Aina, K.S., Olayiwola, Y.B., Ogunleye, B.M. and Olusola, O.E. 2022. Influences of cement brands and mixing ratio on the physico-mechanical properties of cement bonded particleboards made of wood particles of Gmelina arborea, Afzelia africana and Triplochi
Cement bonded particleboards (CBPs) were produced of wood particles of Gmelina arborea, Afzelia africana and Triplochiton scleroxylon using two brands of ordinary portland cement manufactured by two different domestic cement companies operating in Nigeria known as Dangote PLC and Lafarge Company. The admixture of wood particles and cement for production of the CBPs were done at mixing ratio of 1:1, 1:1.5 and 1:2 (weight to weight basis). The properties such as water absorption and thickness swelling at 24 hours, density, modulus of rupture (MOR), modulus of elasticity (MOE) and impact bending strength were determined. The results of the study reveal that the density ranged from 0.61 to 0.92 g/cm3 . Meanwhile, water absorption and thickness swelling were found to be 30.34 to 72.44% and 11.43 to 10.77% at 24 hours, respectively. The bending properties obtained from the laboratory tests ranged from 115.77 to 826.55 N/mm2 and from 1,157.70 to 4,773.38 N/mm2 for MOR and MOE, respectively, while impact bending strength ranged from 41.70 to 238.49 N/mm2 , respectively. As the cementious content increases from 50% to 66.3% and wood content decreases from 50% to 33.4%, the properties such as density, MOR, MOE and impact bending strength increased, while water absorption and thickness swelling decreases. The statistical results showed that such factors as wood species, cement type and mixing ratio had significant influence on the physical and mechanical properties of CBPs. The study reveals that CBPs made of wood particles of Triplochiton scleroxylon and Dangote cement brand at the ratio of 1:2 were more dimensionally stable, denser and stronger while CBPs of wood particles of Afzelia africana were stiffest and most rigid. As concluded, cement brand had significant importance in qualities of CBPs, which can be attributed to chemical compositions found in materials used.
Keywords: cement, physical, mechanical, wood, particleboards, mixing ratio
Wijana, N., Citrawathi, D.M., Mulyadiharja, S., Julyasih, K.S.M. and Dewi, N.P.S.R. 2022. Results of ethnoecolo- gical studies in the prospect of forest tourism development in Tenganan Pegringsingan traditional village, Karangasem, Bali. Baltic Forestry 2
This study mainly discusses the lack of implementation of forest development as a tourist attraction in Karangasem, Bali, Indonesia. This research aims to implement the results of ethnoecological studies to develop the Bukit Kangin forest tourism in the traditional village of Tenganan Pegringsingan, Karangasem, Bali. The population in this study area is considered in two aspects, namely the ecosystem aspect and the socio-system one. The population of the ecosystem consists of all plant species in Bukit Kangin, while the population in the socio-system aspect is the entire community of Tenganan Pegringsingan traditional village. The sample of this research from the ecosystem aspect includes plant species covered by squares with a size of 20 × 20 meters including tree habitus (nature), 10 × 10 meters (which includes sapling), and squares with a size of 1 × 1 meters including seedling habitus. The number of squares is 65 squared. For the community sample, community components are selected with a total sample of 50 people. The ecosystem data collection uses the quadratic method with systematic sampling techniques. Meanwhile, the data collection is carried out by interview, observation sheets, and questionnaires. The data related to ecosystem was analysed using ecological statistical analysis, while the data related to the socio-system were analysed descriptively. Descriptive analysis was used to determine the prospects for forest tourism development. The conclusions of this study are the following: (1) the results of ethnoecological studies in the Bukit Kangin forest, Tenganan Pegringsingan village, Karangasem, Bali, has the prospect of being developed into forest tourism as an alternative and complementary tourist destination; (2) some of the results of ethnoecological studies and supported by socio-system that interact with each other can be in the form of plant species composition equipped with descriptions, utilization, processing methods and products of useful plant species. The results of ethnobotanical and ethnobiological studies are very supportive in the development of forest tourism in the Kangin hills, Tenganan Pegringsingan, Karang Asem, Bali.
