The aim of the study was to determine the impact an increased wood supply from the Beskid forests after natural disasters on the timber economy of the Węgierska Górka Forest District and its ...surroundings in the years 2004–2010. The analysis was based on the wood raw material sales recorded in the database of the State Forestry Information System (SILP). Information on the buyers'location and their main use for the raw material were obtained through the Central Statistical Office. Furthermore, wood material buyers were classified according to the Polish Classification of Activities (PCA) based on the year 2007, using only a subjective analysis designed for enterprises and other economic units in the national economy.
Changes in sales of wood material to the selected buyer groups were investigated using statistical analyses of linear trends. A Pearson's correlation analysis verified the relationships between the buyer groups and the supply of timber assortments by the Węgierska Górka Forest District. Other studies have also shown that an increased supply of raw material in the context of natural disasters affects the types of wood buyers and their location. In addition, they have shown an increase in interest towards the purchase of raw materials among buyers engaged in the wholesale trade of wood and other non-wood producers which in turn decrease the share purchased by sawmills.
Trees harvested in cuttings are usually partitioned into timber assortments, for instance, saw logs, poles and pulpwood logs. Since different assortments have different prices, the way in which ...harvested stems are crosscut affects the incomes of the forest landowner. Optimal crosscutting aims at maximizing the total value of the assortments obtained from the stems. Although forest research has developed several algorithms for optimal crosscutting, it has rarely been included in the optimization of stand management. Treatment prescriptions are often based on analyses in which the value of harvested trees is calculated without considering the whole set of timber price categories and without simulating the crosscutting of harvested trees. This may lead to biased conclusions about optimal stand management. This study proposed a fast and flexible method for optimizing the crosscutting of harvested trees in the context of stand management optimization. The method employs simulated annealing to find the optimal combination of log lengths, separately for each harvested tree. The results calculated for case study stands suggest that optimal crosscutting leads to longer rotation lengths than obtained in analyses where the values of harvested trees are predicted with more simple methods. Optimal crosscutting increases the incomes of forest landowner and the proportions of the most valuable saw log assortments. The proportion of harvested pulpwood decreases.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The aim of the study was to determine the impact of increased timber logging after natural disasters on timber assortments, unit prices, as well as average prices of timber spruce and total timber. ...The net sales prices of the years 2004-2010, available from the database of the State Forests Information System (SFIS) for the Forest District of WÄgierska Górka, were analysed and compared to the prices of selected forest districts within the Regional Directorate of State Forests in Cracow (RDSF). The forest districts were classified based on the volume of logged timber leading to a separation into two groups of two and six forest districts. Moreover, we tested for significance in the linear trends of relevant characteristics and determined confidence intervals. Furthermore, we calculated the rate of growth (decrease) of the unit prices. Our studies show a decrease in price of only some of the timber assortments despite a significantly increased supply. Price declines were observed for the average prices of timber spruce and total timber due to their lowered quality. The price of timber assortments was mainly determined by effects of macroeconomic factors.
This study examines price dynamics in roundwood exports from Russia to Finland, the largest international roundwood trade flow within Europe. The analysis covers six main timber assortments; sawlog ...and pulpwood dimensions of pine, spruce and birch. The study period, starting from the devaluation of the rouble in August 1998, was characterized by a drastic increase in the volumes of Russian roundwood imported into Finland, and a coinciding structural change in the timber assortment distribution of the Finnish roundwood imports. A basic hypothesis of economic theory, the law of one price, was tested by using quarterly time series and methods of cointegration analysis. According to the cointegration tests, the prices of Finnish and Russian spruce sawlogs have moved closely together. Furthermore, the changes in the prices of spruce sawlogs in the Finnish roundwood market are reflected in the Russian prices and not vice versa. Regarding other timber assortments, price co-movement and consequent market integration was not detected.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In forestry practice, during forest harvesting there are many different situations while skidding timber assortments, which are dealt with individually depending on the circumstances.
The main ...purpose of this scientific paper is to offer a model for the calculation of the optimal distance for skidding timber assortments uphill or downhill, in mountain conditions. The working area i.e. the harvesting volume is situated between two storey (horizontal) forest roads. This solution would enable the forest experts to make the right decisions when planning timber assortment skidding, i.e. to achieve the most favorable financial results of the work.
The method is based on work efficiency i.e. the time required for skidding certain timber assortments (logs and firewood), when skidding is done by animals, adapted tractor equipped with winch, and mobile cable crane.
•Growth data of a 41-year trial of Chinese fir plantations.•Long-term effects of five different densities and four different site classes on timber assortment structure are explored.•Promoting effect ...of low density on large-diameter timber is enhanced as site quality increases.•The interaction between density and site index significantly affects the formation of large-diameter timber.•Significant effect of site index on large-diameter timber persists longer.
