Baltrušaitis A. and Aleinikovas M. 2012. Early-Stage Prediction and Modelling Strength Properties of Lithuanian-Grown Scots Pine (Pinus sylvestris L.). Baltic Forestry 18(2): 328-334

The aim of this article is to determine the distribution of Lithuanian pine wood according to the international strength classes and to establish correlations of roundwood and sawn timber viscous-elastic properties. At least 6 model trees from Scots pine (Pinus sylvestris L.) stands were selected in seven forest regions of Lithuania, representing typical growing sites. Comparative non-destructive methodology was used for the analysis of sawn timber taken from the model logs focused on modulus of elasticity, strength and the distribution into strength classes. The non-destructive tests were done using the Timber Grader MTG and Metriguard, used for measuring the log and sawn timber mechanical properties and bending machine. After performance of non-destructive log and sawn timber tests the static 4 – point bending test was done for boards out of tested logs. The comparison of modulus of elasticity of all static and dynamic devices with the actual timber bending strength was done after all the testings.

Keywords: Scots pine, wood strength, modulus of elasticity, non-destructive methods.

Hämäläinen, K. and Kärki, T. 2012. Usability of Wood as a Direct Printing Medium. Baltic Forestry 18(2): 316-327

Versatility in the appearance of wood and added value to interior decoration markets could be achieved by printing grain patterns of different species or images directly onto wood. The problem is how to transfer a high quality image or print sustainably onto wood, which is porous, heterogeneous, dimensionally unstable, non-white and rough. The surface properties of wood affect its printability. Optimal adhesion is essential for print quality, as too high ink absorbance can cause spreading and too low ink absorbance pale prints. Different printing techniques have different requirements on materials and production. Non-impact printing techniques provide the best basis for wood printing. Direct printing on wood has potential to provide efficiency to production. Inkjet printing on wood with different mechanical or chemical surface treatments, and wood plastic composite material gave good results that encourage further studies on the subject. Sanding the wood surface perpendicular to the grain gave the best overall printing quality. Spreading parallel to the grain could not be avoided totally, except in cases where the wood was treated hydrophobic, when in turn the adhesion of ink was not sufficient. The grain pattern of the underlying wood stayed clearly visible in the printed images.

Keywords: wood veneer, WPC, adhesion, printing, ink.

Tullus, A. *, Lukason, O., Vares, A., Padari, A. Lutter, R., Tullus, T., Karoles, K. and Tullus, H. 2012. Economics of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) and silver birch (Betula pendula Roth.) plantations on abandoned agricultural

We analysed the economics of hybrid aspen and silver birch which are both fast-growing deciduous trees recommended for the establishment of plantations on abandoned agricultural lands in Northern Europe. If managed during one rotation period the internal rate of return (IRR) of hybrid aspen plantations was 4.4-7.3% and the IRR of silver birch plantations was 4.7-6.7%. The highest value of IRR of 8.1% was estimated for the two-rotation (26+26 years) hybrid aspen management scenario in excellent site conditions. Higher IRR values were reached at excellent quality sites whereas hybrid aspen was more sensitive to site quality. With land cost included in the analysis, 1.1-1.7% lower IRR values were obtained compared to the case where land cost was excluded from the analysis, but the ranking of scenarios did not change. The financial maturity ages of one-rotation scenarios corresponding to maximum expected IRR values were 26 or 34 years for hybrid aspen in excellent or good to moderate sites respectively, whereas the maturity age did not change with the inclusion of land in the analysis. The maturity ages for different silver birch scenarios varied in the range of 34-45 years. The land expectation values (LEV) remained positive in case of 1-5% discount rates. In case of 3% discount rate, LEVs of all scenarios were roughly comparable to the current median agricultural land price. We conclude that the establishment of plantations with both studied hardwoods can be a profitable investment in Northern Europe and to ensure greater profitability such plantations should be managed under shorter rotations than traditionally used for birch and aspen forests in the region.

Keywords: abandoned agricultural lands, afforestation, deciduous trees, forest economics, hybrid aspen, internal rate of return, land expectation value, plantation forestry, short-rotation fore.ry, silver birch.

Hansson, K.*, Külvik, M. Bell, S. and Maikov, K. 2012. A Preliminary Assessment of Preferences for Estonian Natural Forests. Baltic Forestry 18(2): 299-315

Forests are a major element of the Estonian landscape and are visited by many people for recreational purposes. This article explores the Estonian natural forest environment from an aesthetic point of view. Previous studies have shown that natural landscapes are preferred over artificial, man-altered landscapes, yet little is known about preferences within natural settings in Estonia, where the forest forms an important aspect of the culture. The study reported here aimed to test the preferences for different natural forest stand structures using photographs shown to 97 participants. The evaluation was based on the environmental preference matrix of coherence, complexity and mystery formulated by Kaplan and Kaplan (1982, 1989), the photos being assessed for these factors by experts before the preference survey took place. Other elements were also evaluated to see which respondents found most attractive or unattractive and which might affect preference. The results were analysed to see which factors best explained preferences. Similarities between expert-group and lay-person assessments of predictor variables were also examined. Mystery proved to be statistically the strongest predictors of preference followed by coherence, as expressed by the test subjects, although the most preferred scenes were rated by experts as having high levels of coherence, showing some differences between experts and non-experts. The elements which most negatively affected preference were signs of death and decay as well as natural untidiness. This suggests that features inherent to natural landscapes and natural processes are not well understood or appreciated by the test population and that more information could be provided explaining why these are necessary parts of the natural landscape.

Keywords: visual landscape perception, human-landscape interaction, environmental preference, natural forest views, naturalness of environment.

Fyodorov, F. V. * and Yakimova, A. E. 2012. Changes in Ecosystems of the Middle Taiga due to the Impact of Beaver Activities, Karelia, Russia. Baltic Forestry 18(2): 278-287

Ecological consequences of beaver activity at water-bodies in southern Karelia were assessed. Vegetation succession induced by beaver foraging and construction activity was studied; the effect of long-term forest flooding on invertebrate and small mammal fauna. Beaver foraging activity results in the loss of 23.2 to 92.1% of aspen, 3.0 to 26.5% of birch and nearly all willow from the riparian plant community. Beaver dam construction induces the formation of wetland communities of mixed categories, including Sphagnum communities getting overgrown with birch, sedge-Sphagnum, Sphagnum-cotton grass, and various dwarf shrub-Sphagnum communities dominated by one or another dwarf shrub species. Organic carbon and the total nitrogen content in the soils of former beaver ponds increases, whereas pH decreases (Sidorova and Fyodorov 2007). The abundance and species composition of invertebrate and small mammal fauna also change significantly within the drained pond area. The number of invertebrates at beaver ponds increases 2 – 2½ times. Expansion of the terrestrial invertebrate fauna goes along with increase in its species and age diversity. In some surveys, the abundance of small mammals dropped nearly 10 times – from 7.0 animals per trap-day in reference plots to 0.67 in abandoned beaver sites. In other surveys, the abundance of shrews and voles increased 2-2.5 times.

Keywords: Beaver activities, changes of riparian ecosystems, forest vegetation, community, small mammals, invertebrates, plant.