Category: Research article
article id 464, category Research article
Regional energy wood logistics – optimizing local fuel supply. Silva Fennica vol. 43 no. 1 article id 464. https://doi.org/10.14214/sf.464
The promotion of electric energy production from solid biomass by the Austrian government has lead to a boom in the construction of new combined heat and power plants. The current total demand for wood chips in the research area for energy purposes is 70 400 m3 of loose volume chips per year. The expected increase in demand due to these new plants is more than 4 times greater than current demand: up to 302 700 m3 of loose volume per year. Even if the energy wood feedstock potential is satisfactory, the design of the supply chain is still unresolved. The aim of this study is to give decision-makers a base for further development. To accomplish this, we designed and tested four different supply scenarios: one for 9 plants and one for 16 plants. The scenarios were developed using a combination of geographic information systems (GIS) and linear programming methods. The results indicate that direct transport of solid fuel wood as round wood and chipping at the plant is the cheapest supply system with a resulting cost of 5.6–6.6 EUR/m3 loose. Using harvesting residues can only be recommended for large plants because of poor fuel quality. In this case, residues would be chipped at or near the landing, piled and transported via self-loading trucks at a cost between 8.4 and 9.1 EUR/m3 loose. In order to meet increasing demand and to ensure a continuous supply, especially during the winter and spring seasons it is necessary to optimize the supply chain by including storage terminals. However, using terminals and increased demand both lead to higher logistical costs. For example, if the total volume is handled via terminals, the average supply costs including storage will increase by 26%. Higher demand increases the costs by 24%.
article id 222, category Research article
Population, economic welfare and holding size distribution of private forestland in Alabama, USA. Silva Fennica vol. 43 no. 1 article id 222. https://doi.org/10.14214/sf.222
This paper analyzes structural differences in holding size distribution of private forestland at the county level in Alabama, USA. The following categories are used to describe the timberland holding distribution: mean holding size, Gini coefficient of timberland holdings, and share of county timberland in holding sizes of fewer than 80 hectares and more than 800 hectares. Regressions are conducted to explore the socio-economic correlates of forestland holding size distribution. Results indicate that population density, age structure, urban-rural population structure, income structure and land tenure type are strongly associated with the forest holding size distribution.
article id 221, category Research article
Impacts of forest harvesting related soil disturbance on end-of-rotation wood quality and quantity in a New Zealand radiata pine forest. Silva Fennica vol. 43 no. 1 article id 221. https://doi.org/10.14214/sf.221
The long-term effect of soil disturbance (litter removal, topsoil removal and compaction) from forest harvesting on wood quality and quantity of second-rotation Pinus radiata growing on a clay loam soil, was assessed at the end the rotation, 26 years after planting. Relative to Control plots, average tree and stand total volume at rotation end was not significantly affected by litter removal and nil or light compaction, but was significantly reduced by 28% by litter and topsoil removal and moderate subsoil compaction, and further reduced by 38% by heavy compaction. Wood density at breast height in the inner rings of trees in the most disturbed treatments was elevated by up to 30 kg m–3. This occurred because these treatments were more N deficient as reflected by foliar N levels during the first 11 years of growth relative to the Control. However, no treatment differences in wood density were evident in outer rings, and by rotation age overall mean density did not differ significantly between treatments. Neither acoustic velocity of standing trees, nor acoustic velocity of logs, was significantly affected by soil disturbance, indicating that stiffness of lumber cut from trees in the trial was likely to be similar for all treatments. Economic impacts of soil disturbance and compaction on this soil type will therefore result largely from the considerable negative impacts on final tree size, with little or no compensation from improved wood properties.
article id 220, category Research article
Energy wood thinning as a part of stand management of Scots pine and Norway spruce. Silva Fennica vol. 43 no. 1 article id 220. https://doi.org/10.14214/sf.220
The effects of combined production of industrial and energy wood on yield and harvesting incomes, as well as the feasibility of energy wood procurement, were studied. Data for 22 Scots pine (Pinus sylvestris L.) and 21 Norway spruce (Picea abies (L.) Karst.) juvenile stands in Central and Southern Finland were used to compare six combined production regimes to conventional industrial wood production. The study was based on simulations made by the MOTTI stand simulator, which produces growth predictions for alternative management regimes under various site and climatic conditions. The combined production regimes included precommercial thinning at 4–8 m dominant height to a density of 3000–4000 stems ha–1 and energy wood harvesting at 8, 10 or 12 m dominant height. Combined production did not decrease the total yield of industrial wood during the rotation period. Differences in the mean annual increment (MAI) were small, and the rotation periods varied only slightly between the alternatives. Combined production regime can be feasible for a forest owner if the price of energy wood is 3–5 EUR m–3 in pine stands, and 8–9 EUR m–3 in spruce stands. Energy wood procurement was not economically viable at the current energy price (12 EUR MWh–1) without state subsidies. Without subsidies a 15 EUR MWh–1 energy price would be needed. Our results imply that the combined production of industrial and energy wood could be a feasible stand management alternative.