Stand density control coupled with site control is a key technique for cultivating large-diameter timber of Chinese fir trees, whose yield can be effectively increased by the optimal density and site management mode employed. This study aimed to evaluate the dynamic changes in timber assortment structure under differing initial planting densities and site quality based on growth data of a 41-year trial of Chinese fir plantations. Our results showed that the total timber yield and both large-diameter timber outturn and the outturn rate all increased with better site quality under the same initial planting density. Further, the outturn peak as well as outturn rate peak for both medium- and small-diameter timber was reached sooner with improved site quality. For the same site class, a lower initial planting density augmented the total timber outturn rate, and also resulted in less time required for the total timber outturn rate to reach a constant or maximum value. Finally, the total timber outturn rate of all density plots tended to be nearly identical. Using a high planting density increased the outturn of small-diameter timber, whose outturn peak was delayed in the denser plots. The bolstering effect of low density upon the growth of large-diameter timber was enhanced by higher site quality, with density-induced differences in large-diameter timber more pronounced; conversely, that promoting effect weakened under poor site quality conditions. The interaction between planting density and site index significantly influenced the growth of any timber assortment of Chinese fir in the early stage following its formation. Notably, the significant effect of site index on large-diameter timber lasted longer than that of other timber assortments. The optimal site conditions for cultivating large-diameter timber trees of Chinese fir consist of a site class ≥ 20 with a planting density limited to no more than 1667 trees/ha, whose stand rotation period must be over 26 years, so as to maximize the output of large-diameter timber yield. Our empirical findings will be helpful for the construction of an optimal cultivation mode for the density, site, and rotation age of large-diameter timber in Chinese fir plantations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The changes in diameter structure of Pinus sylvestris ( L. ) in addition to similar previous study on Pinus nigra ( Arn.) in mixed Austrian black pine – Scots pine plantations after damages from ...abundant wet heavy snow in the region of Velingrad – Northwest Rhodopes were studied. А period without significant abiotic influences (1997-2007) and following one (2007-2017) were compared, in which small-scale natural disaster caused by snowfalls was observed (2015). The analysis was made with variation distribution curves of the stems according to natural degrees of thickness. It is confirmed that the reason for deviations from the normality of the trees distribution is their right asymmetry as consequence of trees with smaller diameters loss as a sum result of the natural loss and the heavy snow. This is proved by analysis of the curves of mean variation rows for percent stem distribution according to natural degrees of thickness and Skewness and Kurtosis coefficients. The dynamics in the trees number distribution of both species forming the composition by Gini index was investigated as well as the diameter, height, basal area, volume and assortment structure.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Timber assortments are some of the most important goods provided by forests worldwide. To quantify the amount and type of timber assortment is strongly important for socio-economic purposes, but also ...for accurate assessment of the carbon stored in the forest ecosystems, regardless of their main function. Terrestrial laser scanning (TLS) became a promising tool for timber assortment assessment compared to the traditional surveys, allowing reconstructing the tree architecture directly and rapidly. This study aims to introduce an approach for timber assortment assessment using TLS data in a mixed and multi-layered Mediterranean forest. It consists of five steps: (1) pre-processing, (2) timber-leaf discrimination, (3) stem detection, (4) stem reconstruction, and (5) timber assortment assessment. We assume that stem form drives the stem reconstruction, and therefore, it influences the timber assortment assessment. Results reveal that the timber-leaf discrimination accuracy is 0.98 through the Random Forests algorithm. The overall detection rate for all trees is 84.4%, and all trees with a diameter at breast height larger than 0.30 m are correctly identified. Results highlight that the main factors hindering stem reconstruction are the presence of defects outside the trunk, trees poorly covered by points, and the stem form. We expect that the proposed approach is a starting point for valorising the timber resources from unmanaged/managed forests, e.g., abandoned forests. Further studies to calibrate its performance under different forest stand conditions are furtherly required.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Customer-oriented production as a sawmill strategy requires up-to-date information on the available raw material resources. Bucking is a process in which the tree stem is divided into products based ...on the roundwood user’s needs regarding products and their quality and dimensions. Optimization methods are employed in bucking to recover the highest value of the stem for a given product price matrix and requested length–diameter distribution. A method is presented here for assessing the value of harvestable timber stands based on their product yield. Airborne laser scanning, multispectral imagery, and field plots were used to produce timber statistics for a grid covering the target area. The statistics for the plots were generated from this grid. The value of the estimated tree list was assessed using a bucking-to-value simulator together with a stem quality database. Different product yield simulations in terms of volumes, timber assortment recoveries, wood paying capabilities (WPC) and value estimations based on the presented method, and extensive field measurements were compared. As a conclusion, this method can estimate WPC for pulpwood and sawlogs with root mean squared errors of 32.7% and 38.5%, respectively, relative to extensive field measurements.
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BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper deals with experience about the research project development with industry for the solution of specific problem. Nowadays most of higher educational institutions are particularly ...interested in implementing joint projects with industry, sharing experiences and resources to jointly develop new technologies and innovative products. In the University of Latvia within the framework of an effective collaboration projects program, a mutually beneficial shared cost system for the needs of scientists and businessmens is possible for solving the tasks of the both partners. Joint Stock Company Latvias State Forests were interested in development of an automatic volume measurement of logs and wood chip loads on trucks. To solve this problem, a methodology and a technological solution are needed to allow remotely perform volumetric surveys and monitoring. It is significant with the intense development of forest and logging industry. The system consists of measurement arch with video cameras and IT solution - video processing and analysis software, a graphical user interface, data communication channels and storage systems. Video information is obtained from cameras that simultaneously acquire raw data from the object of the video processing area - both sides and top. The information is transmitted to the external systems via data communication channels. The system will be used for automated volume measurement because in Latvia this process is currently performed by persons who manually measure loaded logs or wood chips on the trucks.
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