Forested peatlands are globally significant carbon pools, important forest resources and areas for other bioproduction. Management of drained peatland forests has partly contradictory targets, such as economic profit, climate change mitigation and adaptation, and water protection. Balancing between these targets by comparing different management options requires a thorough understanding of the ecosystem processes, as well as modelling tools that are able to represent their complexity. This thesis presents three such tools, which are based on process-based models, and their applications to concrete water table management scenarios in drained peatlands.
All three works are built upon a common peat hydrological model. Two of the studies analyze the effect of canal-blocking restoration practices on the water table and carbon dioxide emissions in tropical peatlands. The first work shows that using optimization algorithms to choose the location of a fixed number of canal blocks can lead to sizeable improvements on the amount of peat they rewet. The second work systematically analyzes the impact of canal blocks on tropical peatland water tables, and provides insights about their performance for different weather conditions and peat types. The third study presents a peatland ecosystem model focused on the effect of drainage on nutrient dynamics and forest growth in boreal peatlands. By connecting the relevant hydrological and biogeochemical processes, this ecosystem model enables the study of interconnected phenomena such as the identification of the stand growth limiting factor, and the impact of typical ditch network management operations on the nutrient balance and forest productivity.
In Finland, peatland forests are significant for wood supply, although simultaneously, they are also important for biodiversity, carbon sequestration, water conservation, and recreation. In the 1960s and 1970s, peatland forests in Finland were extensively drained to increase tree growth and fulfil the needs of the forest sector. However, this extensive drainage has negatively impacted on the biodiversity of peatland ecosystems, and substantially increased nutrient and sediment emissions to lakes and rivers resulting in eutrophication, turbidity, and brownification of these water bodies.
This dissertation presents a number of approaches to move peatland forest management in a more environmentally sound direction, which may increase the general acceptability of peatland forestry. Airborne LiDAR (Light detection and ranging, i.e., laser scanning) derived 3D point cloud provides useful data, for example, to estimate forest biomass, to identify low-productive peatland forests, to model overland water flows, and to identify wet areas. The strength of airborne LiDAR is the ability of laser pulses to pass through tree canopies and obtain accurate observations from the ground level. The information derived from airborne LiDAR can enhance the planning of peatland forest management, as much of the planning can be done remotely, and supplementary field work can be implemented in areas of strategic need.
This study presented the novel idea of applying local binary patterns for the prediction of terrain trafficability, which should be considered in further studies and practice. The moisture index derived from the local neighborhood can reveal the small-scale variations in terrain moisture. This study also presented the novel idea to create spatial models to identify suitable locations for water protection structures, which may help forest managers to plan water protection of ditch network maintenance or peatland restoration operations. Overall, the utilization of airborne LiDAR-derived information for the development of peatland forestry practices shows great potential.
For the past 25 years, the Finnish state has supported the diffusion of wooden multistory construction into the construction sector. Given the socio-cultural and economic value of Finland’s forest sector, there is precedent to do so. Nonetheless, wooden multistory construction remains a niche construction practice in its formative phase. This dissertation researches the diffusion of wooden multistory construction by analyzing perceptions from municipal civil servants tasked with overseeing land use planning in Finland. Despite being gatekeepers of local construction activities, their perceptions towards wooden multistory construction are understudied. To access these perceptions, this research applies the theory of planned behavior. At the root of this theory lies the notion that beliefs underpin human action. Specifically, this dissertation research identifies (Article I) and operationalizes (Article II-III) the attitudes and beliefs that municipal civil servants hold towards wooden multistory construction. The results are distilled into three empirical accounts. Why not wood? (Article I) reframes elicited beliefs as barriers and benefits to wooden multistory construction. Benefits include a variety of holistic topics ranging from improving the lifestyles of citizens and supporting local wood-based businesses, to facilitating aspects of building construction. On the other hand, multiple barriers coalesce to form a risky and costly environment that results in project aversion. Wood versus concrete (Article II) analyzes how outcomes of implementing wooden multistory buildings are relativized against concrete multistory buildings. In large part, wooden multistory buildings are believed to possess several superior qualities (e.g., environmental performance, economic development outcomes). Nevertheless, apprehensions persist (e.g., they are more expensive to build and maintain, they are more susceptible to fire). Background experiences, especially occupational profession, play a key role in shaping several beliefs. Planning for wood (Article III) studies the relationship between how beliefs (i.e., environmental performance, economic development, cost-related attributes, technical qualities) form attitudes towards wooden multistory buildings. The prioritizations of beliefs vary according to occupational profession. Planning practitioners form attitudes holistically, based on the building’s environmental performance, technical qualities, and economic development outcomes. Other administrators form attitudes primarily based on the project’s economic development outcomes and technical qualities. Ultimately, municipal civil servants appear receptive towards implementing wooden multistory buildings in their municipalities, but this receptiveness hinges on project outcomes and the “societal goods” prioritized by the individual respondent. Even if wooden multistory buildings are perceived to possess superior qualities (e.g., environmental performance), these qualities may not strongly impact an individual’s attitude towards favoring the project. Different prioritizations among municipal civil servants might lead to planning tensions within the municipal administration, but it remains to be seen how these tensions enable (or hinder) wooden multistory construction diffusion.
