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  • Reyes, Teija (Hakapaino Oy, 2008)
    Forest destruction for agriculture continues to be a major threat to the rich biological diversity in the East Usambara Mountains in the north-eastern corner of Tanzania. The highest ratio of endemic plant and animal species found on 100 km2 anywhere in the world is depending on the remaining natural forests. Forests are vitally important for the local population in many different ways, and nationally they are an important source of water and hydroelectricity. The soils, of low fertility and mostly acidic Ferrasols, mainly have the nutrients in the topsoil. After clear-cutting, the soils soon become poor when the topsoil is eroded. High-value cardamom is nowadays unsustainably cultivated in the natural forests of the East Usambaras. The general aim was to study the possibilities to develop new profitable and sustainable agroforestry systems for the benefit of the local people that could contribute to relieving the pressure on the remaining natural forests in the East Usambara Mountains. Results from a spice crop agroforestry trial, established in cooperation with a local farmer, showed a clear advantage of intercropping cardamom (Elettaria cardamomum) and black pepper (Piper nigrum) with trees, especially with Grevillea robusta. The nitrogen fixing tree species Gliricidia sepium also improved the nitrogen and organic matter content of the soil over levels found in the natural forest. With improved agroforestry methods for spice production the households generated as much as13 times the net income obtained with traditional forest cultivation practices. There are thus sustainable and profitable ways to cultivate spices as cash crops in well-managed homegardens. However, the farmers need stable markets, access to credit and comprehensive extension services. The soil fertility depletion should be reversed with organic manure application and an enabling policy environment for the smallholder-farming sector. Strong farmers organisations and equal rights to resources and decision-making are needed. Organic spices have an increasing demand, and their export would be profitable for these farmers. What is, however, most needed for a change is a political will of a government that understands the importance of agricultural and forestry development for poverty reduction.
  • Li, Ning (Finnish Society of Forest Science, Finnish Forest Research Institute, Faculty of Agriculture and Forestry of the University of Helsinki, School of Forest Sciences of the University of Eastern Finland, 2012)
    Growing interest in corporate sustainability has translated into growing concerns about how corporate responsibility management can be more effectively integrated with economic business goals, challenging organizations to shift their priorities toward more holistic strategies and performance assessment models which encompass measures related to both multiple stakeholders and responsibilities. Although interactions between corporate (social) strategy, sustainability performance, and business competitiveness have received considerable attention in both theory and practice over the past three decades, the phenomenon is under-investigated in forest-based industry, which is undergoing broad structural changes and global shifts in market demand and supply. This dissertation aims to fill this gap by approaching it from the resource-based view of the firm and empirically investigating a variety of aspects in an attempt to provide an overview of state-of-the-art corporate sustainability in global forest-based industry and to capture a structured view of the relationships between sustainability performance, competitiveness and economic performance among forest-based companies. The results indicate that both larger and small forest-based companies seem to have clear stakeholder orientations. Driven by legal requirements aspects, small companies tend to adopt informal corporate responsibility strategies and tools to meet their stakeholder expectations. A majority of large forest industry companies appear to have implemented corporate responsibility mainly with a profit-maximizing assumption and a relatively defensive approach parallel to and beyond their core business. To these large companies, environmental and economic issues are dominant in disclosure and profitability, while regional differences are not decisive in formulating strategies for sustainability reporting. Furthermore, the results bolster previous findings that have reported a positive return on corporate responsibility initiatives in terms of profitability, suggesting that corporate responsibility can enhance value creation for forest-based companies. To that end, a differentiated business-oriented approach is necessary in managing the business case for sustainability.
  • Wermundsen, Terhi (2010)
    Knowledge of the habitat requirements of bat species is needed in decision making in land use planning. Bats' hibernation requirements were studied both in Estonia and in southern Finland. In both countries, the northern bat and the brown long-eared bat hibernated in colder and drier locations, whereas Daubenton's bat and Brandt's/whiskered bats hibernated in warmer and more humid locations. In Estonia, the pond bat hibernated in the warmest and most humid conditions, whereas Natterer's bat hibernated in the coldest and driest conditions. Hibernacula were at their coldest in mid-season and became warmer towards the end of the season. The results suggest that bats made an active choice of colder hibernation temperatures at the seasons end. They minimised the negative effects of hibernation early in the hibernation season by hibernating in warmer locations and energy expenditure late in the hibernation season by hibernating in colder locations. The use of foraging habitats was studied in northern and southern Finland. The northern bat used foraging sites opportunistically. Daubenton's bat foraged mainly in water habitats, whereas Brandt's/whiskered bats and the brown long-eared bat foraged mainly in forest habitats. In northern Finland, Daubenton's bats foraged almost exclusively on rivers and typically together with the northern bat. Daubenton's bats and Brandt's/whiskered bats were found only where there were lower ambient light levels. One of the most important things in the management of foraging areas for them is to keep them shady. Hibernacula in Finland typically housed few bats, suggesting that hibernation sites used by even a small number of bats are important. Bats typically used natural stone for hibernation suggesting that natural underground sites in rocks or cliffs or man-made underground sites built using natural stone are important for them. The results suggest that appropriate timing of surveys may vary according to the species and latitude.
