granhus@umb.no
Fjeld, Swedish University of Agricultural Sciences, Dept. of Forest Resource Management, SE-901 83 Umeå, Sweden E-mail: df@nn.se

article id 262, category Research article

Julian C. Fox, Huiquan Bi, Peter K. Ades. (2008). Modelling spatial dependence in an irregular natural forest. Silva Fennica vol. 42 no. 1 article id 262. https://doi.org/10.14214/sf.262

Keywords: correlogram; Eucalypt; growth modelling; moving average autoregression; Moran’s I; spatial autocorrelation

Abstract | View details | Full text in PDF | Author Info

The spatial dependence present in a natural stand of Eucalyptus pilularis (Smith) dominated mixed species forest was characterised and modelled. Two wildfires imposed a significant spatial dependence on the post disturbance stand. It was hypothesised that spatial variation in the intensity of the wildfires generated the observed structures. The influence of patch formation, micro-site variability and competitive influences were also noted in the residuals of a distance-dependent individual-tree growth model. A methodology capable of modelling these complicated patterns of observed dependence was sought, and candidates included the spatial interaction, direct specification and Papadakis methods. The spatial interaction method with a moving average autoregression was identified as the most appropriate method for explicitly modelling spatial dependence. Both the direct specification and Papadakis methods failed to capture the influence of competition. This study highlights the possibility that stand disturbances such as natural and artificial fires, insect and fungal attacks, and wind and snow damage are capable of imposing powerful spatial dependencies on the post disturbance stand. These dependencies need to be considered if individual tree growth models are to provide valid predictions in disturbed stands.

Fox, School of Forest and Ecosystem Science, University of Melbourne, Burnley Campus, 500 Yarra Blvd, Richmond, Victoria 3121 Australia E-mail: jcfox@unimelb.edu.au
Bi, Forest Resources Research, New South Wales Department of Primary Industries, PO Box 100, Beecroft, NSW 2119 Australia E-mail: hb@nn.au
Ades, School of Forest and Ecosystem Science, University of Melbourne, Burnley Campus, 500 Yarra Blvd, Richmond, Victoria 3121 Australia E-mail: pka@nn.au

article id 261, category Research article

Miina Rautiainen, Matti Mõttus, Pauline Stenberg, Sanna Ervasti. (2008). Crown envelope shape measurements and models. Silva Fennica vol. 42 no. 1 article id 261. https://doi.org/10.14214/sf.261

Keywords: Norway spruce; Scots pine; crown profile; reflectance model; remote sensing

Abstract | View details | Full text in PDF | Author Info

This paper addresses tree crown envelope shape modeling from the perspective of optical passive remote sensing. The aims are 1) to review the specific requirements of crown shape models and ground measurement techniques in optical remote sensing, and 2) to present preliminary results from empirical, parametric crown shape and volume modeling of Scots pine and Norway spruce applicable in Finland. Results indicated that the basic dimensions (maximum radius, its height and crown length) of tree crowns were better predicted for pines, but the profile shape of the upper part of the crowns varied more than in spruce. Pine crowns were also slightly less concave than spruce crowns. No regularities were observed concerning the lower part of the crowns. The asymmetry of crowns increased as a function of tree age for both species, spruce crowns being more asymmetric than pine crowns. A comparison of measured crown volume with several simple geometrical crown shape envelopes showed that using a cone as a crown shape model for Scots pine and Norway spruce underestimates crown volume most severely. Other crown envelope shape models (e.g. ellipsoids) rendered crown volumes closer to the measured volume and did not differ considerably from each other.