The utilization of forest side-streams is associated with the applied bioenergy technology that must be impellent to support the increasing demand for biofuels and resources while lowering greenhouse gas (GHG) emission from the transport sector. This study aimed to estimate potential biofuel production from eutrophic (EL) and mesotrophic (ML) lake bottom biomass and the manufacturing side-streams from the pulp and paper mill (PI – PVIII). Theoretical biogas and bioethanol productions were modeled by Aspen Plus® simulation through 1) saccharification and fermentation, 2) gasification and mixed alcohol synthesis, 3) gasification-syngas fermentation, and (4) anaerobic digestion processes. In addition, the different process stages of the pulp and paper side-streams was studied by ABE fermentation using Clostridium acetobutylicum DSM 1731.
The bioethanol produced from EL and ML biomass from indirect gasification and mixed alcohol synthesis were 244.5 L/t and 57.1 L/t, whereas the yields from saccharification and fermentation were 137 L/t and 40 L/t, respectively. The EL biomass produced the most profitable bioethanol production from the latter process. The ML and EL biomass produced biogas of 38.9 mL/g volatile solid and 136.6 mL/g volatile solid, respectively. The ash from the EL and ML biomass and the dried samples of PI and PIII could be used as fertilizer because the harmful elements for Finnish fertilizer products were below the detectable limit. The primary sludge (PII) sample had found high N and P concentrations and cadmium (Cd) concentration (3 mg/kg), which exceeded the Cd limit for Finnish fertilizer products (1.5 mg/kg). However, wet primary sludge (PII) forming 300,000 tonnes/year (72600 dry tonnes) produced anhydrous ethanol about 3011 kg/h (24,090 tonnes/year) when PII was used for the gasification-syngas fermentation process in the bioethanol plant model.
Three pulp and paper side-streams (PI, PII and PIII) with unwashing and water washing were pretreated with dilute acid (0.2% H2SO4 at 180 °C for 10 min), followed by saccharification and ABE fermentation. The results suggested that water washing did not affect the PII and PIII prehydrolysate sugar recovery, as well as enzyme hydrolysis of the rejects from kraft pulping (PI) did not require prewashing before dilute acid pretreatment. In addition, the unwashed PI side-stream yielded the highest ABE concentration of 12.8 g/L, compared to the unwashed PII and PIII side-streams, 5.2 g/L, and 6.3 g/L, respectively. The side-streams from different process stages in pulp and paper mill were concluded to be high potential feedstocks for biofuels production due to their chemical compositions. The unwashed PI was suitable feedstock for butanol production, while PII could be fully utilized in the integrated gasification-syngas fermentation process. Primary sludge (PII) was found to be a promising feedstock for bioethanol and an internal rate of return (IRR) of 15 % can be obtained by two implementations. One was a cost-competitive ethanol selling price (ESP) of €0.61–0.71/L with an ethanol subsidy of €150/t at different tax rates, and the other was an ESP of €0.60–0.70/L with the imposition of a €20/t gate fee. In the future, the addition of an integrated biofuel production operations unit, installed close to a pulp and paper mill, could utilize the different pulp side-streams and create further revenues to the mill owners.
