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Peatlands are important ecosystems that provide ecohydrological functions related to carbon storage and cycling, water quality, flood attenuation, and groundwater recharge. One key characteristic that gives peatlands these functions is the capacity to swell and shrink upon wetting and drying, commonly referred to as peat volume change. This property of peat volume change is closely related to the fluctuations of the water table and has a buffering effect on the water table depth relative to the peat surface, which acts as an important control on many ecohydrological functions such as carbon cycling, vegetation composition, and biogeochemical processes. In an attempt to fill a gap of knowledge, this thesis investigated peat volume change for multiple Northern peatlands close to Umeå, Sweden, using groundwater level and mire surface level data obtained during the summer of 2021. The objectives were to investigate the temporal trends and characteristics of changes in the water table and peat volume at the studied site and to determine how peat volume change capacity differs for mires of different ages, as well as different land management such as natural, drained and restored peatlands. It was found that old (older than 2000 years) mires have a significantly smaller peat volume change capacity compared to young mires (younger than 1000 years), as well as smaller specific storage, indicating that factors that change as the peatland evolves are important for the ability to expand and contract. It was also found that the relationship between the mire surface and water level was linear for some mires but not for others, including drained and old mires. For the drained mires this could be explained by very deep water tables compared to the natural mires, however, they did not stand out among the natural mires concerning peat volume change capacity. The comparison between a restored mire and a drained gave ambiguous results. It was also found that the specific storage, which is directly related tothe compressibility of the peat, was greater during drying conditions compared to rewetting conditions, highlighting peatlands ability to maintain wet conditions. The study provides a deeper understanding of peat volume change in Northern peatlands and the factors related to this phenomenon, which is crucial for further studying of peatland ecohydrology. / Torvmarker är viktiga ekosystem som bidrar med ekohydrologiska funktioner relaterade till kollagring och kolcykling, vattenkvalitet, minskad översvämningsrisk och grundvattenbildning. En egenskap hos torv som är viktig för dessa funktioner är förmågan att svälla under våta perioder och krympa under torrperioder. Denna torvvolymförändring är relaterad till fluktuationer i grundvattennivå och kan även ha en buffrande effekt på grundvattendjupet (avståndet från markytan till grundvattenytan), vilket påverkar flertalet ekohydrologiska funktioner såsom kolcykling, vegetationssammansättning, och biogeokemiska processer. I ett försök att fylla en lucka i kunskapen kring detta fenomen undersökte detta examensarbete torvvolymförändringar för flera torvmarker, eller myrar, i närheten av Umeå baserat data för grundvattennivåer och nivån på myrars markyta som erhållits under sommaren 2021. Syftet var identifiera trender och egenskaper hos de olika myrarnas förändring i grundvattennivån och myrnivå, samt att ta reda om det finns någon skillnad i torvens kapacitet för att svälla och krypa hos myrar med olika ålder, samt olika markskötsel såsom naturliga, dränerade och restaurerade myrar. Resultatet visade att äldre (äldre än 2000 år) myrar har en betydligt mindre kapacitet att svälla och krympa jämfört med yngre myrar (yngre än 1000 år), samt mindre specifik magasinkoefficient, vilket indikerar att faktorer som förändras när myren blir äldre är viktiga för förmågan att svälla och krympa. Resultatet visade också att förhållandet mellan myrens marknivå och grundvattennivå var linjärt för vissa myrar men inte för andra, inklusive dränerade och gamla myrar. För de dränerade myrarna kunde detta förklaras av mycket djupa grundvattennivåer jämfört med de naturliga myrarna, men de stack inte ut bland de naturliga myrarna vad gäller förmåga att svälla och krympa. Jämförelsen mellan en restaurerad myr och en dränerad gav tvetydiga resultat. Man fann också att den specifika magasinkoefficienten, som är direkt relaterad till torvens kompressabilitet, var större under torra perioder jämfört med våta perioder, vilket visar på myrens förmåga att upprätthålla våta förhållanden. Studien gav en djupare förståelse för myrars förmåga att svälla och krympa och faktorerna relaterade till detta fenomen, vilket är av betydelse för vidare forskning om torvmarkers ekohydrologi.