Rautiainen, Tartu Observatory, 61602 Tõravere, Estonia, and Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: miina.rautiainen@helsinki.fi
Mõttus, Tartu Observatory, 61602 Tõravere, Estonia E-mail: mm@nn.ee
Stenberg, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ps@nn.fi
Ervasti, City of Vantaa, Land Use and Environment / Green Area Unit, Kielotie 13, FI-01300 Vantaa, Finland E-mail: se@nn.fi

article id 260, category Research article

Panagiotis Michopoulos, George Baloutsos, Anastassios Economou. (2008). Nitrogen cycling in a mature mountainous beech forest. Silva Fennica vol. 42 no. 1 article id 260. https://doi.org/10.14214/sf.260

Keywords: bulk deposition; Fagus sylvatica; litterfall; stemflow; stream water; throughfall

Abstract | View details | Full text in PDF | Author Info

The nitrogen cycle in a mature, mountainous European beech (Fagus sylvatica) forest in Greece was examined for two hydrological years, 2001–2002 and 2002–2003. Bulk deposition was 1383 mm in 2001–2002 and 2392 mm in 2002–2003. Winter temperatures were mild in the first year and low in the second year. Despite these climatological differences, the inorganic N inputs to the forest floor, by means of throughfall and stemflow, were quite similar for the two years, i.e. 12.4 and 14.6 kg ha^–1 yr^–1. Litterfall production was significantly (p < 0.05) higher in the second year but the N amounts in litterfall did not differ. The ratio of N/P in foliar tissue did not change significantly in 2003 compared with ratio values in the last years. The N amounts used for the annual stem and branch increments are rather high preventing, in this way, some nitrogen from being recycled in the near future. The total soil N content to a depth of 80 cm amounted to more than 5000 kg ha^–1, and the C/N ratio in the Oh horizon was approximately 15 but the beech forest did not appear susceptible to N leaching. The concentrations of ammonium and nitrate N in stream water did not reach high values reported in the literature, and did not differ significantly in the two hydrological years. The fluxes of inorganic N in throughfall plus stemflow were higher than those in stream water indicating N retention in soil. Another reason for N retention in the ecosystem is probably the large difference between N requirements and uptake indicating N deficiency. Despite the maturity of the beech trees, the low C/N ratio in the Oh horizon and the relatively high N content in soil, the forest can be considered to be neither saturated nor having reached a N saturation transition stage.

Michopoulos, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: mipa@fria.gr
Baloutsos, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: gb@nn.gr
Economou, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: ae@nn.gr

Category : Research note

article id 269, category Research note

Christian Kiffner, Elisabeth Rössiger, Oliver Trisl, Rainer Schulz, Ferdinand Rühe. (2008). Probability of recent bark stripping damage by red deer (Cervus elaphus) on Norway spruce (Picea abies) in a low mountain range in Germany – a preliminary analysis. Silva Fennica vol. 42 no. 1 article id 269. https://doi.org/10.14214/sf.269

Keywords: forest management; logistic regression; wildlife management

Abstract | View details | Full text in PDF | Author Info

Red deer (Cervus elaphus) can cause considerable damage to forest stands by bark stripping. Here, we examined the probability of bark stripping of susceptible Norway spruce (Picea abies) during winter in relation to local environmental characteristics in the western Harz Mountains, Lower Saxony, Germany. We present the results of a multiple logistic regression model for recent bark stripping damage by red deer which we developed from two systematic cluster sampling inventories after two winter periods along with associated meteorological data and records of bagged deer. Our model suggests that the risk of bark stripping increased significantly (P 0.05) with rising slope angle, cumulating snow depth and increasing index values of red deer population density. Spruces growing in closed forest stands were debarked at a higher probability than spruces located close to forest edges. Further on, spruce stands on eastern slopes had a lower probability of bark damage than spruce stands on northern slopes. Other tested variables (altitude, length of daily solar irradiation, duration of snow cover, age of spruce stand within the age range of 16–50 years) had no significant effect on the probability of new bark stripping. We conclude that red deer in the western Harz Mountains seem to use bark as food resource at preferred locations and in times of low food availability. To improve fit and predictive power of bark stripping models we recommend including stand characteristics. We propose to reduce the population size of red deer in order to diminish bark stripping damages to an economically acceptable level.