Keywords: ethnoecological, forest tourism, Tenganan Pegringsingan
Kärenlampi, P.P. 2022. Empirical observations of the yield of logs from trees of the boreal region. Baltic Forestry 28(1): 117–122.
The yield of sawlogs and plywood logs from boreal trees is discussed. First, taper curves are used to compute geometric (maximal) sawlog and plywood log contents. Then, a quality reduction is implemented, according to previously published models. Finally, the outcome is verified using empirical observations. Regarding spruce trees, the different estimates of sawlog content agree. In the case of birch and pine trees, the estimates differ. The sawlog and plywood log yield from large trees is greater than prognosticated, probably due to missing over-aged trees in the empirical data. The yield of sawlogs and plywood logs from small trees is smaller than prognosticated, most of the empirical data originating from thinnings with a focus on the quality of the remaining trees. The sawlog content of individual trees from clearcutting displays a skew distribution around the expected value. The distribution in thinning trunks shows a binary component, with a large proportion of trees with zero sawlog content.
Keywords: sawlog, plywoodlog, Picea abies, Betula species, Pinus sylvestris
Jakubowski, M. and Praczyk, M. 2022. Weight loss of logwood piles stored under winter conditions in Poland. Baltic Forestry 28(1): 123–130.
Our work focuses on the natural drying of woods in winter. It aimed to compare the natural drying process of three wood species: Scots pine as coniferous species, sessile oak as ring-porous species with a marked heartwood and silver birch as a sapwood species with a diffuse-porous structure. The research was carried out in central Poland. We collected logs from a 41-year-old stand destined for thinning. We stacked the logs randomly in one pile. The experiment took place between November 30, 2016 and April 4, 2017. All the samples were measured individually every two days throughout the experiment. We found logs lost weight during the experiment, especially pine (12% of total mass), less so oak and birch (7%). We recorded the biggest decrease during the last month (in spring). The wood moisture content decreased the most in pine and the least in oak heartwood. The stepwise regression model explains the impact of weather at 58%. Relative humidity was the most significant factor (0.58), followed by temperature and wind. We observed that weight loss and diameter are related to different degrees in the tested species, which probably depends on the sapwood area. Our observations show that natural wood drying in winter is a slow process that speeds up in the spring.
Keywords: natural drying, woodpiles, wood storage, moisture content
Kalbarczyk, R., Ziemiańska, M., Kalbarczyk, E., Nieróbca, A. and Dobrzańska, J. 2022. Reduction determinants of Scots pine tree-ring width in the vicinity of Puławy industrial plants (central-eastern Poland). Baltic Forestry 28(1): 105–116.
Scots pine (Pinus sylvestris L.) is a tree species that reacts to meteorological conditions, industrial pollution and groundwater level. The aims of this study were to evaluate reductions and increases in Scots pine tree-ring widths (VTRW) as compared to reference sequences for sites in two types of forest habitat found in the vicinity of the chemical plant complex in Puławy, located in central-eastern Poland, and to determine the relationship between VTRW, climate and anthropogenic factors. A considerable reduction in tree-ring widths compared with reference sites was found for sites affected by chemical plant emissions from the end of the 1960s, i.e. right after the start of the Puławy industrial plants, to the beginning of the 1990s (implementation of new technologies). This period of reduction in tree-ring width lasted longer and was greater in magnitude in the pure Scots pine stands studied within a coniferous mixed forest habitat. Furthermore, the reduction in Scots pine tree- ring width was largely dependent on below-average air temperature in the period from December of the year preceding ring formation until January of the current year and above-average total precipitation from June until August above-average SO₂, NH₃ and NOx emissions and above-average surface and underground water withdrawals from company intakes. The influence of weather on VTRW was weakened by anthropogenic factors, which affected the quality of the local natural environment. Therefore, Scots pine tree-ring width may be used to evaluate the state of the natural environment and threats it is facing in areas with high levels of industrial pollution including, for example, SO₂, NH₃ and NOx.
Keywords: temperature and precipitation conditions, air pollution, tree-ring width, forest research area, dendroecological studies, Central Europe, Pinus sylvestris L.