Carbon and nitrogen release from decomposing Scots pine,Norway spruce and silver birch stumps   总被引：1，自引：0，他引：1  

Marjo Palviainen  Leena Finér  Raija Laiho  Ekaterina Shorohova  Ekaterina Kapitsa  Ilkka Vanha-Majamaa 《Forest Ecology and Management》2010

Stumps are the largest coarse woody debris component in managed forests, but their role in nutrient cycling is poorly understood. We studied carbon (C) and nitrogen (N) dynamics in Scots pine (Pinus sylvestris), Norway spruce (Picea abies), and silver birch (Betula pendula) stumps, which had decomposed for 0, 5, 10, 20, 30 and 40 years after clear-cutting in southern Finland. Carbon and N were released significantly faster from birch stumps than from conifer stumps. In 40 years, conifer stumps lost 78% and birch stumps 90% of their initial C. In contrast, the amount of N in stumps increased, indicating that external N accumulated in the stumps. After 40 years of decomposition, the amount of N was 1.7 and 2.7 times higher than the initial amount in pine and spruce stumps, respectively. Nitrogen was released from birch stumps, but only after they had decomposed for 20 or more years. On average, 59% of N stored in birch stumps was released during 40 years. The results indicate that the stumps of the major tree species in Fennoscandian forests are long-term C and, especially, N pools which serve as N sinks, thus potentially diminishing N leaching into ground water and watercourses after harvesting. This suggests that the removal of stumps for bioenergy production may markedly affect the nutrient status and nutrient cycling of boreal forests.  相似文献   

Towards interactive fish farming governance? a comparison of Finland and Sweden     

Timo Mäkinen  Pekka Salmi  Leena Forsman 《Aquaculture International》2014,22(2):711-721

The neighbouring countries, Finland and Sweden, compete in the same market with their aquaculture. Both countries have had, until recently, stringent environmental policies limiting production volumes. During recent years, however, Swedish fish farmers have been able to increase their production volume, and Finnish fish farmers have also redirected their investments to Sweden. Thus, the strict Finnish environmental permit policy has not benefited the Baltic Sea environment, but has moved the production volumes and employment opportunities to other locations in the Baltic Sea and its drainage basin. By comparing the Finnish and Swedish fish farming governance systems, we found that in Sweden, various types of formal and informal interaction and practice have enhanced the achievement of balanced decisions. This has only rarely been the case in Finland, which features a more authoritative decision-making culture. On the other hand, increased communication across the Finnish administrative sectors raises future prospects for more holistic fish farming governance, which balances economic, social and environmental goals.  相似文献   

Edge effects and trampling in boreal urban forest fragments – impacts on the soil microbial community     

Minna Malmivaara-Lämsä  Leena Hamberg  Elli Haapamäki  Jari Liski  D. Johan Kotze  Susanna Lehvävirta  Hannu Fritze 《Soil biology & biochemistry》2008,40(7):1612-1621

Fragmentation of forest ecosystems increases the proportion of edge habitat and is accompanied by a change in plant species composition. The recreational use of urban forests leads to decreased vegetation cover and the formation of paths, and thus, to fragmentation at small scales. We studied the impacts of forest and path edge effects on the soil microbial community structure (by using the phospholipid fatty acid (PLFA) method) and microbial activity (measured as basal respiration) in 34 mesic boreal urban forest fragments in Finland. We sampled the humus layer 1) from the forest edge into the interior (0–80 m), and 2) at different distances from paths. Microbial community structure was only slightly affected by the forest edge but differences were found between distances of 0–10 m and over 50 m from the edge. These changes correlated with changes in soil pH. Although changes in the microbial community structure were not pronounced, microbial biomass and activity were 30–45% lower at the first 20 m into the forest fragments, due to a low moisture content of the humus near the edge. The decreased microbial activity detected at forest edges implies decreased litter decomposition rates, and thus, a change in ecosystem nutrient cycling. The microbial community structure differed between paths and surrounding areas and correlated with changes in soil pH. Paths also supported approximately 25–30% higher microbial biomass with a transition zone of at least 1 m from the path edge. Path associated disturbances (mainly alterations in vegetation and soil pH) were reflected in the soil microbial community structure up to 1.5 m from the paths.  相似文献   

Evaluation of the relationship between injuries and size of gestation stalls relative to size of sows     

Anil L  Anil SS  Deen J 《Journal of the American Veterinary Medical Association》2002,221(6):834-836

OBJECTIVE: To determine whether there is a relationship between sow injuries and size of gestation stalls relative to sow size. DESIGN: Prospective study. ANIMALS: 267 pregnant sows. PROCEDURE: Sows were randomly selected from 4 swine farms. Sow and stall measurements were obtained, and injuries were scored on the basis of location, number, and depth. Ratios of stall length to sow length and stall width to sow height were calculated. RESULTS: High injury scores were associated with low ratios of stall length to sow length and stall width to sow height. CONCLUSIONS AND CLINICAL RELEVANCE: A small increase in stall dimensions could reduce injuries and improve well-being of sows considerably.  相似文献   

Adherence of Staphylococcus intermedius to canine corneocytes in vitro   总被引：1，自引：1，他引：0  

Saijonmaa-Koulumies LE  Lloyd DH 《Veterinary dermatology》2002,13(4):169-176

This study investigated the in vitro adherence of Staphylococcus intermedius to canine corneocytes, collected from a healthy dog using double-sided adhesive tape. Adherence was shown to depend on duration (P < 0.001) and temperature of incubation (P < 0.001) and the concentration of bacteria (P < 0.001). Isolates of S. intermedius from lesions of pyoderma were not generally more adherent to healthy canine skin than were isolates from healthy dogs. Significant differences in adherence were demonstrated between individual isolates within both groups (P < 0.001). The study suggests that among S. intermedius there is no correlation between virulence and adherence to canine corneocytes in vitro. The finding may be important for the potential use of avirulent variants of S. intermedius as antagonistic strains against canine pyoderma. However, more studies are needed to compare the adherence of the isolates to skin cells obtained from dogs with diseases predisposed to pyoderma.  相似文献   

