期刊文献+
共找到55篇文章
< 1 2 3 >
每页显示 20 50 100
Novel uses of ensiled biomasses as feedstocks for green biorefineries
1
作者 Marketta Rinne 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第3期945-955,共11页
Perennial forage plants are efficient utilizers of solar radiation and nutrients so that there is a lot of scope to increase the production of green biomass in many areas.Currently,grasses are mainly used as feeds for... Perennial forage plants are efficient utilizers of solar radiation and nutrients so that there is a lot of scope to increase the production of green biomass in many areas.Currently,grasses are mainly used as feeds for ruminants and equines,but there could be higher added value use for several components of the green biomass.Interest in green biorefin-ing has risen recently motivated by the increased sustainability pressures and need to break the reliance on fossil fuels.Novel products derived from grass,such as paper and packaging,nanofibers,animal bedding,novel protein feeds,extracted proteins,biochemicals,nutraceuticals,bioactive compounds,biogas and biochar could create new sustainable business opportunities in rural areas.Most green biorefinery concepts focus on using fresh green biomass as the feedstock,but preservation of it by ensiling would provide several benefits such as all-year-around avail-ability of the feedstock and increased stability of the press juice and press cake.The major difference between fresh and ensiled grass is the conversion of water soluble carbohydrates into fermentation end products,mainly lactic and acetic acids,that lower the pH of the silage so that it becomes stable in anaerobic conditions.This has some important consequences on the processability and quality of products,which are partly positive and partly negative,e.g.,degradation of protein into peptides,amino acids and ammonia.These aspects are discussed in this review. 展开更多
关键词 ADDITIVE FERMENTATION Liquid-solid separation Protein SILAGE
下载PDF
Disentangling the effects of management and climate change on habitat suitability for saproxylic species in boreal forests
2
作者 Ellinoora Ekman María Triviño +3 位作者 Clemens Blattert Adriano Mazziotta Maria Potterf Kyle Eyvindson 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第2期121-133,共13页
Forest degradation induced by intensive forest management and temperature increase by climate change are resulting in biodiversity decline in boreal forests.Intensive forest management and high-end climate emission sc... Forest degradation induced by intensive forest management and temperature increase by climate change are resulting in biodiversity decline in boreal forests.Intensive forest management and high-end climate emission scenarios can further reduce the amount and diversity of deadwood,the limiting factor for habitats for saproxylic species in European boreal forests.The magnitude of their combined effects and how changes in forest management can affect deadwood diversity under a range of climate change scenarios are poorly understood.We used forest growth simulations to evaluate how forest management and climate change will individually and jointly affect habitats of red-listed saproxylic species in Finland.We simulated seven forest management regimes and three climate scenarios(reference,RCP4.5 and RCP8.5)over 100 years.Management regimes included set aside,continuous cover forestry,business-as-usual(BAU)and four modifications of BAU.Habitat suitability was assessed using a speciesspecific habitat suitability index,including 21 fungal and invertebrate species groups.“Winner”and“loser”species were identified based on the modelled impacts of forest management and climate change on their habitat suitability.We found that forest management had a major impact on habitat suitability of saproxylic species compared to climate change.Habitat suitability index varied by over 250%among management regimes,while overall change in habitat suitability index caused by climate change was on average only 2%.More species groups were identified as winners than losers from impacts of climate change(52%–95%were winners,depending on the climate change scenario and management regime).The largest increase in habitat suitability index was achieved under set aside(254%)and the climate scenario RCP8.5(>2%),while continuous cover forestry was the most suitable regime to increase habitat suitability of saproxylic species(up to+11%)across all climate change scenarios.Our results show that close-to-nature management regimes(e.g.,continuous cover forestry and set aside)can increase the habitat suitability of many saproxylic boreal species more than the basic business-as-usual regime.This suggests that biodiversity loss of many saproxylic species in boreal forests can be mitigated through improved forest management practices,even as climate change progresses. 展开更多
关键词 BIODIVERSITY Simulations FINLAND Forest planning Habitat suitability DEADWOOD
下载PDF
Predicting the provisioning potential of forest ecosystem services using airborne laser scanning data and forest resource maps 被引量:2
3
作者 Jari Vauhkonen 《Forest Ecosystems》 SCIE CSCD 2018年第3期325-343,共19页