Establishing protected areas and maintaining biodiversity in managed forests are the main methods to conserve forest habitats and their biodiversity. The habitat characteristics that affect forest biodiversity in both protected and managed forests occur on different spatial scales, with the smallest scale consisting of structures at the level of single trees and smaller. Under the influence of dynamic processes (ecological succession, natural and anthropogenic disturbances) small-scale structures may be strongly affected, altering their contribution to local biodiversity.
In this thesis, I studied two small-scale structures in northern boreal forests: deciduous trees (mainly European aspen (Populus tremula)) in conifer-dominated forests and woodpecker-made breeding cavities. These structures provide resources for multiple species. However, their abundance could be affected by dynamic processes, also in protected areas. I examined the temporal dynamics of these structures through long-term (16–30 years) monitoring. Specifically, I studied the recruitment of deciduous trees in managed forests, aspen demography in old-growth forests, the effect of tree- and stand-level factors on cavity persistence, and the potential to detect aspen for conservation purposes via remote sensing.
My main findings were:
1) Recruitment of deciduous trees is enhanced by prescribed burning. Mammalian herbivory impacts recruitment significantly, although its effect depends on forest age.
2) Living aspens declined by 37% in protected old-growth forests over an 18-year period and recruitment rate was low despite an abundance of saplings. Recruitment primarily occurred on forest edges.
3) Tree species, size, and condition affect the persistence of woodpecker-made cavities, with cavities lasting longer in coniferous, healthy, and larger trees. For aspen, cavities in small trees also persisted a long time.
4) Multispectral drone images can be used to detect scattered mature aspen trees in old-growth forests, most ideally in late spring.
My results emphasize that dynamic processes in forests can alter forest characteristics that are important for biodiversity quickly. Small-scale structures, that are essential to maintain local biodiversity, underwent strong changes in just a few decades. My thesis highlights the importance of continuous monitoring of biodiversity-rich habitat structures to uncover major changes in the ability of protected areas to sustain biodiversity. Remote sensing is potentially a valuable monitoring tool, also for tree-level small-scale forest structures.
This study analyzes the political legitimacy of forest and forest-related nature conservation policies in Finland. Legitimacy is defined here that the forest and nature conservation regimes and related political institutions are perceived as rightful among the people.
The major contribution of this study is the comprehensive conceptual framework of legitimacy based on several theories, mainly from political science. The framework analyzes the objects of support, patterns of legitimacy, performance evaluations, and how these relate to one another. In this study, the objects of support refer to forest-related political institutions; these include regulations and public incentives, as well as decision-making processes, political programs, and administrative procedures. The framework is intended to be especially useful in the empirical analyses of pluralistic public political discussion and uses a methodology developed for this purpose. The study also analyses the social values of organized political actors.
The empirical part of this study explores a data set from Finnish print media discourse, based on letters to editors in three newspapers and in one journal, along with comments given during the preparation of Finland's National Forest Programme 2010. Another empirical data set consists of qualitative semi-structured interviews and the writings of the organized interest groups.
Many different groups of citizens were found to participate in public discussion on forests. Quite a large number of individuals shared the overall publicity, despite the fact that there were some very active writers. Nature conservation organizations, researchers, and politicians were well represented. However, the participation of governmental officials from both the forest and environmental sectors can be characterized as insufficient, considering their importance in the implementation of policies.
The study of letters to editors found that groups of common social values served as patterns of legitimacy in the performance evaluations of forest policies. These include welfare and wellbeing derived from forests; values related to nature conservation; democratic values; distributive justice; good governance; core regime principles; and fair markets. Of all performance evaluations, 52% were negative while 26% were positive and 22 % were mixed.
The welfare of citizens and the nation, export incomes and employment were the most common justifications used in the legitimacy evaluations while economic growth was a topic that divided opinions. Principles related to values of nature and sustainable development were almost as common in the data. A common argument related to the wellbeing of future generations combined the ideas of benefits and nature values with the idea of distributive justice.
Democratic values, especially the public participation of the involved groups of people and public deliberation were common sources of legitimacy. Most political actors supported the ideal of conciliatory decision-making, while smaller group preferred strictness and non-compromising political action.