Effect of group size and structure on the welfare and performance of pregnant sows in pens with electronic sow feeders          下载免费PDF全文

Leena Anil  Sukumarannair S. Anil  John Deen  Samuel K. Baidoo    Roger D. Walker 《Canadian journal of veterinary research》2006,70(2):128-136

Pregnant sows were housed in dynamic, twice-mixed, and static groups of different sizes in pens with electronic sow feeders (ESFs) to study the effect of group size and structure on sow welfare and performance. The total injury score (TIS) was significantly higher (P < 0.05) in the dynamic group than in the other groups in general and 2 wk after mixing. The salivary cortisol concentrations were similar in the 3 groups. The frequency of queuing was significantly higher (P < 0.05) in the twice-mixed group and the frequency of nonagonistic social interactions significantly lower (P < 0.05) in the dynamic group. The total number of aggressive acts was positively and significantly correlated (P < 0.05) with the frequency and duration of queuing in all the groups. Farrowing performance and longevity did not differ between the groups. The higher TIS and lower number of nonagonistic social interactions indicated that welfare was compromised in the dynamic group as compared with the other groups.  相似文献   

Sexual Reproduction of European Aspen (Populus tremula L.) at Prescribed Burned Site: The Effects of Moisture Conditions     

Tarja Latva-Karjanmaa  Leena Suvanto  Kari Leinonen  Hannu Rita 《New Forests》2006,31(3):545-558

Aspen (Populus tremula) is capable of reproducing both sexually and asexually from root suckers, the latter being more common. Seedlings are rare even though potential seed production is enormous. The aim of this study was to find out how different moisture conditions affect emergence and survival of aspen seedlings on burned soil. We set up a sowing experiment on mineral soil and on humus. The sowing was done at 240 microsites (θ7 cm) in 15 blocks (1×1 m). Treatments were sowing time, watering and sowing shelter. A total of 1463 seedlings emerged on mineral soil and 26 on humus. Watering, covering, their interaction, block and sowing time had significant effects on the number of seedlings. The largest numbers of seedlings were recorded at microsites that were watered and covered. The survival of seedlings was 20% during the growing season and 45% over winter. We conclude that seedbed conditions and moisture are the most essential factors for sexual reproduction of aspen. Short-term weather conditions have an important effect on seedling emergence and are likely to greatly affect field studies.  相似文献   

The effect of red wood ant (<Emphasis Type="Italic">Formica rufa</Emphasis> group) mounds on root biomass,density, and nutrient concentrations in boreal managed forests   总被引：2，自引：1，他引：2  

Mizue Ohashi  Jouni Kilpeläinen  Leena Finér  Anita C. Risch  Timo Domisch  Seppo Neuvonen  Pekka Niemelä 《Journal of Forest Research》2007,12(2):113-119

Red wood ants (Formica rufa group, RWAs) are common insects in boreal forests in Fennoscandia, and they build large, long-lived mounds as their nests. RWA mounds are enriched with carbon and nutrients, but little information is available about how they affect root distribution and the nutrient uptake of trees. In this study, we investigated the biomass, biomass density, nutrient concentrations, and amounts of fine (<2 mm) and coarse (>2 mm) roots in RWA mounds, and compared them with those of surrounding forest soil in mixed coniferous stands of different age classes in Finland. Neither fine nor coarse root biomasses differed significantly between the aboveground parts of the mounds and the organic layer of the soil. Root biomass density was lower in mounds than in the organic layer. However, fine root biomass and biomass density were higher in the belowground parts of mounds than in the surrounding mineral soil. Macroelement (N, Ca, K, P, S, Mg) and Zn and Cu concentrations in roots in the mounds were significantly higher than those in the organic layer. Root biomass and biomass density did not differ between stands of different age classes. The results of this study indicate that RWA mounds increase heterogeneity in root distribution in forest ecosystems, and also increase the availability of nutrients for plants that extend their roots inside RWA mounds.  相似文献   

Irreversible diameter change of wood segments correlates with other methods for estimating frost tolerance of living cells in freeze-thaw experiment: a case study with seven urban tree species in Helsinki     

Anna Lintunen  Teemu Paljakka  Anu Riikonen  Leena Lindén  Lauri Lindfors  Eero Nikinmaa  Teemu Hölttä 《Annals of Forest Science》2015,72(8):1089-1098

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Delayed soil thawing affects root and shoot functioning and growth in Scots pine     

Repo T  Lehto T  Finér L 《Tree physiology》2008,28(10):1583-1591

In boreal regions, soil can remain frozen after the start of the growing season. We compared relationships between root characteristics and water relations in Scots pine (Pinus sylvestris L.) saplings subjected to soil frost treatments before and during the first week of the growing period in a controlled environment experiment. Delayed soil thawing delayed the onset of sap flow or totally blocked it if soil thawing lagged the start of the growing period by 7 days. This effect was reflected in the electrical impedance of needles and trunks and in the relative electrolyte leakage of needles. Prolonged soil frost reduced or completely inhibited root growth. In unfrozen soil, limited trunk sap flow was observed despite unfavorable aboveground growing conditions (low temperature, low irradiance, short photoperiod). Following the earliest soil thaw, sap flow varied during the growing season, depending on light and temperature conditions, phenological stage of the plant and the amount of live needles in the canopy. The results suggest that delayed soil thawing can reduce tree growth, and if prolonged, it can be lethal.  相似文献