Background: Remote sensing-based mapping of forest Ecosystem Service(ES) indicators has become increasingly popular. The resulting maps may enable to spatially assess the provisioning potential of ESs and prioritize t... Background: Remote sensing-based mapping of forest Ecosystem Service(ES) indicators has become increasingly popular. The resulting maps may enable to spatially assess the provisioning potential of ESs and prioritize the land use in subsequent decision analyses. However, the mapping is often based on readily available data, such as land cover maps and other publicly available databases, and ignoring the related uncertainties.Methods: This study tested the potential to improve the robustness of the decisions by means of local model fitting and uncertainty analysis. The quality of forest land use prioritization was evaluated under two different decision support models: either using the developed models deterministically or in corporation with the uncertainties of the models.Results: Prediction models based on Airborne Laser Scanning(ALS) data explained the variation in proxies of the suitability of forest plots for maintaining biodiversity, producing timber, storing carbon, or providing recreational uses(berry picking and visual amenity) with RMSEs of 15%–30%, depending on the ES. The RMSEs of the ALS-based predictions were 47%–97%of those derived from forest resource maps with a similar resolution. Due to applying a similar field calibration step on both of the data sources, the difference can be attributed to the better ability of ALS to explain the variation in the ES proxies.Conclusions: Despite the different accuracies, proxy values predicted by both the data sources could be used for a pixel-based prioritization of land use at a resolution of 250 m~2, i.e., in a considerably more detailed scale than required by current operational forest management. The uncertainty analysis indicated that maps of the ES provisioning potential should be prepared separately based on expected and extreme outcomes of the ES proxy models to fully describe the production possibilities of the landscape under the uncertainties in the models. 展开更多
关键词 Forestry decision making Spatial prioritization Light detection and ranging(LiDAR) Remote sensing
下载PDF
On the Possible Contribution of Natural Climatic Fluctuations to the Global Warming of the Last 135 Years 被引量:1
4
作者 Maxim Ogurtsov Markus Lindholm Risto Jalkanen 《Atmospheric and Climate Sciences》 2017年第3期256-262,共7页
A number of numerical experiments with artificial random signals (the second order autoregressive processes), which have important statistical properties similar to that of the observed instrumental temperature (1850-... A number of numerical experiments with artificial random signals (the second order autoregressive processes), which have important statistical properties similar to that of the observed instrumental temperature (1850-2015), were carried out. The results show that in frame of the selected mathematical model the return period of climatic events, analogous to the current global warming (linear increase of temperature for 0.95°C during the last 135 years) is 2849-5180 years (one event per 2849-5180 years). This means that global warming (GW) of the last 135 years can unlikely be fully explained by inherent oscillations of the climatic system. It was found however, that natural fluctuations of climate may appreciably contribute to the GW. The return period of climatic episodes with 0.5°C warming during the 135 years (half of the observed GW) was less than 500 years. The result testifies that the role of external factors (emission of greenhouse gases, solar activity etc.) in the GW could be less than often presumed. 展开更多
关键词 Global WARMING Climate NATURAL Oscillations
下载PDF
Using Individual, ApoE Genotype-Based Dietary and Physical Activity Advice to Promote Healthy Lifestyles in Finland—Impacts on Cardiovascular Risk Markers
5
作者 Hanna-Leena Hietaranta-Luoma Kari Akerman +2 位作者 Raija Tahvonen Hannu Puolijoki Anu Hopia 《Open Journal of Preventive Medicine》 2015年第5期206-217,共12页
Aim: There is increasing demand for individualized health advice. The aim of this study was to assess the effects on cardiovascular risk markers of receiving personal genetic health information, using apoE genotypes a... Aim: There is increasing demand for individualized health advice. The aim of this study was to assess the effects on cardiovascular risk markers of receiving personal genetic health information, using apoE genotypes as a tool for promoting lifestyle changes. ApoE was chosen because it had a significant impact on lipid metabolism and cholesterol absorption, all factors for CVD. Methods: This study was a one-year explanatory intervention study for healthy adults, aged between 20 - 67 years old (n = 106). Their clinical markers (serum lipids, blood glucose, blood pressure, Body Mass Index, body fat percentage and waist circumference) were measured three times during the intervention. The clinical effects were assessed for three groups: a high risk group (ε 4+, n = 16);a low-risk group (&#949?4-, n = 35);and a control group (n = 55). Results: The triglyceride values and waist circumference lowered more in &#949?4+ compared with the control group (p < 0.05;alpha value 0.005) during the intervention. Conclusion: The personal genetic information, based on apoE, may have positive effects on cardiovascular risk markers (e.g., improvement in triglyceride values). The individual health information, based on genotyping could be a potential option in the prevention of CVD. More research is required on how to utilize genotype-based health information in the prevention of lifestyle-related diseases. 展开更多