  • Niskanen, Anna-Maija (Finnish Society of Forest Science, Finnish Forest Research Institute, Faculty of Agriculture and Forestry of the University of Helsinki, School of Forest Sciences of the University of Eastern Finland, 2013)
    The aim of this study is to assess the clonal variation in Scots pine (Pinus sylvestris L.) clones and in transgenic lines of silver birch (Betula pendula Roth) and its causes, with special attention to the effects of cloning and transgenesis in tree breeding programmes. The parental effect on cloning success variation was studied in an experiment where Scots pine embryogenic lines were initiated from immature seeds of a full diallele cross. The evaluation was made after culture initiation, on maintenance medium and by mature embryo production. Growth and stem straightness of Scots pine clones were assessed in a 10-year field trial established with rooted cuttings. The effect of a single gene transfer, the sugar beet chitinase IV gene (chiIV), was assessed on plant growth, susceptibility to fungal diseases and development of root associated fungal communities and phenology, in a 3-year field trial established with micropropagated transgenic silver birch lines and wild-type clones. The results of the somatic embryogenesis experiment with Scots pine showed that the initiation success, as well as maturation, was more affected by the genotype of the mother than the one of the father, while during the proliferation period the mother s effect decreased and the father s increased. The field trial with Scots pine showed that the tree s genotype, more than the propagation method, has an effect on the plant behaviour in the field. In silver birch transgenic lines, the introduction of a single gene (chiIV) led to a reduction in growth and quality characteristics, although no significant changes occurred regarding fungal disease resistance, ectomycorrhizal colonization or fungal community structure, as compared to the natural variation occurring in wild type clones. The conclusion was that the variation in the success of Scots pine embryogenesis and in the growth of rooted cuttings is strongly affected by genotype and, hence, the rooted cuttings are suitable for testing height growth in breeding programmes. A single chiIV gene transfer did not improve significantly fungal disease resistance in silver birch or interfere with root associated fungal community. However, the variation in adaptive traits among silver birch transgenic lines is at the same level with the variation detected in randomly selected wild-type silver birches and single transgenic lines may be selected in breeding programmes.
  • Chen, Qiuzhen (University of Helsinki, 2016)
    Abstract: In spite of references to agricultural externalities that usually focus more on the negative impacts of agricultural inputs on the environment, the inclusion of preferred benefit externalities on society and the environment has been highlighted in the presence of multifunctional agriculture. When externalities of multifunctional attributes of agriculture are placed in normative contexts, research questions are raised regarding how agricultural externalities in connection to multifunctional agriculture are understood differently in different countries, how different agricultural and agri-environmental policies affect agricultural inputs that crucially contribute to environmentally-negative externalities, and what alternative approach is possible to evaluate agri-environmental externalities, given that no comprehensive monetary assessment for the costs and benefits of externalities currently exists. The objectives of the study are: first to empirically present how agricultural externalities are performed in a multiple-dimensions that include experts perspectives, synthetic assessment levels, and policy impacts examined nationally, regionally and over time; second, to demonstrate a practical understanding in diverse interpretations of agricultural-externality components in different countries in the context of different agricultural, socio-economic, and societal development levels. The study focuses on four specific objectives that have been demonstrated in four articles. More specifically, Article I examines the experts perspectives on agricultural externalities in terms of the perceptions of multifunctional agriculture in China and Finland through cross-table and factor analysis methods based upon surveys with Chinese and Finnish experts, in order to know what different highlights are given in the two countries. Article II illustrates the evolution of policies associated with elements of multifunctional agriculture and rural areas in the past twenty years in China and Finland, and explains reasons for the differences in policy implementation. Article III assesses agri-environmental externalities at the regional level in Finland through a synthetic evaluation method with a relative index that enables the measurement of aggregated effects of several environmental externalities generated by agricultural activities in a concise way. Article IV investigates how measures and payments associated with Finnish Agri-environment Schemes (AESs) performed in N application at different regions. Meanwhile, Finnish policy measures on N use were compared with agricultural policies in China that stress perpetual concern for food security by subsidizing in fertilizers to influence price-ratio of input and output and contribute to high intensity of N use. The different goals of policy and policy measures implemented explained the variation of application rates of fertilizer N both nationally, regionally, and over time. Different perceptions of their profitability, efficiency, and environmental effects implied disparity in N use. This study reveals empirically comparative analysis on agricultural externalities, rather than attempting to build a new theoretical framework for externalities analysis. This thesis contributes to the development of an integrated and comparative structure to review the commonalities and differences in perceptions of agricultural externalities and the impacts of agricultural policies implemented on agricultural input in two countries, and interprets their interrelationships. In addition, this thesis develops a synthetic evaluation approach by using a relative index that stems from the fuzzy logic theory to measure the aggregated effects of several agri-environmental externalities in a concise way. The findings demonstrate that it is essential to have a deeper and practical understanding in different public-policy interference orientations in different countries on the basis of agriculture, environment, and society contexts through a comprehensive empirically comparative study. Key words: agricultural externality, multifunctional agriculture, policy impact, synthetic evaluation, panel data, Finland, China.