article id 219, category Research article
The assessment of the uncertainty of updated stand-level inventory data. Silva Fennica vol. 43 no. 1 article id 219. https://doi.org/10.14214/sf.219
Predictions of growth and yield are essential in forest management planning. Growth predictions are usually obtained by applying complex simulation systems, whose accuracy is difficult to assess. Moreover, the computerised updating of old inventory data is increasing in the management of forest planning systems. A common characteristic of prediction models is that the uncertainties involved are usually not considered in the decision-making process. In this paper, two methods for assessing the uncertainty of updated forest inventory data were studied. The considered methods were (i) the models of observed errors and (ii) the k-nearest neighbour method. The derived assessments of uncertainty were compared with the empirical estimates of uncertainty. The practical utilisation of both methods was considered as well. The uncertainty assessments of updated stand-level inventory data using both methods were found to be feasible. The main advantages of the two studied methods include that bias as well as accuracy can be assessed.
article id 218, category Research article
Analyzing the effects of inventory errors on holding-level forest plans: the case of measurement error in the basal area of the dominated tree species. Silva Fennica vol. 43 no. 1 article id 218. https://doi.org/10.14214/sf.218
Accurate inventory data are required for ensuring optimal net return on investment from the forest. Erroneous data can lead to the formulation of a non-optimal plan that can cause inoptimality losses. Little is known of the effect of using erroneous stand inventory data in preparing holding-level forest plans. This study reports on an approach for analyzing such inoptimality losses. Furthermore, inoptimality losses caused by measurement errors in the basal area of the dominated tree species were investigated in a case study. Based on the inventory data including routine measurements by 67 measurers, four measurer groups were created with different measurement error profiles for the basal area of the dominated tree species. This was followed by measurement error simulations for each group and by adding these to the accurate control inventory data to create erroneous data of different error profiles. Three different forest plans were then constructed by using erroneous data of each group. The plans were then analyzed and compared with plans based on correct data. The effect of measurement errors on the net present value from the whole planning period, and on the amount of remaining growing stock at the end of planning period, were analyzed and utilized in calculating the inoptimality losses. It was concluded that even errors involving dominated tree species can cause significant changes in the holding-level forest plans.
article id 217, category Research article
Variation in the results of Norway spruce planting and Scots pine direct seeding in privately-owned forests in southern Finland. Silva Fennica vol. 43 no. 1 article id 217. https://doi.org/10.14214/sf.217
This study describes the variation in the planting results for 3-year-old Norway spruce (Picea abies (L.) Karst.) and 4-year-old Scots pine (Pinus sylvestris L.) using direct seeding in privately-owned regeneration areas in southern Finland. The study material consists of operative forest regeneration quality management inventory areas from the years 2000–2006. The effect of both the regional and the administrative levels as well as ecological factors was modelled on the basis of the hierarchy structure forestry centre, Forest Owners’ Association (= FOA), forestry professional, regeneration area and sample plot. The major part of the variation occurred at the sample plot and regeneration area level. Particular attention was paid to observation of the clustered spatial distribution of Scots pine seedlings. The FOA and forestry professional levels explained 5% of the variation in Norway spruce planting and 11% of the variation in Scots pine direct seeding. Applied forest regeneration operations, site and soil characteristics were included in the fixed effects. In the planting of Norway spruce the most important factor explaining the regeneration result was soil preparation. Mounding produced better results than patching and disc trenching. The site and soil characteristics were other important factors in the operations. The selection of direct seeding of Scots pine on too fertile, fine textured or moist sites yielded poor results.