关键词 Genetic Information APOE INTERVENTION Healthy Lifestyle Cardiovascular Risk Markers
下载PDF
The national forest inventory in China:history-results-international context 被引量:8
6
作者 Wei Sheng Zeng Erkki Tomppo +1 位作者 Sean P.Healey Klaus V.Gadow 《Forest Ecosystems》 SCIE CSCD 2015年第4期288-303,共16页
Background: National forest resource assessments Inventories (NFI's), constitute an important nationa and monitoring, commonly known as National Forest information infrastructure in many countries. Methods: This ... Background: National forest resource assessments Inventories (NFI's), constitute an important nationa and monitoring, commonly known as National Forest information infrastructure in many countries. Methods: This study presents details about developments of the NFI in China, including sampling and plot design and the uses of alternative data sources, and specifically · reviews the evolution of the national forest inventory in China through the 20th and 21st centuries, with some reference to Europe and the US; · highlights the emergence of some common international themes: consistency of measurement; sampling designs; implementation of improved technology; expansion of the variables monitored more efficient scientific transparency;· presents an example of how China's expanding NFI exemplifies these global trends. Results: Main results and important changes in China's NFI are documented, both to support continued trend analysis and to provide data users with historical perspective. Conclusions: New technologies and data needs ensure that the Chinese NFI, like the national inventories in other countries, will continue to evolve. Within the context of historical change and current conditions, likely directions for this evolution are suggested. 展开更多
关键词 China EUROPE USA National forest inventories Forest inventory and analysis
下载PDF
Effect of Bacillus amyloliquefaciens and Bacillus subtilis on fermentation, dynamics of bacterial community and their functional shifts of whole-plant corn silage 被引量:10
7
作者 Jie Bai Marcia Franco +8 位作者 Zitong Ding Lin Hao Wencan Ke Musen Wang Dongmei Xie Ziqian Li Yixin Zhang Lin Ai Xusheng Guo 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2022年第3期864-877,共14页
Background:Bacillus amyloliquefaciens(BA)and Bacillus subtilis(BS)are usually used as feed supplements directly or bacterial inoculants in biological feeds for animals.However,few research have reported the effects of... Background:Bacillus amyloliquefaciens(BA)and Bacillus subtilis(BS)are usually used as feed supplements directly or bacterial inoculants in biological feeds for animals.However,few research have reported the effects of BA and BS on fermentation characteristics and bacterial community successions of whole-plant corn silage during ensiling.If the BA and BS inoculants have positive effects on silages,then they could not only improve fermentation characteristics,but also deliver BA or BS viable cells to ruminants,which would play its probiotic effect.Therefore,the objectives of this study were to investigate the effects of BA and BS on the fermentation,chemical characteristics,bacterial community and their metabolic pathway of whole-plant corn silage.Results:Freshly chopped whole-plant corn was inoculated without or with BA and BS,respectively,and ensiled for1,3,7,14 and 60 d.Results showed that BA and BS inoculations increased lactic acid concentrations of whole-plant corn silages compared with control,and BA inoculation decreased acetic acid concentrations,whereas BS inoculation decreased fiber contents and increased crude protein(CP)content.Higher water-soluble carbohydrate contents and lower starch contents were observed in BA-and BS-inoculated silages compared with that in control.The decreased CP content and increased non-protein nitrogen content were observed in BA-inoculated silage,which was consistent with the higher amino acid metabolism abundances observed in BA-inoculated silage.In addition,it was noteworthy that BA and BS inoculations increased the metabolism of cofactors and vitamins,and decreased the relative abundances of drug resistance:antimicrobial pathways.We also found that the bacterial metabolism pathways were clearly separated into three clusters based on the ensiling times of whole-plant corn silage in the present study.There were no significant differences in bacterial community compositions among the three groups during ensiling.However,BA and BS inoculations decreased the relative abundances of undesirable bacteria such as Acetobacter and Acinetobacter.Conclusion:Our findings suggested that the BS strain was more suitable as silage inoculants than the BA strain in whole-plant corn silage in this study. 展开更多
关键词 Bacillus silage inoculants Function prediction Silage quality Zea mays
下载PDF
乙酰化半纤维素用于提高涂布纸张的性能 被引量:1
8
作者 赵梦晓 Pekka SALMINEN +5 位作者 Martti TOIVAKKA Vinay KUMAR Chunlin XU Wenyang XU Risto KORPINEN 付时雨 《造纸科学与技术》 2019年第1期27-33,共7页
从云杉中经热水抽提出的聚半乳糖葡萄糖甘露糖(GGM)乙酰化后具有一定水溶性。将其涂布于食品包装纸上,结果表明GGM和乙酰化GGM均可提高食品包装纸的力学性能,且乙酰化GGM对力学性能的作用更好,涂有GGM和乙酰化GGM的纸有很好的耐油性能,... 从云杉中经热水抽提出的聚半乳糖葡萄糖甘露糖(GGM)乙酰化后具有一定水溶性。将其涂布于食品包装纸上,结果表明GGM和乙酰化GGM均可提高食品包装纸的力学性能,且乙酰化GGM对力学性能的作用更好,涂有GGM和乙酰化GGM的纸有很好的耐油性能,且涂乙酰化GGM比涂GGM的纸具有更好的耐油性。 展开更多
关键词 半纤维素 乙酰基化半纤维素 涂布 阻隔性能
下载PDF
The ruminal microbiome associated with methane emissions from ruminant livestock 被引量:18
9
作者 Ilma Tapio Timothy J.Snelling +1 位作者 Francesco Strozzi R.John Wallace 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2017年第2期289-299,共11页
