Impacts of bucking and delimbing alternatives on pulpwood and energy wood yields in young thinning stands in Finland

The supply of energy wood from young forests could be enhanced by altering the harvesting methods in integrated pulpwood and energy wood thinnings. In this study, effects of different bucking and delimbing options on the biomass division into energy wood, pulpwood and logging residue were estimated in integrated thinnings of young stands dominated by Scots pine (Pinus sylvestris), Norway spruce (Picea abies) or birches (Betula spp.) in Finland. Thinning options were simulated in the harvestings of model stands created on the basis of forest inventory data. Increasing the minimum top diameter of pulpwood (MTDP) expectedly increased energy wood and decreased pulpwood yields. Depending on tree species, energy wood yield increased by 36–65% when the top diameter was increased from the regular level (6 or 7 cm) to 8 cm in whole-tree harvesting, and was more than doubled when the top diameter was increased to 10 cm. Delimbed energy wood yield was increased by 240–280% when the top diameter was increased to 10 cm. Total harvesting yield in whole-tree thinnings was slightly increased by increasing top diameter. These increments in harvesting yields and reallocations of tree biomass could have an impact on large-scale forest energy potentials.     

Effects of <Emphasis Type="Italic">Acacia seyal</Emphasis> and biochar on soil properties and sorghum yield in agroforestry systems in South Sudan

We studied the effects of Acacia seyal Del. intercropping and biochar soil amendment on soil physico-chemical properties and sorghum (Sorghum bicolor L.) yields in a two-year field experiment conducted on a silt loam site near Renk in South Sudan. A split-plot design with three replications was used. The main factor was tree-cropping system (dense acacia + sorghum, scattered acacia + sorghum, and sole sorghum) and biochar (0 and 10 Mg ha^?1) was the subplot factor. The two acacia systems had lower soil pH, N and higher C/N ratios compared to the sole sorghum system. Biochar significantly increased soil C, exchangeable K⁺ contents, field capacity and available water content, but reduced soil exchangeable Ca²⁺ and effective CEC, and had no effect on soil pH. Acacia intercropping significantly reduced sorghum grain yields while biochar had no significant effect on sorghum yields. The land equivalent ratio (LER) for sorghum yield was 0.3 for both acacia systems in 2011, with or without biochar, but increased in 2012 to 0.6 for the scattered acacia system when combined with biochar. The reduction in sorghum yields by the A. seyal trees was probably due to a combination of competition for water and nutrients and shading. The lack of a yield response to biochar maybe due to insufficient time or too low a dosage. Further research is needed to test for the effects of tree intercropping and biochar and their interactions on soil properties and crop yields in drylands.     

The number of pelagic fish in Lake Paasivesi,Finland, monitored by hydroacoustic methods

A Craig and Forbes algorithm-based computer program was used to make an acoustic estimate of the number of fish in the pelagic zone of Lake Paasivesi. The acoustic data were collected at night. More than 95% of the estimated fish were counted as singlefish echoes. The vertical distribution of the fish in May was uniform from 4 m down to the bottom, but in August about 90% of the fish counted were between 4 and 18 m. The total number of fish in the research area was 1.3 × 10⁶ individuals in May and 2.7 × 10⁶ individuals in August. The mean fish density was 260 and 530 fish ha^?1, respectively. The horizontal fish distribution in this lake is unusually uniform and the fish density unusually low in comparison with many other lakes in central Finland.     

Split root fertigation enhances cucumber yield in both an open and a semi-closed greenhouse

We investigated the hypothesis that split root fertigation (SRF) approach could provide complementary benefits over traditional fertigation (TF) in terms of water use, vegetative growth and yield formation in the high radiation season and under two atmospheric conditions in a greenhouse. Plants of cucumber (Cucumis sativus L. cv. Cumuli) were grown in a traditional high-wire cultivation system in a peat growing medium. In the SRF method the root system of a plant was separated into two compartments over the crop cycle. One compartment received fertigation solution with low EC (1.2 dS m⁻¹) and the other compartment solution with high EC (3.5 dS m⁻¹) value. In the TF method the EC value of fertigation solution was 2.4 dS m⁻¹. The atmospheric conditions included an open (ventilated) and a semi-closed (cooled) greenhouse. The employment of cooling resulted in an enhancement of the average CO₂ in a semi-closed (810 ppm) over an open (530 ppm) greenhouse resulting in a yield improvement (37%). SRF improved water uptake in both atmospheric conditions and water use efficiency (WUE) in an open greenhouse. The water uptake in SRF was highest in the root part with the low EC values, namely 61% in the open and 66% in the semi-closed greenhouse. In both atmospheric conditions, SRF decreased flower abortion, leading to an improved fruit set with a small effect on vegetative growth. SRF increased yield by 21% in the open and 17% in the semi-closed greenhouse compared to TF in corresponding greenhouses.     