  • Sipiläinen , Timo (MTT Taloustutkimus, 2008)
    The objective was to measure productivity growth and its components in Finnish agriculture, especially in dairy farming. The objective was also to compare different methods and models - both parametric (stochastic frontier analysis) and non-parametric (data envelopment analysis) - in estimating the components of productivity growth and the sensitivity of results with respect to different approaches. The parametric approach was also applied in the investigation of various aspects of heterogeneity. A common feature of the first three of five articles is that they concentrate empirically on technical change, technical efficiency change and the scale effect, mainly on the basis of the decompositions of Malmquist productivity index. The last two articles explore an intermediate route between the Fisher and Malmquist productivity indices and develop a detailed but meaningful decomposition for the Fisher index, including also empirical applications. Distance functions play a central role in the decomposition of Malmquist and Fisher productivity indices. Three panel data sets from 1990s have been applied in the study. The common feature of all data used is that they cover the periods before and after Finnish EU accession. Another common feature is that the analysis mainly concentrates on dairy farms or their roughage production systems. Productivity growth on Finnish dairy farms was relatively slow in the 1990s: approximately one percent per year, independent of the method used. Despite considerable annual variation, productivity growth seems to have accelerated towards the end of the period. There was a slowdown in the mid-1990s at the time of EU accession. No clear immediate effects of EU accession with respect to technical efficiency could be observed. Technical change has been the main contributor to productivity growth on dairy farms. However, average technical efficiency often showed a declining trend, meaning that the deviations from the best practice frontier are increasing over time. This suggests different paths of adjustment at the farm level. However, different methods to some extent provide different results, especially for the sub-components of productivity growth. In most analyses on dairy farms the scale effect on productivity growth was minor. A positive scale effect would be important for improving the competitiveness of Finnish agriculture through increasing farm size. This small effect may also be related to the structure of agriculture and to the allocation of investments to specific groups of farms during the research period. The result may also indicate that the utilization of scale economies faces special constraints in Finnish conditions. However, the analysis of a sample of all types of farms suggested a more considerable scale effect than the analysis on dairy farms.
  • Huuskonen, Arto (MTT, 2009)
    The first aim of this thesis was to produce data for evaluating, developing and recommending biologically and economically efficient energy and protein feeding strategies for growing and finishing dairy bulls offered grass silage-based diets. The second aim was to calculate the energy and protein supplies of the dairy bulls fed different grass silage-cereal-based diets and, based on this, to estimate the possible need to revise the current Finnish energy and protein recommendations for growing dairy bulls. The third aim was to demonstrate the phosphorus supply of dairy bulls fed grass silage-cereal-based diets with or without protein supplementation in relation to current feeding recommendations for phosphorus. The results indicate that protein supplement is not needed for finishing dairy bulls (live weight more than 250 kg) when they are fed good-quality grass silage (digestible organic matter more than 650 g/kg dry matter, restricted fermentation with low concentrations of fermentation acids and ammonia N) and grain-based concentrate with a moderate (300-700 g/kg dry matter) concentrate level. The results also suggest that with total mixed ration feeding it is possible to use rather high concentrate proportions (700 g/kg dry matter) in feeding dairy bulls. According to this study, barley fibre is a suitable energy supplement with good-quality silage for growing dairy bulls. The results suggest that 50% of barley grain can be replaced with barley fibre without affecting growth. Also oats is a suitable energy supplement for dairy bulls. However, as a consequence of decreased energy intake, the gain and feed conversion of the bulls were slightly reduced in this study when barley grain was replaced by oats in the diet. Ultimately, the rationality of the use of barley fibre and oats in the future will depend on the price in relation to other concentrates. During the feeding experiments the calculated supply of energy was 10% higher than in the Finnish feeding recommendations for the present growth rate. This indicates that there is a need to update the Finnish feeding recommendations for dairy-breed growing bulls, and further calculations are needed for the energy supply of growing dairy bulls. The calculated supply of AAT (amino acids absorbed from the small intestine) was 38% higher than in the Finnish feeding recommendations for the present growth. Possibly, the present AAT-PBV system is not an optimal protein evaluation system for growing dairy bulls more than 250 kg live weight. The calculations based on the feeding experiments and the Finnish feeding recommendations indicate that in most cases the dairy bulls (live weight more than 250 kg) received enough P from the basic grass silage cereal-based diets without additional mineral feeds. Therefore there is no need to add P in the form of mineral mixtures.
  • Ala-Poikela, Marjo (Helsingin yliopisto, 2014)
    Potyviruses (genus Potyvirus, family Potyviridae) are plant RNA viruses infecting a broad range of agriculturally important crops. Potyviruses have compact genomes encoding a small number of proteins and are therefore dependent on host factors. Even though several host factors are indispensable for plant virus infection, most so far identified natural recessive resistance genes to different potyviruses are homologs of the same genes, translation initiation factor 4E (eIF4E) and its plant-specific isoform eIF(iso)4E. The eIF4E is best known for recruiting ribosomes to capped mRNAs during cap-dependent translation. The viral-genome linked protein (VPg) encoded by potyviruses have been reported to interact with eIF4E/eIF(iso)4E. The hypothesis is that VPg substitutes for the cap-structure by binding to the eIF4E and hereby hijacks and assembles the host cell translation machinery for viral translation that subsequently inhibits host translation. However, the exact roles of eIF4E/eIF(iso)4E in recessive resistance against potyviruses are still cryptic. In this study we present novel data that will give new insights into the molecular mechanisms behind eIF4E-mediated resistance against potyviruses. In this study, we demonstrated that helper component proteinase (HCpro) from Potato virus A (PVA), Potato virus Y (PVY), and Tobacco etch virus (TEV) interacted with the eIF(iso)4E and eIF4E of tobacco (Nicotiana tabacum) and potato (Solanum tuberosum). An eIF4E-binding motif was found in the C-terminal region of HCpro and point mutations within the motif debilitated interactions of HCpro with translation initiation factors and impeded PVA virulence in plants. In PVA-infected cells, interactions between HCpro and eIF(iso)4E were confined to round-shaped structures that associated with the 6 kilodalton protein 2 (6K2)-induced viral replication vesicles. Furthermore an eIF4E-binding motif was recognized in the VPg of PVA and two other potyviruses. Mutations in the eIF4E-binding motif interfered with interactions of VPg with eIF4E, impaired suppression of RNAi by VPg, and abolished virulence of PVA. These results show that the interaction of VPg with eIF4E controlled by the eIF4E-binding motif in VPg is essential for PVA virulence, regardless of that VPg still binds to the cap-binding domain of eIF4E. The capability to bind to two distinct binding sites of eIF4E might reflect two distinct functions of VPg. HCpro and VPg were found to interact with each other in the nucleus and nucleolus in PVA-infected cells. In cytoplasm, the VPg-HCpro interaction was observed in round-shaped bodies in the proximity of the nucleus and chloroplasts, but not in association with the 6K2-induced replication vesicles. The interactions of VPg with eIF4E via the eIF4E-binding domain may also regulate interactions of HCpro with eIF4E. Taken together, the results suggest novel mechanisms by which potyviruses interact with the host translation system and other putative functions involving eIF4E/eIFiso4E.