article id 216, category Research article
Differences in stand characteristics between brook-side key habitats and managed forests in southern Finland. Silva Fennica vol. 43 no. 1 article id 216. https://doi.org/10.14214/sf.216
Preservation of small habitat patches termed as “woodland key habitats” or “especially important habitats” in the Finnish Forest Act has become an integral part of biodiversity-oriented forest management. Forest Act habitats belong to particular habitat types defined in the act, and they are supposed to have natural-like stand characteristics. However, very little is known about the actual stand structure in the designated habitats. Our aim was to compare stand characteristics between brook-side key habitats and comparable managed forests as controls. Seven study areas were selected from four regions across southern Finland. Within each study area ten key habitats and ten controls (140 stands) were randomly selected. Living and dead trees and cut stumps were measured in each stand within a 0.2 ha plot. The average degree of previous cutting was significantly lower whereas the volume of dead wood, volume of deciduous trees, and stand diversity were each significantly higher in key habitats than controls. The average volume of dead wood was 11.7 m3 ha–1 in key habitats and 6.5 m3 ha–1 in controls. However, there was considerable variation among individual stands, and a large part of key habitats could not be distinguished from randomly selected control stands with respect to stand characteristics. The preservation of natural brook channels with their immediate surroundings is undoubtedly important for maintaining aquatic and semiaquatic biodiversity. Nevertheless, when complementing the forest conservation network in the future, main emphasis in selecting potentially valuable stands should be placed on important structural features such as dead wood and old trees.
article id 215, category Research article
The growth rhythm and height growth of seedlings of Siberian (Larix sibirica Ledeb.) and Dahurian (Larix gmelinii Rupr.) larch provenances in greenhouse conditions. Silva Fennica vol. 43 no. 1 article id 215. https://doi.org/10.14214/sf.215
The aim of this study was to determine whether the growth rhythm and height growth differ between various larch provenances grown in greenhouse conditions. We also investigated whether the geographic and climatic conditions at the origin of the provenance could explain the possible differences between the provenances. The study material consisted of 16 Russian Siberian (Larix sibirica Ledeb.) and Dahurian larch (Larix gmelinii Rupr.) provenances and four seed sources from Finland as comparison lots. The growth rhythm differences were clearest between the southern and northern provenances; the southern provenances grew for a longer period and the proportion of late summer height growth was larger. Autumn colouration also developed later in these provenances. In the Russian larch material the provenances with a longer growing period had greater height growth. In the whole material the relationship was not so linear due to the deviating behaviour of the comparison material. Several of the Russian larch provenances were taller than the Finnish comparison seed lots, although the difference was not statistically significant. However, the growth of these provenances must be followed for a much longer period in field trials before any conclusions can be drawn about their usability in practical forestry.
article id 214, category Research article
Frost heaving of Picea abies seedlings as influenced by soil preparation, planting technique, and location along gap-shelterwood gradients. Silva Fennica vol. 43 no. 1 article id 214. https://doi.org/10.14214/sf.214
The effects of soil preparation, planting technique and location along gap-shelterwood gradients (position and orientation) on frost heaving damage to seedlings were studied in Vindeln Experimental Forests, northern Sweden. The forest was harvested in a grid pattern in winter 2004–2005, forming gaps and shelterwood areas of 30 x 40 m each. Gap-shelterwood gradients were delimited in four orientations and subdivided into five positions: 7 m and 15 m into the gap and shelterwood, and at the gap edge. At each position, three replicates of three soil preparations were made: exposed E and B horizons and HuMinMix (milled vegetation and humus layers mixed with surface mineral soil). In early October 2005, one-year-old containerized Picea abies (L.) Karst. seedlings were planted using four techniques: normal and deep planting, and mobile and fixed experimental containers. After one winter, frost heaving damage was highest for seedlings on B horizon combined with the mobile container (51 ± 6%) and normal planting (43±6%). Normal- or deep-planted seedlings in HuMinMix had the least damage (5–6.6 ± 2.5%). Compared to normal planting, deep planting reduced frost heaving damage only on B horizon. When considering the orientation, seedlings in the experimental containers had more or similar frost heaving damage than normal- or deep-planted seedlings. Along the eastern gradient, seedlings incurred more frost heaving damage in the center of the gap than under the canopy.
Category: Research note
article id 223, category Research note
Physiological effects of ingesting eucalyptus essential oil with milk casein peptide. Silva Fennica vol. 43 no. 1 article id 223. https://doi.org/10.14214/sf.223
This study was conducted to clarify the effect of eucalyptus essential oil mixed with milk casein peptide food for human physiological relaxation. Fifteen male university students (21.2 ± 0.9 yr) participated in study as subjects. The subjects were given one of two types of experimental drink (peptide + eucalyptus flavor (Pep + EF), and peptide + grapefruit·orange flavor (Pep + G·O), each flavor contains natural essential oil). We measured the change in salivary cortisol concentration and POMS scores before and two hours after taking experimental drink. The results of a Type A behavior pattern test were used to classify subjects. The concentration of salivary cortisol decreased significantly two hours after taking Pep + EF. And Type B showed bigger change than Type A. In conclusion, the results show that eucalyptus essential oil has the effect of relaxation, and that the effects on Type A and Type B are different.