Interaction between xylanase and a proton pump inhibitor on broiler chicken performance and gut function

Three hundred thirty-six Ross 308 male broiler chicks were used in a 21-d study to explore performance and gut function when treated with a proton pump inhibitor(PPI;0 or 89 mg/kg)in a 2×2 factorial arrangement with a xylanase(Xyl;0 or 0.1 g/kg)to determine if the beneficial activity of arabinoxylan(AX)depolymerisation,through arabinoxylo-oligosaccharides(AXOS)production,starts in the upper gastrointestinal tract.Treatment with the PPI started from d 14,and by d 21 animal performance had deteriorated(P<0.001).An interaction was observed between PPI and Xyl for feed conversion ratio(FCR)(P<0.05),whereby the combination reduced the negative effect of PPI on FCR.Application of PPI raised digesta pH in the gizzard and caecum(P<0.05),increased protein concentrations in the lower gut(P<0.05)and reduced intake of digestible nutrients(P<0.05).Caecal concentrations of indole,p-cresol,ammonia and the ratio of total volatile fatty acid(VFA)to butyric acid were increased with PPI(P<0.05),indicating enhanced protein fermentation.Xylanase activity in the digesta were greatest in the caeca,especially when Xyl was supplemented(P<0.001).The concentration of total soluble AX was greater in the gizzard and ileal digesta with Xyl supplementation(P<0.05),supporting the depolymerisation action of xylanase even under acidic conditions.These data suggest xylanase may function in the gizzard even though pH is not optimal for activity and emphasises the importance of chlorohydric acid secretions in ensuring overall optimum gut function.AX depolymerisation benefits animal performance although it is still unknown how the AXOS produced with xylanase supplementation in the upper gastrointestinal tract influence the microbial populations and overall gut functionality.     

Effects of Different Fat Supplements on Growth and Hepatic Lipids and Fatty Acids in Male Mink

Male mink kits (n=10 for each group) were fed diets supplemented with different fats for 12 weeks (September-November). The levels of digestible fat (8%) and energy content (7 MJ kg-1) of the diets were equal. The supplements used were beef pork fat, mink fat, broiler offal, rainbow trout offal, capelin oil, soybean oil and linseed oil. The growth and hepatic lipids (analysed by a thin-layer chromatography- flame ionization detection analyser) and fatty acid composition (analysed by gas-liquid chromatography) were studied. The pattern of weight gain of the mink fed the beef pork diet differed from that of the other mink. These kits reached high but delayed weight maxima compared with the other mink but then during November they lost weight rapidly. In liver, both the capelin oil- and linseed oil-fed mink had large concentrations of total lipids and triacylglycerols. The mink fed capelin oil were significantly heavier. The fatty acid analyses of hepatic total lipids and phospholipids revealed that the f -linolenic acid (18:3 n-3) of linseed oil was not efficiently metabolized to longer chain and more unsaturated fatty acids important for cellular membranes. It is discussed that 18:3 n-3 may not be as valuable for growing mink kits as the polyunsaturated fatty acids of the fish oils.     

Chemical Characterization of Metal-Contaminated Soil in Two Study Areas in Finland

Water, Air, & Soil Pollution - In the present work we studied the role of humic acids in the heavy metal–soil interaction after the addition of different amounts of humic acids to a soil...     

Impacts of trace amounts of labile C on plant N limitation vary from hour to week timescales

The ability of terrestrial ecosystems to store carbon (C) under rising atmospheric CO₂ will depend on how severely nitrogen (N) will limit plant growth. We tested whether increased C availability in the soil at elevated CO₂ could affect N limitation by inducing N release from soil organic matter (SOM). We established microcosms composed of Holcus lanatus plants, field soil (containing “old” SOM) and ¹⁵?N-labeled plant litter (representing “new” SOM), simulated different levels of root C release by adding a single pulse of 0, 18, 44, or 175?μg glucose C?g^?1 dry soil and recorded the effects on soil microbial biomass, microbial-feeding protozoa and nematodes and plant performance 1, 3, 9, and 32?days after C addition. The effects on H. lanatus growth and N uptake depended on the amount of added C and the time elapsed since addition. Shoot N concentration and N content were higher in pots amended with 44?μg?C g^?1 soil than in other pots 1?day after C addition. Later, 9 and 32?days after C addition, the highest glucose addition reduced the dry mass, N concentration, and N content of H. lanatus shoots in comparison to other treatment levels. Microbial biomass was generally higher in soils subjected to 44?μg glucose C?g^?1 soil than in control soils, and, at the last harvest, the numbers of protozoa were significantly higher in all soils with glucose amendments than in control soils. No effects on microbial-feeding nematodes were found, and plant N uptake from “old” and “new” SOM was equally affected by C addition. Our results seem to suggest that, while a low pulse of labile C can increase plant N uptake temporarily on an hour scale, higher amounts of C will intensify plant N limitation at timescales of days and weeks. Generalization of such dose and time dependent results requires great caution, but if verified in other plant–soil systems as well, they would suggest that plant N availability under elevated C availability may depend on the balance between positive and negative effects operating at different timescales and triggered by additional C pulses of varying size.     

Genetic variation of pedunculate oak (Quercus robur L.) in the urban woodlands of Helsinki

We present a genetic profile of pedunculate oak (Quercus robur L.) in three woodlands of the Helsinki region. We genotyped all mature trees and samples of seedlings to evaluate patterns of genetic variation and gene flow, and evaluate the long-term stability and natural regeneration of these stands. Although five microsatellite loci showed no significant differences in heterozygosity between generations in most locations, significant (p?per se does not interfere with gene flow over the distances represented here. Based on our findings, a minimal-maintenance program reliant upon natural regeneration of oak in the public parks of Helsinki seems plausible.     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.