Private property rights and the so-called everyman's right were found to be strong supporting arguments. In addition to the recognition of private ownership of forests, they were on the other hand perceived as national heritage. The perceived fairness of the distribution of benefits and burdens was mostly based on comparisons between people or groups of people; these include countryside vs. cities, Finland vs. foreign countries, forestry vs. other forest user groups, and present vs. future generations.
Both forest and nature conservation-related public administration faced positive and negative feedback. Public officials were expected to obey domestic and international legislation and to oversee the implementation of laws in an impartial and consistent manner. On the contrary, perceived arbitrariness, paternalism, and disrespectful behavior by officials were perceived as illegitimate.
Concerning the markets, the rules of fair competition were often mentioned as a source of legitimacy, while monopolies and cartels were mentioned as sources of illegitimacy.
In the interviews of organized actors, the forestry actors maintained that the central sources of legitimacy are the benefits for the national economy, employment and export incomes, as well as property rights and the value of nature in terms of its benefit for humans while the nature conservation-oriented actors had an understanding that nature has an intrinsic value independent of its benefits to people. Lack of trust was characteristic of the polarized policy field. However, traditional rights of ownership, everyman's right, and citizens’ rights to influence forest policy comprised a common ground between the actors.
Domestic, EU-level, and international legality were commonly perceived as sources of the legitimacy of policies. Finland's good international standing and its role as a moral and economic forerunner were very common principles in the evaluations in both the forest and nature conservation policies, in all parts of data. The same idea was also found central in the national forest programs and strategies. The shared goal of the Finns seems to be that the nation would be best in the world both in forest and nature conservation policies.
Despite some disagreements concerning the performance of institutions, most of the social values that serve as a basis of legitimacy seem to be quite commonly supported in Finland, where support of major governmental institutions and general trust among people are at a relatively high level. The value discussion related to forests is part of a larger discussion on social values that seems to continue far into the future.
The aim of this thesis was to test the possibility of using the residues and side-streams from Finnish wood and coffee industries as active ingredients in wood preservative formulations, as well as to compare their acute ecotoxicity. Pyrolysis distillates of bark from Norway spruce (Picea abies (L.) H. Karst.), silver birch (Betula pendula Roth) and European aspen (Populus tremula L.), the organic acids identified in these distillates, spent coffee extract, coffee silverskin extract, caffeine and the commercial Colatan GT10 tannin-rich extract were tested. Celcure C4 industrial copper preservative (for above ground use) and pine oil were used as industrial references. Antifungal tests against wood-decaying fungi and wood decay—mini block—tests were performed in vitro, and leaching tests of the potential preservatives from wood were performed. An acute ecotoxicity test with Aliivibrio fischeri photoluminescent bacteria was performed in order to compare the ecotoxicity of the potential bio-based preservatives with that of the industrial reference.
All potential bio-based preservatives showed some activity against the fungi in the antifungal tests. The minimum inhibitory concentration of the extracts from coffee industry residues needed to inhibit completely all the wood-decaying fungi was over 1%. The pyrolysis distillates were able to inhibit most fungi at concentrations close to 1%. The organic acids and caffeine were able to inhibit wood-decaying fungi in the malt agar media at concentrations below 1%, showing that these constituents play a significant role in the antifungal activity of the tested distillates and extracts. However, when the potential bio-based preservatives and their constituents were tested in the wood decay tests, none of them performed efficiently as wood preservatives.
The acute ecotoxicity test showed that most of the potential bio-based preservatives had low ecotoxicity, but one of the distillates exhibited IC20 of 0.02 mg/L and IC50 of 0.2 mg/L, a much higher ecotoxicity than Celcure C4, which had IC20 and IC50 values of 12 mg/L and 19 mg/L respectively. This shows that we must test the ecotoxicity of all potential antifungals before proposing them as possible wood preservatives, to ensure that new solutions are not as harmful to the environment as the present ones. It can be concluded that some of the constituents of the potential bio-based preservatives act as antifungals against wood-decaying fungi and could be included in wood preservative formulations, but their performance alone is insufficient to function as wood preservatives.