Methane emissions from ruminant livestock contribute significantly to the large environmental footprint of agriculture.The rumen is the principal source of methane, and certain features of the microbiome are associate... Methane emissions from ruminant livestock contribute significantly to the large environmental footprint of agriculture.The rumen is the principal source of methane, and certain features of the microbiome are associated with low/high methane phenotypes. Despite their primary role in methanogenesis, the abundance of archaea has only a weak correlation with methane emissions from individual animals. The composition of the archaeal community appears to have a stronger effect, with animals harbouring the Methanobrevibacter gottschalki clade tending to be associated with greater methane emissions. Ciliate protozoa produce abundant H_2, the main substrate for methanogenesis in the rumen,and their removal(defaunation) results in an average 11% lower methane emissions in vivo, but the results are not consistent. Different protozoal genera seem to result in greater methane emissions, though community types(A, AB, B and O) did not differ. Within the bacteria, three different ‘ruminotypes' have been identified, two of which predispose animals to have lower methane emissions. The two low-methane ruminotypes are generally characterized by less abundant H_2-producing bacteria. A lower abundance of Proteobacteria and differences in certain Bacteroidetes and anaerobic fungi seem to be associated with high methane emissions. Rumen anaerobic fungi produce abundant H_2 and formate, and their abundance generally corresponds to the level of methane emissions. Thus, microbiome analysis is consistent with known pathways for H_2 production and methanogenesis, but not yet in a predictive manner. The production and utilisation of formate by the ruminal microbiota is poorly understood and may be a source of variability between animals. 展开更多
关键词 Archaea Methane Microbiome Rumen
下载PDF
Optimal plot design in a multipurpose forest inventory 被引量:1
10
作者 Helena M.Henttonen Annika Kangas 《Forest Ecosystems》 SCIE CSCD 2016年第1期37-50,共14页
Background: We explore the factors affecting the optimal plot design (size and type as well as the subsample tree selection strategies within a plot) and their relative importance in defining the optimal plot desig... Background: We explore the factors affecting the optimal plot design (size and type as well as the subsample tree selection strategies within a plot) and their relative importance in defining the optimal plot design in amultipurpose forest inventory. The factors include time used to lay out the plot and to make the tree measurements within the plot, the between-plot variation of each of the variables of interest in the area, and the measurement and model errors for the different variables. Methods: We simulate different plot types and sizes and subsample tree selection strategies on measuredtest areas from North Lapland. The plot types used are fixed-radius, concentric and relascope plots. Weselect the optimal type and size first at plot level using a cost-plus-loss approach and then at cluster level byminimizing the weighted standard error with fixed budget. Results: As relascope plots are ve~/efficient at the plot level for volume and basal area, and fixed-radius plots for stems per ha, the optimal plot type strongly depends on the relative importance of these variables. The concentric plot seems to be a good compromise between these two in many cases. The subsample tree selection strategy was more important in selecting optimal plot than many other factors. In cluster level, the most important factor is the transfer time between plots. Conclusions: While the optimal radius of plots and other parameters were sensitive to the measurement times and other cost factors, the concentric plot type was optimal in almost all studied cases. Subsample tree measurement strategies need further studies, as they were an important cost factor. However, their importance to the precision was not as clear. 展开更多
关键词 SAMPLE PLOT Forest inventory MEASUREMENT COST LOSS
下载PDF
Trade-offs between wood production and forest grouse habitats in two regions with distinctive landscapes 被引量:1
11
作者 Helena Haakana Esa Huhta +1 位作者 Hannu Hirvelä Tuula Packalen 《Forest Ecosystems》 SCIE CSCD 2020年第2期274-289,共16页
Background:Forest management affects the viability of forest grouse populations,causing alterations to habitat quality.At the regional level,common targets for wood harvesting and safeguarding of specific habitats are... Background:Forest management affects the viability of forest grouse populations,causing alterations to habitat quality.At the regional level,common targets for wood harvesting and safeguarding of specific habitats are negotiated between various stakeholders.Analysing potential trade-offs between forest grouse habitats and wood production in the region could support resource-smart decision making.Methods:In this paper,we compiled trade-off curves represented as production possibility frontiers demonstrating the relationship between forest grouse habitat area and wood removal,using a Finnish forestry dynamics model and the Finnish Multi-Source National Forest Inventory.For the modelling of forest grouse habitats,a landscape-level occurrence model based on nationwide wildlife triangle census data was used.Five alternative forest scenarios