  • Väre, Minna (Maa- ja elintarviketalouden tutkimuskeskus, 2007)
    In the past decade, the Finnish agricultural sector has undergone rapid structural changes. The number of farms has decreased and the average farm size has increased when the number of farms transferred to new entrants has decreased. Part of the structural change in agriculture is manifested in early retirement programmes. In studying farmers exit behaviour in different countries, institutional differences, incentive programmes and constraints are found to matter. In Finland, farmers early retirement programmes were first introduced in 1974 and, during the last ten years, they have been carried out within the European Union framework for these programmes. The early retirement benefits are farmer specific and de-pend on the level of pension insurance the farmer has paid over his active farming years. In order to predict the future development of the agricultural sector, farmers have been frequently asked about their future plans and their plans for succession. However, the plans the farmers made for succession have been found to be time inconsistent. This study estimates the value of farmers stated succession plans in predicting revealed succession decisions. A stated succession plan exists when a farmer answers in a survey questionnaire that the farm is going to be transferred to a new entrant within a five-year period. The succession is revealed when the farm is transferred to a suc-cessor. Stated and revealed behaviour was estimated as a recursive Binomial Probit Model, which accounts for the censoring of the decision variables and controls for a potential correlation between the two equations. The results suggest that the succession plans, as stated by elderly farmers in the questionnaires, do not provide information that is significant and valuable in predicting true, com-pleted successions. Therefore, farmer exit should be analysed based on observed behaviour rather than on stated plans and intentions. As farm retirement plays a crucial role in determining the characteristics of structural change in agriculture, it is important to establish the factors which determine an exit from farming among eld-erly farmers and how off-farm income and income losses affect their exit choices. In this study, the observed choice of pension scheme by elderly farmers was analysed by a bivariate probit model. Despite some variations in significance and the effects of each factor, the ages of the farmer and spouse, the age and number of potential successors, farm size, income loss when retiring and the location of the farm together with the production line were found to be the most important determi-nants of early retirement and the transfer or closure of farms. Recently, the labour status of the spouse has been found to contribute significantly to individual retirement decisions. In this study, the effect of spousal retirement and economic incentives related to the timing of a farming couple s early retirement decision were analysed with a duration model. The results suggest that an expected pension in particular advances farm transfers. It was found that on farms operated by a couple, both early retirement and farm succession took place more often than on farms operated by a single person. However, the existence of a spouse delayed the timing of early retirement. Farming couples were found to co-ordinate their early retirement decisions when they both exit through agricultural retirement programmes, but such a co-ordination did not exist when one of the spouses retired under other pension schemes. Besides changes in the agricultural structure, the share and amount of off-farm income of a farm family s total income has also increased. In the study, the effect of off-farm income on farmers retirement decisions, in addition to other financial factors, was analysed. The unknown parameters were first estimated by a switching-type multivariate probit model and then by the simulated maxi-mum likelihood (SML) method, controlling for farmer specific fixed effects and serial correlation of the errors. The results suggest that elderly farmers off-farm income is a significant determinant in a farmer s choice to exit and close down the farm. However, off-farm income only has a short term effect on structural changes in agriculture since it does not significantly contribute to the timing of farm successions.