Soil erosion processes are common in Mediterranean areas due to its climatic conditions, abrupt topography, and its long history of human influence and intensive land management. Forests have a fundamental protective role in combatting soil erosion and land degradation. This research focused on i) assessing soil erosion on forest lands linked to forest variables, and ii) integrating erosion risk into forest management and planning. In more detail, the first goal focused on the relation between erosion occurrence and possible influencing factors such as forest structure and composition, site and land-use characteristics, and, based on this, integrating erosion protection as an objective into multi-functional forest management. The data source was the Spanish National Forest Inventory, which provided erosion records as well as traditional tree and plot measurements. The modelling methods used included classification trees and binary logistic regression analysis. Models were developed for the stand and landscape levels to predict the probability of erosion. Erosion risk was also studied spatially by producing maps based on the predictions of the models. Finally, the models were integrated into a simulation optimisation system in order to assess management alternatives.
The results show that, at the stand level, a higher probability of surface erosion occurrence was strongly related to the forest type and stand structure. For example, sparse stands on slopes in semiarid areas and dense stands with large trees in pure Abies alba and Facus sylvatica forest had higher erosion probability. At the landscape level, a low stand basal area, andisol and cambisol soil types, large size and steep slope of the drainage area, the presence of unpaved roads and increased urban land use resulted in a higher probability of gully erosion. Based on the developed models, erosion protection was used as the management objective in multi-functional forest planning at the stand level, together with timber production and structural diversity. The results demonstrated evident trade-offs between these ecosystem services, depending on the steepness of the slope. The results of this work can help to identify forest areas vulnerable to soil erosion. It provides tools to integrate erosion risk into forest planning, thus enhancing the use of forests in erosion protection in sensitive Mediterranean areas.
Cultural Factors of Environmental Disputes in Lapland studies the cultural meanings of Lapland’s nature and its use. The focus is on the shared meanings and practices of local people and natural resource management. Social and cultural sustainability, as well as conflict management, are the basic concepts and themes permeating this academic dissertation, which is based on several case studies. The geographical focus of study is in the home district of the Saami people in Upper Lapland, but is not strictly limited to this area.
The thesis consists of seven separate articles published in domestic and foreign scientific publications. The theoretical framework for the articles is anchored in the management of natural resources and environmental disputes, as well as the theories of shared cultural meanings. The data was gathered through surveys and interviews – thus the materials and methods of analysis are quantitative and qualitative. The research belongs to the field of socio-scientific environmental research.
The main findings of the study stress that environmental disputes and their management in Lapland are characterised by the diversity of stakeholders that often do not share the same views. The roles and motivations of the stakeholders in environmental conflict situations are often unclear or problematic, and often no shared understanding of the nature, causes and possible consequences of the dispute can be reached. For governmental natural resource management, there has been a lack of institutional structures and processes which are culturally sensitive and socially sustainable. However, new and better practices have been introduced in recent years.
In Lapland, the importance and appreciation of traditional livelihoods such as reindeer herding and subsistence-use of natural resources are emphasised. However, the cultural meanings of these land-use patterns are not adequately recognised. This thesis argues that more cultural sensitive approaches are needed in resource and environmental conflict management. In Upper Lapland, which has undergone rapid cultural transformation, the past is strongly present and explains the valuations and meanings of local people’s use of nature. Nature conservation is, in particular, an important form of land use in upper Lapland. Successful and sustainable conservation should use transparent and culturally novel approaches to achieve the approval and support of the local population. In the future, nature conservation projects will be in favour of exploiting cultural information related to nature and its use, together with ecological knowledge, so that projects receive positive reception.
This study employed scenario analyses to evaluate the effects of forest management and different CMIP5 climate projections on timber production and carbon stocks of upland boreal forests in Finland. The forest ecosystem model simulations were conducted over a 90-year period from the stand to regional level by using both model stand data (Paper I) and national forest inventory data (Papers II-III). In simulations, it was employed data from the current climate and several CMIP5 projections (multi-model means and selected climate model runs of 28 global climate models) under the RCP4.5 and RCP8.5 forcing scenarios. More specifically, it was studied the impacts of different climate projections and thinning regimes (Papers I and III), tree species preferences in forest regeneration (Paper II) and forest conservation scenarios (Paper III) on volume growth, carbon stocks and timber production (Papers I-III), economic profitability (Paper I), and the amount of deadwood of forests (Paper III).