in terms of wood removal were compiled for two study areas in Finland representing two different landscape structures.Results and conclusions:Results showed that impacts on forest grouse habitats were case-specific.In the southern study area,increasing the roundwood harvesting rate affected grouse habitats more strongly as forests were already fragmented for other land uses and became more spruce-dominated over time.If the maximum sustainable removal rate was implemented,predicted grouse habitat area was 55%less than in a no-removal scenario.In the eastern study area,a more heavily forested region,the decrease was far lower at 22%.Scenario results were also compared to levels of recorded(business as usual)wood removal and that envisaged by valid regional forestry programmes,and their sustainability in terms of grouse habitat area was discussed.The production possibility frontiers calculated in this study support the evaluation of the loss of suitable habitat caused by different wood harvesting rates,or vice versa,the economic cost of increasing habitat areas. 展开更多
关键词 Forest grouse Forest landscape Habitat model Production possibilities frontier Scenario analyses Wood production
下载PDF
Predicting stand age in managed forests using National Forest Inventory field data and airborne laser scanning 被引量:1
12
作者 Matti Maltamo Hermanni Kinnunen +1 位作者 Annika Kangas Lauri Korhonen 《Forest Ecosystems》 SCIE CSCD 2020年第3期579-589,共11页
Background: The aim of this study was to construct a nationwide stand age model by using National Forest Inventory(NFI) data and nationwide airborne laser scanning(ALS) data. In plantation forestry, age is usually kno... Background: The aim of this study was to construct a nationwide stand age model by using National Forest Inventory(NFI) data and nationwide airborne laser scanning(ALS) data. In plantation forestry, age is usually known.While this is not the case in boreal managed forests, age is still seldom predicted in forest management inventories.Measuring age accurately in situ is also very laborious. On the other hand, tree age is one of the accurately measured sample tree attributes in NFI field data. Many countries also have a nationwide coverage of airborne laser scanning(ALS) data. In this study, we merged these data sources and constructed a nationwide, area-based model for stand age.Results: While constructing the model, we omitted old forests from the data, since the correlation between ALS height metrics and stand age diminished at stands with age > 100 years. Additionally, the effect of growth conditions was considerable, so we also utilized different geographical and NFI variables such as site fertility and soil type in the modeling. The resultant nationwide model for the stand age of managed forests yielded a root mean square error(RMSE) of about 14 years. The model could be improved further by additional forest structure variables, but such information may not be available in practice.Conclusions: The results showed that the prediction of stand age by ALS, geographical and NFI information was challenging, but stil possible with moderate success. This study is an example of the joint use of NFI and nationwide ALS data and re-use of NFI data in research. 展开更多
关键词 Forest stock age LIDAR NFI Nationwide model Growth conditions
下载PDF
How do nitrogen-limited alpine coniferous forests acquire nitrogen?A rhizosphere perspective 被引量:1
13
作者 Huajun Yin Bartosz Adamczyk +5 位作者 Qitong Wang Biao Zhu Wanji Guo Xiaomin Zhu Qing Liu Ziliang Zhang 《Forest Ecosystems》 SCIE CSCD 2022年第6期745-754,共10页
Background:Alpine coniferous forest ecosystems dominated by ectomycorrhizal(ECM)tree species are generally characterized by low soil nitrogen(N)availability but stabilized plant productivity.Thus,elucidating potential... Background:Alpine coniferous forest ecosystems dominated by ectomycorrhizal(ECM)tree species are generally characterized by low soil nitrogen(N)availability but stabilized plant productivity.Thus,elucidating potential mechanisms by which plants maintain efficient N acquisition is crucial for formulating optimized management practices in these ecosystems.Methods:We summarize empirical studies conducted at a long-term field monitoring station in the alpine coniferous forests on the eastern Tibetan Plateau,China.We propose a root-soil interaction-based framework encompassing key components including soil N supply,microbial N transformation,and root N uptake in the rhizosphere.Results:We highlight that,(i)a considerable size of soil dissolved organic N pool mitigates plant dependence on inorganic N supply;(ii)ectomycorrhizal roots regulate soil N transformations through both rhizosphere and hyphosphere effects,providing a driving force for scavenging soil N;(iii)a complementary pattern of plant uptake of different soil N forms via root-and mycorrhizal mycelium-pathways enables efficient N acquisitions in response to changing soil N availability.Conclusions:Multiple rhizosphere processes abovementioned collaboratively contribute to efficient plant N acquisition in alpine coniferous forests.Finally,we identify several research outlooks and directions to improve the understanding and prediction of ecosystem functions in alpine coniferous forests under on-going global changes. 展开更多
关键词 Plant nitrogen acquisition Root-soil interaction Alpine coniferous forests Nitrogen limitation RHIZOSPHERE
下载PDF