  • Toivonen, Ritva (Suomen Metsätieteellinen Seura ry, 2011)
    The research analyzes product quality from a customer perspective in the case of the wood products industry. Of specific interest is to understand better how environmental quality is perceived from a customer perspective. The empirical material used comprises four data-sets from Finland, Germany and the UK, collected during 1992 2004. The methods consist of a set of quantitative statistical analyses. The results indicate that perceived quality from a customer perspective can be presented using a multidimensional and hierarchical construct with tangible and intangible dimensions, that is common to different markets and products. This applies in the case of wood products but also more generally at least for some other construction materials. For wood products, tangible product quality has two main sub-dimensions: technical quality and appearance. For product intangibles, a few main quality dimensions seem be detectable: Quality of intangibles related to the physical product, such as environmental issues and product-related information, supplier-related characteristics, and service and sales personnel behavior. Environmental quality and information are often perceived as being inter-related. Technical performance and appearance are the most important considerations for customers in the case of wood products. Organizational customers in particular also clearly consider certain intangible quality dimensions to be important, such as service and supplier reliability. The high technical quality may be considered as a license to operate , but product appearance and intangible quality provide potential for differentiation for attracting certain market segments. Intangible quality issues are those where Nordic suppliers underperform in comparison to their Central-European competitors on the important German markets. Environmental quality may not have been used to its full extent to attract customers. One possibility is to increase the availability of the environment-related information, or to develop environment-related product characteristics to also provide some individual benefits. Information technology provides clear potential to facilitate information-based quality improvements, which was clearly recognized by Finnish forest industry already in the early 1990s. The results indeed indicate that wood products markets are segmented with regard to quality demands
  • Lilja, Saara (Helsingin yliopisto, 2006)
    The first aim of this thesis was to explore the structural characteristics of near-natural forests and to quantify how human utilization has changed them. For this, we examined the stand characteristics in Norway spruce Picea abies (L.) Karst-dominated old-growth stands in northwestern Russia and in old Scots pine Pinus sylvestris L.-dominated stands in three regions from southern Finland to northwestern Russia. In the second study, we also compared stands with different degrees of human impact, from near-natural stands and stands selectively cut in the past to managed stands. Secondly, we used an experimental approach to study the short-term effects of different restorative treatments on forest structure and regeneration in managed Picea abies stands in southern Finland. Restorative treatments consisted of a partial cut combined with three levels of coarse woody debris retention, and a fire/no-fire treatment. In addition, we examined burned and unburned reference stands without cutting treatments. Results from near-natural Picea abies forests emphasize the dynamic character of old-growth forests, the variety of late-successional forest structures, and the fact that extended time periods are needed to attain certain late-successional stages with specific structural and habitat attributes, such as large-diameter deciduous trees and a variety of deadwood. The results from old Pinus sylvestris-dominated forests showed that human impact in the form of forest utilization and fire exclusion has strongly modified and reduced the structural complexity of stands. Consequently, small protected forest fragments in Finland may not serve as valid natural reference areas for forest restoration. However, results from the restoration experiment showed that early-successional natural stand characteristics can be restored to structurally impoverished managed Picea abies stands, despite a significant portion of wood volume being harvested. A variety of restoration methods is needed, due to differences in the condition of the forest when restoration is initiated and the variety of successional stages of forest structures after anthropogenic and natural disturbances. Keywords: dead wood, disturbance dynamic, fire, near-natural stand, rehabilitation, succession
  • Favada, Ibrahim (2007)
    This dissertation examines the short- and long-run impacts of timber prices and other factors affecting NIPF owners' timber harvesting and timber stocking decisions. The utility-based Faustmann model provides testable hypotheses of the exogenous variables retained in the timber supply analysis. The timber stock function, derived from a two-period biomass harvesting model, is estimated using a two-step GMM estimator based on balanced panel data from 1983 to 1991. Timber supply functions are estimated using a Tobit model adjusted for heteroscedasticity and nonnormality of errors based on panel data from 1994 to 1998. Results show that if specification analysis of the Tobit model is ignored, inconsistency and biasedness can have a marked effect on parameter estimates. The empirical results show that owner's age is the single most important factor determining timber stock; timber price is the single most important factor in harvesting decision. The results of the timber supply estimations can be interpreted using utility-based Faustmann model of a forest owner who values a growing timber in situ.
  • Nuorteva, Heikki (Finnish Society of Forest Science, 2008)
    A wide range of biotic and abiotic factors, operating over different time perspectives and intensities, cause defoliation and a rapid decrease in the crown size of trees. Scleroderris canker disease [Gremmeniella abietina (Lagerb.) Morelet] has caused widespread crown reduction and tree mortality in Scots pine (Pinus sylvestris L) in forests in Scandinavia during the last three decades. In the 1980's, attempts were made to show, on the basis of the higher foliar N and S concentrations of affected pines in the diseased area, that sulphur and nitrogen deposition predispose trees to G. abietina. Unfortunately, in many studies on defoliated trees, exceptionally high or low needle mineral nutrient concentrations are still often interpreted as one of the causes of tree injury and not, conversely, as the result. In this thesis, three different field experiments, with foliar analysis as the main study method, were conducted in order to asses the possible long-term effects of living crown reduction on the needle nutrient concentrations of Scots pine trees in southern Finland. The crown ratio and length of the living crown were used to estimate the amount of defoliation in the reduced canopies. The