The effects of different climate projections on volume growth, carbon stocks, timber production and its economic profitability and the amount of deadwood varied largely, depending on geographical region, tree species, and severity of climate change. The degree of differences in the responses of tree species and boreal regions increased with the severity of climate change. Regardless of the tree species, the positive impacts of climate change were larger in the north. In the south, Silver birch benefitted most from the climate change projections and the most under severe climate change. This was unlike Norway spruce and also partially, Scots pine. An increase in forest conservation area increased volume growth, carbon stock, and the amount of deadwood in forests, unlike timber production. Depending on boreal region, tree species, and severity of climate change, different adaptive forest management measures would be needed to utilize the positive impacts of climate change and to minimize harmful ones.
Tropical peatlands of South East Asia are major hotspots of biodiversity and great carbon stores. The main peat forming ecosystem is tropical peat swamp forest (TPSF) growing on top of meters deep peat. Forest degradation by vast scale land conversions and consequent pernicious impacts on the environment have raised an urgent need for conservation and restoration. This dissertation concentrates firstly on the peat soil properties, ground surface microtopograhy and vegetation patterns of the natural TPSF, and secondly on the vegetation restoration, i.e. reforestation of degraded tropical peatland.
In the studied natural TPSF type, the forest floor can be characterized as an irregular continuum of less common hummocks and more abundant flat low-lying surface where most of the peat surface is not inundated for most of the year. Unlike in the boreal and temperate peatlands, the ground surface microtopography had no regular patterning. The surface peat structure and chemistry had differences in relation to the surface microtopography. Higher surfaces had higher nutrient concentrations and saplings and trees were concentrated on higher surfaces whereas seedlings emerge in all ground surface elevations.
In the open degraded former TPSF area we tested 21 native tree species for their potential for reforestation in a planting experiment. We increased the knowledge on the species’ early stages flood and drought tolerances, species’ suitability for different conditions in reforestation areas and suitable species-specific seedling height for planting. For five species with known potential for reforestation purposes we tested the impact of three site preparation treatments, weeding, fertilizing and mounding, on the seedling performance. We analyzed also the effects of wildfires which caught the study area two years after planting.
With increased knowledge on both natural TPSF ecology and the seedling experiments on degraded areas, we could specify environmental condition requirements for several tree species for reforestation.
In this study, the effects of restoration of forestry-drained peatlands on the nutrient and organic carbon exports and methane dynamics of the restored sites are explored. The study consists of four sub-studies. Two of the sub-studies are concerned with the effects on water quality and export of elements of restoration and were conducted on a catchment scale. One of the studies was conducted in the laboratory, and assessed the release of elements from peat samples under anaerobic inundation simulating the effects of a rising water table after restoration or logging. The fourth study was again a field study, in which the differences in methane emissions between undrained, drained and restored spruce swamp forests were assessed. In all, 24 different pristine, drained and restored sites are featured in the study, one site being present in two of the sub-studies.
The results indicate potentially large effects of restoration especially on the nutrient rich spruce-dominated sites, which had the highest restoration-induced increases in organic carbon and nutrient exports in the catchment studies, and which also exhibited high methane emissions after restoration, higher than in the undrained or drained state. The results should prompt research into the techniques applied in restoration of such sites and into the processes which lie behind these large effects.
In this study, 1) a model to estimate soil carbon dioxide (CO2) balance for forestry-drained peatlands was tested on site and countrywide levels in Finland. 2) A dataset of annual soil–atmosphere fluxes of CO2, methane (CH4) and nitrous oxide (N2O) from 68 sites was collected, and models fitted for their upscaling to a countrywide level. 3) The current greenhouse gas impact of the 68 study sites, including soil CO2, CH4 and N2O balances and the CO2 sink function of tree biomass increment, was estimated.
The soil CO2 balance estimation, as the difference between litter input to soil and CO2 efflux from soil, was straightforward to apply, but considerable uncertainty was caused by the inadequate level of knowledge on belowground plant–soil carbon fluxes. Soil–atmosphere gas fluxes could be upscaled to a countrywide level utilizing readily available forest inventory results and weather statistics. Soils in nutrient-rich study sites were sources of greenhouse gases while those in nutrient-poor study sites were sinks, on average. The current greenhouse gas impact, when no forest fellings occurred, was nevertheless climate cooling for both the nutrient-rich and poor sites due to the considerable CO2 sink formed by increasing tree biomass.