Early Snowmelt Enhances the Carbon Sequestration of Hummock-Forming Sphagnum Mosses on Boreal Wetlands 被引量:1
14
作者 Niko Silvan Kari Jokinen 《Open Journal of Ecology》 2016年第3期103-112,共10页
Sphagnum mosses are globally important owing to their considerable peat-forming ability and their potential impact on global climatic cycles acting as a long-term net carbon sink. However, changes in climatic conditio... Sphagnum mosses are globally important owing to their considerable peat-forming ability and their potential impact on global climatic cycles acting as a long-term net carbon sink. However, changes in climatic conditions due to global warming may affect the relations between Sphagnum mosses and vascular plants but also the competition among Sphagnum, and thus alter the accumulation of carbon on boreal wetlands. Sphagnum mosses are a plant genus with a favorable ability to grow in low solar irradiance and temperature conditions compared to vascular plants. This may be increasingly beneficial in increased wintertime temperatures and predated snowmelt conditions. To understand particularly the importance of early spring photosynthetic activity and thus the role of the length of growing season on carbon balance, we analyzed the CO<sub>2</sub> exchange of Sphagnum mosses with closed chamber technique in two categories of microtopographical habitats, hummocks and lawns, during four seasons 2010-2013 on a raised bog in Central Finland. During CO<sub>2</sub> exchange measurements, instantaneous net ecosystem exchange (NEE) and ecosystem respiration (RE) were measured. Our results show that the mean measured seasonal NEE, i.e. the instantaneous net carbon sequestration, of hummocks was generally only slightly higher than the NEE of lawns, but the mean measured seasonal RE of hummocks was clearly and significantly higher than the RE of lawns in every study year. A reason for the observed still higher seasonal carbon sequestration of hummocks than that of lawns besides the slightly higher rate of carbon accumulation was the longer duration of physiologically active growing season. Therefore, hummock-forming Sphagnum mosses exposed firstly from snow cover showed to get the extra time for photosynthesis and thus extra benefit compared to other mire plants. This may be further enhanced by the expansion of hummock-forming Sphagnum moss dominated raised bogs towards northern aapa-mire region due to the global warming. 展开更多
关键词 Sphagnum Mosses Boreal Wetlands Mire Microtopography Carbon Dynamics Global Warming
下载PDF
Sclerotia Formation and Toxin Production in Large Sclerotial Aspergillus flavus Isolates from Kenya 被引量:1
15
作者 S. A. Okoth B. Nyongesa +3 位作者 V. Joutsjoki H. Korhonen V. Ayugi E. K. Kang’ethe 《Advances in Microbiology》 2016年第1期47-56,共10页
We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ... We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ability to form sclerotia on different growth media. PCR analysis was done on the isolates to detect 2 structural genes, aflD and aflQ, involved in aflatoxin biosynthesis pathway. Positive A. flavus isolates for one or both genes were grown on Yeast Extract Sucrose Agar medium and aflatoxins quantified using LCMSMS. All the isolates formed large sclerotia and their formation was influenced by media type but could not be related to amount of aflatoxins produced both in vivo and in vitro. Though sclerotia are perennating structures and so contribute to survival index of a fungus, their initiation is regulated by external factors though ability to form is genetic. This brings ambiguity of their presence or abundance as a measure of toxicity. 展开更多
关键词 SCLEROTIA AFLATOXINS MAIZE Kenya Aspergillus flavus
下载PDF
Comparison of the local pivotal method and systematic sampling for national forest inventories
16
作者 Minna Räty Mikko Kuronen +3 位作者 Mari Myllymäki Annika Kangas Kai Mäkisara Juha Heikkinen 《Forest Ecosystems》 SCIE CSCD 2020年第4期716-732,共17页
Background:The local pivotal method(LPM)utilizing auxiliary data in sample selection has recently been proposed as a sampling method for national forest inventories(NFIs).Its performance compared to simple random samp... Background:The local pivotal method(LPM)utilizing auxiliary data in sample selection has recently been proposed as a sampling method for national forest inventories(NFIs).Its performance compared to simple random sampling(SRS)and LPM with geographical coordinates has produced promising results in simulation studies.In this simulation study we compared all these sampling methods to systematic sampling.The LPM samples were selected solely using the coordinates(LPMxy)or,in addition to that,auxiliary remote sensing-based forest variables(RS variables).We utilized field measurement data(NFI-field)and Multi-Source NFI(MS-NFI)maps as target data,and independent MS-NFI maps as auxiliary data.The designs were compared using relative efficiency(RE);a ratio of mean squared errors of the reference sampling design against the studied design.Applying a method in NFI also requires a proven estimator for the variance.Therefore,three different variance estimators were evaluated against the empirical variance of replications:1)an estimator corresponding to SRS;2)a Grafström-Schelin estimator repurposed for LPM;and 3)a Matérn estimator applied in the Finnish NFI for systematic sampling design.Results:The LPMxy was nearly comparable with the systematic design for the most target variables.The REs of the LPM designs utilizing auxiliary