Kiffner, University Göttingen, Büsgen-Institute, Department of Forest Zoology and Forest Protection incl. Wildlife Biology and Game Management, Büsgenweg 3, 37077 Göttingen, Germany E-mail: ckiffne@gwdg.de
Rössiger, University Göttingen, Büsgen-Institute, Department of Forest Zoology and Forest Protection incl. Wildlife Biology and Game Management, Büsgenweg 3, 37077 Göttingen, Germany E-mail: er@nn.de
Trisl, Planungsbüro Trisl, In der Schleene 7, 36037 Waake, Germany E-mail: ot@nn.de
Schulz, University Göttingen, Büsgen-Institute, Department of Ecological Informatics, Biometry and Forest Growth, Büsgenweg 4, 37077 Göttingen, Germany E-mail: rs@nn.de
Rühe, University Göttingen, Büsgen-Institute, Department of Forest Zoology and Forest Protection incl. Wildlife Biology and Game Management, Büsgenweg 3, 37077 Göttingen, Germany E-mail: fr@nn.de

article id 268, category Research note

Adam Boratynski, Katarzyna Marcysiak, Amelia Lewandowska, Anna Jasinska, Grzegorz Iszkulo, Jaroslaw Burczyk. (2008). Differences in leaf morphology between Quercus petraea and Q. robur adult and young individuals. Silva Fennica vol. 42 no. 1 article id 268. https://doi.org/10.14214/sf.268

Keywords: morphological diversity; plant variation; biometry; Quercus; leaf polymorphism

Abstract | View details | Full text in PDF | Author Info

The characters of Quercus robur and Q. petraea leaves are of main taxonomic value and the adult trees of both species can be distinguished on them. However, young individuals, mostly seedlings but also saplings, are told to be undistinguishable or only partly distinguishable on the leaf morphology. The aim of the study was to verify this hypothesis on the basis of biometrical analyses of leaf characteristics of adults trees and saplings in two mixed oak woods, one located close to the north-eastern limit, the other about 400 km inside of the Q. petraea range in Poland. The analysis of discriminations and minimum spanning tree on the squares of Mahalanobis distances were analysed to find differences between Q. robur, Q. petraea and intermediate adults and saplings. The differences between saplings of Q. robur and Q. petraea were found lower than between adult trees. Nevertheless, the biometrical analysis confirmed determination of saplings in the field.

Boratynski, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland E-mail: borata@man.poznan.pl
Marcysiak, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: km@nn.pl
Lewandowska, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: al@nn.pl
Jasinska, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland E-mail: aj@nn.pl
Iszkulo, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland E-mail: gi@nn.pl
Burczyk, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: jb@nn.pl

Category : Discussion article

article id 270, category Discussion article

Seppo Rouvinen, Jari Kouki. (2008). The natural northern European boreal forests: unifying the concepts, terminologies, and their application. Silva Fennica vol. 42 no. 1 article id 270. https://doi.org/10.14214/sf.270

Keywords: human influence; biodiversity; natural ecosystems; natural forests; protection; terminology

Abstract | View details | Full text in PDF | Author Info

Recent emphasis on conserving the biodiversity has stressed the value of natural ecosystems in saving the species from extinction. In the Fennoscandian region the conifer-dominated boreal forests form the largest single ecosystem. The forests have been under varying intensity of human influence for decades or centuries. Recent attempts have tried to seek the last remaining natural forests to be included in the protection programmes. However, due to long and widespread human influence, finding and defining the natural forests has proven to be extremely difficult, not only because they are so rare but also because the concept of natural forest is vague. These difficulties are partly seen through the diverse terminology used. We first review the varying terminology as seen in recent studies. Secondly, we propose the basis for defining the natural forest and show some intriguing and challenging difficulties are involved in the concept. These difficulties are at least partly related to inherent strong and long-term dynamic component in boreal forest ecosystems that is manifested over several temporal and spatial scales. Finally, we outline a more general terminology with associated indicators and measurements that might be used in the classification and terminology. Conceptual clarification is necessary, for example, to compile ecologically justified and representative global, national and regional forest statistics. Many currently applied definitions of “forest” and “natural” that are applied in the context of forest statistics overlook ecologically important components of natural forests, and thus provide quite misleading or inadequate data of existing diversity patterns in these ecosystems.

Rouvinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: sr@nn.fi
Kouki, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: jari.kouki@joensuu.fi

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