material for the partial studies was collected and a total of 968 foliar samples were analysed individually (15-17 elements/sample) on a total of 488 sample trees (140 diseased, 116 pruned and 232 control trees) during the years 1987-1996 in 13 Scots pine stands. All the three experiments of this thesis provided significant evidence that severe, disease-induced defoliation or artificial pruning of the living branches can induce long-lasting nutritional changes in the foliage of the recovering trees under the typical growing conditions for Scots pine. The foliar concentrations of all the 17 mineral nutrients/elements analysed were affected, to a varying degree, by artificial pruning during the following three years. Although Scots pine, as an evergreen conifer, is considered to have low induced chemical responses to defoliation, this study proved experimentally under natural forest conditions that severe artificial pruning or disease-induced defoliation of Scots pine trees may induce biologically significant changes in the concentrations of most of the important macro- and micronutrients, as well as of carbon, in refoliated needles. Concerning the studies in this thesis, I find the results significant in providing new information about the long-term effects of rapid living crown reduction on the foliar nutrient and element status of Scots pine trees. Key words: Foliar analysis, defoliation, needle loss, pruning, nutrients, Pinus sylvestris, Gremmeniella abietina
  • Ylivainio, Kari (2009)
    The low solubility of iron (Fe) depresses plant growth in calcareous soils. In order to improve Fe availability, calcareous soils are treated with synthetic ligands, such as ethylenediaminetetraacetic acid (EDTA) and ethylenediimi-nobis(2-hydroxyphenyl)acetic acid (EDDHA). However, high expenses may hinder their use (EDDHA), and the recalcitrance of EDTA against biodegra-dation may increase the potential of cadmium (Cd) and lead (Pb) leaching. This study evaluated the ability of biodegradable ligands, i.e. different stereo-isomers of ethylenediaminedisuccinic acid (EDDS), to provide Fe for lettuce (Lactuca sativa L.) and ryegrass (Lolium perenne cv. Prego), their effects on uptake of other elements and solubility in soils and their subsequent effects on the activity of oxygen-scavenging enzymes in lettuce. Both EDTA and EDDHA were used as reference ligands. In unlimed and limed quartz sand both FeEDDS(S,S) and a mixture of stereo-isomers of FeEDDS (25% [S,S]-EDDS, 25% [R,R]-EDDS and 50% [S,R]/[R,S]-EDDS), FeEDDS(mix), were as efficient as FeEDTA and FeEDDHA in providing lettuce with Fe. However, in calcareous soils only FeEDDS(mix) was comparable to FeEDDHA when Fe was applied twice a week to mimic drip irrigation. The Fe deficiency increased the manganese (Mn) concentration in lettuce in both acidic and alkaline growth media, whereas Fe chelates depressed it. The same was observed with zinc (Zn) and copper (Cu) in acidic growth media. EDDHA probably affected the hormonal status of lettuce as well and thus depressed the uptake of Zn and Mn even more. The nutrient concentrations of ryegrass were only slightly affected by the Fe availability. After Fe chelate splitting in calcareous soils, EDDS and EDTA increased the solubility of Zn and Cu most, but only the Zn concentration was increased in lettuce. The availability of Fe increased the activity of oxygen-scavenging enzymes (ascorbate peroxidase, guaiacol peroxidase, catalase). The activity of Cu/ZnSOD (Cu/Zn superoxide dismutase) and MnSOD in lettuce leaves followed the concentrations of Zn and Mn. In acidic quartz sand low avail-ability of Fe increased the cobalt (Co) and nickel (Ni) concentrations in let-tuce, but Fe chelates decreased them. EDTA increased the solubility of Cd and Pb in calcareous soils, but not their uptake. The biodegradation of EDDS was not affected by the complexed element, and [S,S]-EDDS was biodegraded within 28 days in calcareous soils. EDDS(mix) was more recalcitrant, and after 56 days of incubation water-soluble elements (Fe, Mn, Zn, Cu, Co, Ni, Cd and Pb) corresponded to 10% of the added EDDS(mix) concentration.
  • Iho, Antti (MTT, 2010)
    Phosphorus is a nutrient needed in crop production. While boosting crop yields it may also accelerate eutrophication in the surface waters receiving the phosphorus runoff. The privately optimal level of phosphorus use is determined by the input and output prices, and the crop response to phosphorus. Socially optimal use also takes into account the impact of phosphorus runoff on water quality. Increased eutrophication decreases the economic value of surface waters by Deteriorating fish stocks, curtailing the potential for recreational activities and by increasing the probabilities of mass algae blooms. In this dissertation, the optimal use of phosphorus is modelled as a dynamic optimization problem. The potentially plant available phosphorus accumulated in soil is treated as a dynamic state variable, the control variable being the annual phosphorus fertilization. For crop response to phosphorus, the state variable is more important than the annual fertilization. The level of this state variable is also a key determinant of the runoff of dissolved, reactive phosphorus. Also the loss of particulate phosphorus due to erosion is considered in the thesis, as well as its mitigation by constructing vegetative buffers. The dynamic model is applied for crop production on clay soils. At the steady state, the analysis focuses on the effects of prices, damage parameterization, discount rate and soil phosphorus carryover capacity on optimal steady state phosphorus use. The economic instruments needed to sustain the social optimum are also analyzed. According to the results the economic incentives should be conditioned on soil phosphorus values directly, rather than on annual phosphorus applications. The results also emphasize the substantial effects the differences in varying discount rates of the farmer and the social planner have on optimal instruments. The thesis analyzes the optimal soil phosphorus paths from its alternative initial levels. It also examines how erosion susceptibility of a parcel affects these optimal paths. The results underline the significance of the prevailing soil phosphorus status on optimal fertilization levels. With very high initial soil phosphorus levels, both the privately and socially optimal phosphorus application levels are close to zero as the state variable is driven towards its steady state. The soil phosphorus processes are slow. Therefore, depleting high phosphorus soils may take decades. The thesis also presents a methodologically interesting phenomenon in problems of maximizing the flow of discounted payoffs. When both the benefits and damages are related to the same state variable, the steady state solution may have an interesting property, under very general conditions: The tail of the payoffs of the privately optimal path as well as the steady state may provide a higher social welfare than the respective tail of the socially optimal path. The result is formalized and an applied to the created framework of optimal phosphorus use.