data compared to the systematic design varied between 0.74–1.18,according to the studied target variable.The SRS estimator for variance was expectedly the most biased and conservative estimator.Similarly,the Grafström-Schelin estimator gave overestimates in the case of LPMxy.When the RS variables were utilized as auxiliary data,the Grafström-Schelin estimates tended to underestimate the empirical variance.In systematic sampling the Matérn and Grafström-Schelin estimators performed for practical purposes equally.Conclusions:LPM optimized for a specific variable tended to be more efficient than systematic sampling,but all of the considered LPM designs were less efficient than the systematic sampling design for some target variables.The Grafström-Schelin estimator could be used as such with LPMxy or instead of the Matérn estimator in systematic sampling.Further studies of the variance estimators are needed if other auxiliary variables are to be used in LPM. 展开更多
关键词 Auxiliary data Bias Local pivotal method Matérn estimator National forest inventory Sampling efficiency Simple random sampling Spatially balanced sampling Systematic sampling Variance
下载PDF
Inventory of aspen trees in spruce dominated stands in conserva-tion area
17
作者 Matti Maltamo Annukka Pesonen +3 位作者 Lauri Korhonen Jari Kouki Mikko Vehmas Kalle Eerik?inen 《Forest Ecosystems》 SCIE CAS CSCD 2015年第2期143-154,共12页
Background: The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of... Background: The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging. Methods: We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes: volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collected from three separate forest stands in Koli National Park, eastern Finland. At each site, we measured breast height diameter and coordinates of each aspen. The comparison of inventory methods of aspens within the three stands was based on simulations with mapped field data. We mimicked stand level inventory by locating varying numbers of fixed area circular plots both systematically and randomly within the stands. Additionally, we also tested if the use of airborne laser scanning (ALS) data as auxiliary information would improve the accuracy of the stand level inventory by applying the probability proportional to size sampling to assist the selection of field plot locations. Results: The results showed that aspens were always clustered, and the diameter distributions indicated different stand structures in the three investigated forest stands. The reliability of the volume and number of large aspen trees varied from relative root mean square error figures above 50% with fewer sample plots (5-10) to values of 25%-50% with ]0 or more sample plots. Stand level inventory estimates were also able to detect spatial pattern and the shape of the diameter distribution. In addition, ALS-based auxiliary information could be useful in guiding the inventories, but caution should be used when applying the ALS-supported inventory technique. Conclusions: This study characterized European aspen populations for the purposes of monitoring and management of boreal conservation areas. Our results suggest that if the number of sample plots is adequate, i.e. 10 or more stand level inventory will provide accurate enough forest attributes estimates in conservation areas (minimum accuracy requirement of RMSE% is 20%-50%). Even for the more ecologically valuable attributes, such as diameter distribution, spatial pattern and large aspens, the estimates are acceptable for conservation purposes 展开更多
关键词 Diameter distribution Historical continuity INVENTORY LiDAR Populus tremula L Simulation Spatial arrangement Stand characteristics
下载PDF
Inter-and intra-seasonal effects of temperature variation on radial growth of alpine treeline Norway spruce
18
作者 Samuli HELAMA Raimo SUTINEN 《Journal of Mountain Science》 SCIE CSCD 2016年第1期1-12,共12页
A widely accepted standpoint contends that plant growth near the cold edge of the species range,such as treelines,does not depend on the annual temperature seasonality(i.e.difference between maximum and minimum temper... A widely accepted standpoint contends that plant growth near the cold edge of the species range,such as treelines,does not depend on the annual temperature seasonality(i.e.difference between maximum and minimum temperature values) but rather on the warmth of summer season.In contrast to this expectation,we show that the growth of treeline Norway spruce(Picea abies) is well explained by temperature seasonality as a single climatic determinant.To do so,the tree-ring data of spruce trees growing on alpine treeline in Lapland was compared with long climate records.Biennial time-series of temperature seasonality capture both the decadal and abrupt growth fluctuations with a correlation coefficient of r = 0.601.We also show that the archetypal association between summer temperature and treeline tree growth may in fact be by far a more complex relationship than previously thought.Spruce growth appears responsive to lateJune(r = 0.494) and mid-July(r = 0.310) temperatures but unresponsive to temperatures during the early July,that is,during the grand period of the tracheid formation.Climatic warming may enhance the treeline spruce growth unless the warming is concentrated on unresponsive interval in the midst of the growing season.Water relations did not play significant role as agents of P.abies growth. 展开更多