The aim of the study was to investigate the effects of climate change on soil hydrology and carbon (C) fluxes in boreal peatland ecosystems, with implications for the feasibility of cultivating reed canary grass (Phalaris arundinacea, L; RCG) as a way to restore the C sink in cutaway peatlands under Finnish conditions. First, hydrological models were developed for pristine peatland ecosystems and the cutaway peatlands under RCG cultivation. Concurrently, the hydrological responses to varying climatic forcing and mire types were investigated for these ecosystems. Thereafter, process-based models for estimating the seasonal and annual C exchanges were developed for the pristine mires and cutaway peatlands. The C models incorporated the hydrological models for corresponding ecosystems. Model simulations based on the climate scenarios (ACCLIM, developed by the Finnish Meteorological Institute, FMI) were further carried out to study the impacts of climate change on the C exchanges in the peatland ecosystems during the 21st century.
The simulation showed that the water table (WT) in the pristine Finnish mires would draw down slightly during the 21st century. Such a change in WT would be related to a decrease in the CO2 sink but an increase in the CH4 source at the country scale, as driven mainly by the rising temperature (Ta) and increasing precipitation (P). These changes in CO2 / CH4 fluxes would decrease the total C-greenhouse gas (GHG) sink (CO2 equilibrium) by 68% at the country scale, and the changes would be more pronounced toward the end of the century. The majority of pristine fens in southern and western Finland and the pristine bogs near the coastal areas would become centurial CO2 sources under the changing climate. On the other hand, the major distribution of fens in northern Finland would act to increase the CH4 source at the country scale, whereas the CH4 emission would tend to decrease with WT in the southern and western areas of Finland. Peat extraction and RCG cultivation tends to limit the influence of WT on the root-zone moisture content in a peatland ecosystem, resulting in a high sensitivity of soil moisture content to the regularity of summer rainfall. However, the phenological cycle of RCG may represent an adaptive feature of photosynthesis to the stochasticity of summer precipitation. By the end of the 21st century, climate change will decrease the CO2 sequestration by 63% - 87% in a cutaway RCG peatland during a main rotation period of 12 years. Nevertheless, the site could sustain a net CO2 sink, which is comparable to the pristine peatlands in the same region.
Europe was declared malaria free in 1975. The disappearance of malaria has traditionally been attributed to numerous deliberate actions like vector control, the screening of houses, more efficient medication etc. Malaria, however, disappeared from many countries like Finland before any counter measures had even started. The aim of this thesis is to study the population ecology of P. vivax and its interaction with the human host and the vector. By finding the factors that attributed to the extinction of vivax malaria it might be possible to improve the modern strategy against P. vivax. The parasite was studied with data from Finland, which provides the longest time series (1749-2008) of malaria statistics in the world. The malaria vectors, Anopheles messeae and A. beklemishevi are still common species in the country. The eradication of vivax malaria is difficult because the parasite has a dormant stage that can cause a relapse long after a primary infection. It was now shown that P. vivax is able to detect the presence of a potential vector. A dormant stage is triggered even from a bite of an uninfected Anopheles mosquito.
This optimizes the chances for the Plasmodium to reach a mosquito vector for sexual reproduction. The longevity of the dormant stage could be shown to be at least nine years.
The parasite spends several years in its human host and the behaviour of the human carrier had a profound impact on the decline of the disease in Finland. Malaria spring epidemics could be explained by a previous warm summer. Neither annual nor summer mean temperature had any impact on the long term malaria trend. Malaria disappeared slowly from Finland without mosquito control. The sociological change from extended families to nuclear families led to decreased household size. The decreased household size correlated strongly with the decline of malaria. That led to an increased isolation of the subpopulations of P. vivax. Their habitat consisted of the bedrooms in which human carriers slept together with the overwintering vectors. The isolation of the parasite ultimately led to the extinction of vivax malaria. Metapopulation models adapted to local conditions should therefore be implemented as a tool for settlement planning and socio-economic development and become an integrated part of the fight against malaria.