  • Mattinen, Laura (Helsingfors universitet, 2008)
    The plant pathogen Pectobacterium atrosepticum is a Gram-negative bacterium that causes the diseases soft rot and blackleg in potato. Of the soft rotting bacteria, it has the lowest temperature optimum and it is prevalent in temperate climates. Blackleg spreads mainly through contaminated seed tubers and therefore the disease is a problem especially in the production of seed potatoes. The genome of the P. atrosepticum strain SCRI1043 has been published and it has been studied as a model organism to understand the pathogenesis of soft rot and blackleg. It is an opportunistic pathogen that can live as a biotroph in the host plant for months, without causing symptoms. As the environmental conditions turn favourable, the bacteria start to multiply and produce large amounts of plant cell wall degrading enzymes that macerate the plant tissues. The degraded plant tissue provides nutrients for the bacterial growth and enables colonization of the host. The role of the tissue degrading enzymes in pathogenesis is well known, but the latent phase and beginning of the disease are poorly understood. The genome of the bacterium revealed many putative toxins, adhesins, hemolysins and proteins that might have a function in pathogenesis. In this work, proteomics and microarray analysis were used to study the secreted proteins (secretome) and gene expression of P. atrosepticum. The proteins secreted by the bacterium are likely to have a role in virulence, because they are in direct contact with the host cells. The analyses were performed in conditions resembling plant apoplastic space: low pH, minimal nutrients and low temperature. To reveal the host induced genes and proteins, potato extract was added to the cultivation medium. Many known and putative virulence factors were identified in this study. Potato extracts induced the expression of a recently described secretion pathway, type VI secretion system (T6SS). This conserved system was first described in 2006 and since then it has been the subject of intense scrutiny in many laboratories. In this study, the T6SS of P. atrosepticum was characterized. P. atrosepticum was found to secrete hemolysin-coregulated proteins (Hcp) in a T6SS-dependent manner, and the secretion was dependent on VasK, a putative membrane component of the apparatus. A putative sigma-54 dependent regulator VasH was demonstrated to be a positive regulator of T6SS. Previous evidence indicated that T6SS was a virulence mechanism but the results of this study do not support that hypothesis, since the secretion mutant and regulatory mutant of P. atrosepticum T6SS had increased virulence in the potato maceration assay.
  • Riutta, Terhi (Suomen Metsätieteellinen Seura, Metsäntutkimuslaitos, Helsingin yliopisto Maatalous-metsätieteellinen tiedekunta, Joensuun yliopisto Metsätieteellinen tiedekunta, 2008)
    Northern peatlands are thought to store one third of all soil carbon (C). Besides the C sink function, peatlands are one of the largest natural sources of methane (CH4) to the atmosphere. Climate change may affect the C gas dynamics as well as the labile C pool. Because the peatland C sequestration and CH4 emissions are governed by high water levels, changes in hydrology are seen as the driving factor in peatland ecosystem change. This study aimed to quantify the carbon dioxide (CO2) and CH4 dynamics of a fen ecosystem at different spatial scales: plant community components scale, plant community scale and ecosystem scale, under hydrologically normal and water level drawdown conditions. C gas exchange was measured in two fens in southern Finland applying static chamber and eddy covariance techniques. During hydrologically normal conditions, the ecosystem was a CO2 sink and CH4 source to the atmosphere. Sphagnum mosses and sedges were the most important contributors to the community photosynthesis. The presence of sedges had a major positive impact on CH4 emissions while dwarf shrubs had a slightly attenuating impact. C fluxes varied considerably between the plant communities. Therefore, their proportions determined the ecosystem scale fluxes. An experimental water level drawdown markedly reduced the photosynthesis and respiration of sedges and Sphagnum mosses and benefited shrubs. Consequently, changes were smaller at the ecosystem scale than at the plant group scale. The decrease in photosynthesis and the increase in respiration, mostly peat respiration, made the fen a smaller CO2 sink. CH4 fluxes were significantly lowered, close to zero. The impact of natural droughts was similar to, although more modest than, the impact of the experimental water level drawdown. The results are applicable to the short term impacts of the water level drawdown and to climatic conditions in which droughts become more frequent.
  • Omoro, Loice M A (2012)
    Although forest ecosystems are crucial for human survival they are constantly under threat from human interventions and natural disasters which reduce their capacities to effectively provide ecosystem services. As populations increase, incidences of forest encroachments become frequent to affect the provision of the services. The objective in this study was to assess some ecosystem benefits and to determine how the local communities used and value them. The benefits assessed were floristic diversity; biomass and soil organic carbon densities; and suitability of indigenous tree species for forest rehabilitation based on soil properties in four different forest types, indigenous and plantations of cypress, eucalypt and pine in Taita Hills, Kenya. The perceptions of local community regarding how they use and value these benefits were also assessed. The conceptual framework was based on the Millennium Ecosystem Assessment. Sampling design was based on a US Forest Service model used in the indigenous forests. For each forest area and forest type, a minimum of four plots were randomly selected and a total of 77 plots from 38 groups were sampled. In each plot, all juvenile trees of 5 cm or more in diameter at breast height were sampled for floristic diversity, biomass carbon stock and vegetation-soil relationship assessments. Soils were sampled at, 0-20 and 20-50 cm, for chemical and physical analyses to determine the soil organic carbon densities and vegetation-soil relationships. Tree species diversity, carbon densities derived from biomass and soil data were analyzed quantitatively. A qualitative analysis was done for the socio-economic part of the study, from data obtained using selected participatory rural appraisal tools and semi-structured questionnaires. Biodiversity analyses were accomplished using the Shannon-Weaver s Index. to assess the tree species composition. Tree biomass was estimated from allometric functions developed for tropical forests while soil organic carbon stocks were computed as a product of the analyzed carbon contents and bulk density values estimated using a pedotransfer function and measured particle size. Soil-vegetation relationships were determined by Principal Component Analysis, using CANOCO 4.5 software. The statistical analyses were accomplished by use of three versions of SPSS software for Windows (15, 16 and 20). The study established that indigenous forest was more diverse than plantations and regeneration of indigenous species significantly higher in exotic plantations