Estimating forest data for analyses of forest production and utilization possibilities at local level by means of multi-source National Forest Inventory     

Helena Mäkelä  Hannu HirveläTuula Nuutinen  Leena Kärkkäinen 《Forest Ecology and Management》2011,262(8):1345-1359

The sample plot data of National Forest Inventories (NFI) are widely used in the analysis of forest production and utilization possibilities to support national and regional forest policy. However, there is an increasing interest for similar impact and scenario analyses for strategic planning at the local level. As the fairly sparse network of field plots only provides calculations for large areas, satellite image data have been applied to produce forest information for smaller areas. The aim of this study was to test the feasibility of generating forest data for a Finnish forest analysis tool, the MELA system, by means of the Landsat satellite imagery and the NFI sample plot data. The study was part of the preparation of a local forestry programme, where a strategic scenario analysis for the forest area of two villages (ca 8000 ha) was carried out. Management units that approximate forest stands were delineated by image segmentation. Stand volume and other parameters for each forest segment were estimated from weighted means of the NFI sample plots, where the individual sample plot weights were estimated by the k nearest neighbour (kNN) method. Two different spectral features were tested: single pixel values and average pixel values within a segment. The estimated forest data were compared with the forest data based on independent stand-level field assessments in two subareas, a national park and an area of forest managed for timber production.In the national park, the estimated mean volume of the growing stock from both spectral feature sets (about 160 m³ ha⁻¹) was clearly lower than that obtained from stand-level field assessment (186 m³ ha⁻¹). Using average pixel values within a segment resulted in a higher proportion of pine and a lower proportion of spruce volume than using single pixel values. It also resulted in an estimated felling potential nearly 10% higher over the first 10-year period in the scenario analysis of the area dedicated to timber production. However, the maximum long-term sustainable removal was at the same level (about 30,000 m³ year⁻¹) for both feature sets over the simulated 30-year period. The resulting annual felling area in the first 10-year period was 12% lower when the segment averages were applied, but the difference subsequently levelled off. The kNN approach in estimating initial forest data for scenario analyses at the local level was found promising.  相似文献   

Elevated temperature effects on germination and early growth of European aspen (Populus tremula), hybrid aspen (P. tremula × P. tremuloides) and their F2-hybrids     

Pertti Pulkkinen  Lu-Min Vaario  Leena Koivuranta  Niina Stenvall 《European Journal of Forest Research》2013,132(5-6):791-800

This study aimed to understand the interaction between temperature and genotype in terms of the effect on early seedling development of European aspen (Populus tremula) and various F₂-aspen hybrids. We evaluated the response of 16 different European aspen and F₂-hybrid families on seed germination, survival rate and seedling height in one- and two-family trials under three different temperature regimes. In one-family trials, higher germination and higher survival rates were observed in higher temperature (C1700), leading to taller seedlings. European aspen × hybrid aspen individuals (Asp × Hyb) had a higher survival rate and taller seedlings than Asp, Hyb × Asp or Hyb × Hyb individuals. The difference between Asp × Hyb and Hyb × Asp was pronounced. Both growth conditions and genotype (i.e., hybrid cross) had strong effects on germination, survival rate and height of European aspen and F₂-hybrid seedlings. However, the interaction of genotype and growth conditions also had a significant influence on survival rate and seedling height, but not on germination. Two-family trials involving European aspen and F₂-hybrids led to significant negative effects on germination and survival rate and also facilitation effects on seedling height. Similarly, genotype had strong effects on germination and survival rate. Different genotypes and traits affected survival rate and seedling height differently in different growth conditions. These differences were more pronounced in the warmest environment, i.e., 1,700 degree days. We conclude that introgression between F₂-hybrids and local European aspen is likely in the current climate, and any warming will likely favor certain F₂-hybrids, especially the most probable types (P. tremula × (P. tremula × P. tremuloides)).  相似文献   

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