关键词 Annual temperature cycle Climaticextremes DENDROCLIMATOLOGY Plant-climate
下载PDF
Bridging mapping and simulation modelling in the ecosystem service assessments of boreal forests:effects of bioenergy production on carbon dynamics
19
作者 Anu Akujärvi Anna Repo +1 位作者 Altti M.Akujärvi Jari Liski 《Forest Ecosystems》 SCIE CSCD 2021年第1期35-49,共15页
Background:Increasing the use of forest harvest residues for bioenergy production reduces greenhouse emissions from the use of fossil fuels.However,it may also reduce carbon stocks and habitats for deadwood dependent ... Background:Increasing the use of forest harvest residues for bioenergy production reduces greenhouse emissions from the use of fossil fuels.However,it may also reduce carbon stocks and habitats for deadwood dependent species.Consequently,simple tools for assessing the trade-offs of alternative management practices on forest dynamics and their services to people are needed.The objectives of this study were to combine mapping and simulation modelling to investigate the effects of forest management on ecosystem services related to carbon cycle in the case of bioenergy production;and to evaluate the suitability of this approach for assessing ecosystem services at the landscape level.Stand level simulations of forest growth and carbon budget were combined with extensive multi-source forest inventory data across a southern boreal landscape in Finland.Stochastic changes in the stand age class distribution over the study region were simulated to mimic variation in management regimes.Results:The mapping framework produced reasonable estimates of the effects of forest management on a set of key ecosystem service indicators:the annual carbon stocks and fluxes of forest biomass and soil,timber and energy-wood production and the coarse woody litter production over a simulation period 2012–2100.Regular harvesting,affecting the stand age class distribution,was a key driver of the carbon stock changes at a landscape level.Extracting forest harvest residues in the final felling caused carbon loss from litter and soil,particularly with combined aboveground residue and stump harvesting.It also reduced the annual coarse woody litter production,demonstrating negative impacts on deadwood abundance and,consequently,forest biodiversity.Conclusions:The refined mapping framework was suitable for assessing ecosystem services at the landscape level.The procedure contributes to bridging the gap between ecosystem service mapping and detailed simulation modelling in boreal forests.It allows for visualizing ecosystem services as fine resolution maps to support sustainable land use planning.In the future,more detailed models and a wider variety of ecosystem service indicators could be added to develop the method. 展开更多
关键词 Carbon budget Ecosystem services Forest management Forest bioenergy Landscape level MAPPING MODELLING
下载PDF
A Study on Multi-Enriched Housing Environment in Blue Foxes
20
作者 Hannu T. Korhonen Pekka Eskeli 《Open Journal of Animal Sciences》 2015年第2期77-85,共9页
A traditional fox cage was furnished with both activating environmental enrichments (EE) (a bone, a scratching plate, a hockey buck, a ceiling rope and a wall rope and straw) and EEs enabling resting or observation (a... A traditional fox cage was furnished with both activating environmental enrichments (EE) (a bone, a scratching plate, a hockey buck, a ceiling rope and a wall rope and straw) and EEs enabling resting or observation (a wire-mesh platform and a top nest box). The aim was to find out to which extent blue foxes (Vulpes lagopus) utilized these EEs, and to collect practical experiences of the EEs. The experimental animals were 12 adult blue fox vixens that had been housed in cages furnished with a platform and a bone for about 1.5 years before they were transferred to the multi-enriched cages. The frequency and duration of the active contacts with the EEs were measured with continuous recording on Days 1, 2, 7 and 16 after the transfer, with three hours (13:30 - 14:30, 18:00 - 19:00 and 2:00 - 3:00) on each day. The total use of the EEs was 15 times per hour and more than 20% of the time. For most EEs both the time spent in contact and the frequency of contacts with the EEs declined steeply after Day 1, reflecting a novelty effect of the EEs. This decline was not so evident for the platform, top nest box and wall rope. These three EEs were also the ones used the most by the foxes. The ropes were badly damaged during the experiments, whereas other EEs remained in good condition. Explorativity markedly increased when animals were transferred from home cage to enriched cages. Explorativity remained high during entire study period when foxes were kept in enriched enrichment. Furthermore, it remained high also after transferring of animals back to home cages. Capture reaction was quite similar in home and enriched cages. The amount of stereotypy varied among recording days (P < 0.05). When foxes were transferred from home cages to multi-enriched cages, no change was found in the amount stereotypy during Days 1 and 2. Thereafter, the amount of stereotypy showed a declined trend. Stereotypy tended to increase when foxes were transferred back to home cages. Our results indicated that foxes used readily the opportunities for more diverse behaviours. 展开更多
关键词 VULPES lagopus ANIMAL WELFARE BEHAVIOUR ENVIRONMENTAL ENRICHMENT
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部