of the most disturbed area than in the less disturbed areas. Some indigenous species correlated with sodium, phosphorus, carbon, pH and soil texture while some had no correlation with soil variables. Factors unrelated to soil variables, namely gaps were found to be important for the emergence and early establishment of seedlings. Total biomass C densities were generally higher in indigenous forest than in some exotic plantations, especially the cypress. Indigenous forest also had higher soil carbon stocks than plantations of exotic species. Community survey showed perceptions that exotics plantations contributed reductions of the forests to provide water and medicinal plants. Therefore, they are motivated to rehabilitate the forest by planting indigenous tree species. This study concluded that indigenous forest valuable for ecosystem services and that soil-vegetation relationships established be utilized along with soil analyses to select indigenous species to be planted in certain areas for rehabilitation. Such rehabilitation will enhance the floristic diversity and carbon sequestration and storage and therefore, contribute to restoration of the ecosystem services. Therefore, the initiated reforestation exercises with indigenous tree species to replace the exotic tree species are well justified. Key Words: Floristic diversity, biomass, carbon stocks, plantation, indigenous forest, Principal Component Analysis
  • Primmer, Eeva (Finnish Society of Forest Science, Finnish Forest Research Institute, University of Helsinki, and University of Eastern Finland, 2010)
    Integrating biodiversity conservation into forest management in non-industrial private forests requires changes in the practices of those public and private actors that have implementing responsibilities and whose strategic and operational opportunities are at stake. Understanding this kind of context-dependent institutional adaptation requires bridging between two analytical approaches: policy implementation and organizational adaptation, backed up with empirical analysis. The empirical analyses recapitulated in this thesis summary address organizational competences, specialization, professional judgment, and organizational networks. The analyses utilize qualitative and quantitative data from public and private sector organizations as well as associations. The empirical analyses produced stronger signals of policy implementation than of organizational adaptation. The organizations recognized the policy and social demand for integrating biodiversity conservation into forest management and their professionals were in favor of conserving biodiversity. However, conservation was integrated to forest management so tightly that it could be said to be subsumed by mainstream forestry. The organizations had developed some competences for conservation but the competences did not differentiate among the organizations other than illustrating the functional differences between industry, administration and associations. The networks that organizations depended on consisted of traditional forestry actors and peers both in planning policy and at the operational level. The results show that he demand for biodiversity conservation has triggered incremental changes in organizations. They can be considered inert regarding this challenge. Isomorphism is advanced by hierarchical guidance and standardization, and by professional norms. Analytically, this thesis contributes to the understanding of organizational behavior across the public and private sector boundaries. The combination of a policy implementation approach inherent in analysis of public policies in hierarchical administration settings, and organizational adaptation typically applied to private sector organizations, highlights the importance of institutional interpretation. Institutional interpretation serves the understanding of the empirically identified diversions from the basic tenets of the two approaches. Attention to institutions allows identification of the overlap of the traditionally segregated approaches.
  • Bäckman, Stefan (2008)
    The purpose of this study was to evaluate intensity, productivity and efficiency in agriculture in Finland and show implications for N and P fertiliser management. Environmental concerns relating to agricultural production have been and still are focused on arguments about policies that affect agriculture. These policies constrain production while demand for agricultural products such as food, fibre and energy continuously increase. Therefore the importance of increasing productivity is a great challenge to agriculture. Over the last decades producers have experienced several large changes in the production environment such as the policy reform when Finland joined the EU 1995. Other and market changes occurred with the further EU enlargement with neighbouring countries in 2005 and with the decoupling of supports over the 2006-2007 period. Decreasing prices a decreased number of farmers and decreased profitability in agricultural production have resulted from these changes and constraints and of technological development. It is known that the accession to the EU 1995 would herald changes in agriculture. Especially of interest was how the sudden changes in prices of commodities on especially those of cereals, decreased by 60%, would influence agricultural production. The knowledge of properties of the production function increased in importance as a consequence of price changes. A research on the economic instruments to regulate productions was carried out and combined with earlier studies in paper V. In paper I the objective was to compare two different technologies, the conventional farming and the organic farming, determine differences in productivity and technical efficiency. In addition input specific or environmental efficiencies were analysed. The heterogeneity of agricultural soils and its implications were analysed in article II. In study III the determinants of technical inefficiency were analysed. The aspects and possible effects of the instability in policies due to a partial decoupling of production factors and products were studied in paper IV. Consequently connection between technical efficiency based on the turnover and the sales return was analysed in this study. Simple economic instruments such as fertiliser taxes have a direct effect on fertiliser consumption and indirectly increase the value of organic fertilisers. However, fertiliser taxes, do not fully address the N and P management problems adequately and are therefore not suitable for nutrient management improvements in general. Productivity of organic farms is lower on average than conventional farms and the difference increases when looking at selling returns only. The organic sector needs more research and development on productivity. Livestock density in organic farming increases productivity, however, there is an upper limit to livestock densities on organic farms and therefore nutrient on organic farms are also limited. Soil factors affects phosphorous and nitrogen efficiency. Soils like sand and silt have lower input specific overall efficiency for nutrients N and P. Special attention is needed for the management on these soils. Clay soils and soils with moderate clay content have higher efficiency. Soil heterogeneity is cause for an unavoidable inefficiency in agriculture.