The chemical company Perstorp AB has a 50 MWth circulating fluidized bed to supply the production plant with process steam. The fuel mixture used shows a large variation with about 20 different fuel fractions that can be divided into the categories, residue wood chips, sludge, forest fuel, animal waste, industrial residues, and peat. From an economic and environmental perspective, the use of peat should be minimized because it is classified as a fossil fuel. Peat has positive combustion characteristics due to a combination of sulfur and silica based minerals that can reduce alkali chloride related corrosion. Therefore it is not always possible phase out peat without negatively affecting the boilers availability. Besides reducing CO2 emissions, it is desirable to reduce the use of additives such as limestone and to use cheap waste fractions as fuels when operating a boiler. Similar to peat, reduced use of limestone and the introduction of a new waste fractions can affect the boiler availability negatively. If less limestone is used the risk of agglomeration can increase and often waste products can contain ash elements problematic in both a agglomeration and corrosion perspective.The aim of this master thesis is to investigate the possibility of reducing the usage of peat by minimizing the limestone content and to see if it would be possible to add a new Na-rich waste fraction to the fuel mixture. This was investigated by determining first what fuels that are used and in what amounts. Each fuel was either sent for new elemental analysis or existing analyses were used depending on if it was deemed to be still representative. With the help of experienced personnel working with the boiler, future possible cases for fuel mixtures could be determined: Case 1. Replacing peat with forest fuels. Case 2. Replacing peat with residue wood chips. Case 3. Replacing both peat and animal waste with residue wood chips. Case 4. Introducing Na-rich fuel. The theoretical available SO2 content could be determined for each case and three limestone levels. For each case the CO2 emissions and the economic savings could be estimated when the peat were fully removed and the limestone content halved. From an SO2 perspective, the results indicate that it could be possible to phase out peat for cases 1-2 by adjusting the limestone levels but this would not be enough for case 3. Adding the Na-rich fuel could also be problematic and more investigation has to be put into potential additives and fuels to compensate for the additional Na.When peat is fully phased out in case 1-3 the CO2 emission would decrease by 10 000 tonCO2/year. Due to the cost of CO2 emissions, this could result in considerable monetary savings. From the results it is estimated that case 1 could save 9.1 million SEK/year, case 2 10.3 million SEK/year, and case 3 6.5 million SEK/year when the peat is fully removed. This does not include changes in availability and maintenance costs. / Kemiindustriföretaget Perstorp AB har en 50 MWth cirkulerande fluidiserad bädd panna för att förse produktionen med processånga. Bränsleblandningen som används visar en stor variation med ett 20-tal olika bränslefraktioner som kan delas in i kategorierna returflis (RT-flis), slam, skogsbränsle, slaktrester, industrirester och torv. Från ett ekonomiskt- och miljöperspektiv bör användningen av torv minimeras eftersom den är klassad som ett fossilt bränsle. Dock har torv positiva förbränningsegenskaper vilket beror på dess innehåll av såväl svavel som kiselbaserade mineraler vilka minskar korrosions förmågan för alkali-klorider. Därför är det inte alltid möjligt att fasa ut torven utan att riskera att försämra pannans tillgänglighet. Andra aspekter förutom minskade CO2 utsläpp som är fördelaktiga vid drift av en panna, är att minimera användningen av tillsatser som kalksten samt använda restprodukter som bränsle i största möjliga mån. Dock kan, som i fallet med torv, en minskad användning av kalksten och ett nytt restproduktbränsle ha potentiella negativa konsekvenser för pannans tillgänglighet. Om kalksten används i mindre utsträckning kan risken för klumpbildning i pannan, agglomerering, öka och ofta kan restprodukter från produktionen innehålla höga halter av problematiska grundämnen både i ett korrosions och agglomererings perspektiv.Syftet med detta examensarbete har varit att undersöka möjligheterna att minska användningen av torv och kalksten samt möjligheten att tillföra ett nytt Na-rikt bränsle till bränsleblandningen. Detta undersöktes genom att först bestämma vad som eldades och i vilka mängder. Genom att använda data från leveransrapporter (för bränslen och additiv) och bränsleanalyser. I de fall det fanns representativ bränsleanalys användes dessa, i övrigt provtogs och beställdes nya bränsleanalyser. Med hjälp av erfaren personal som jobbar med pannan kunde olika möjliga framtida bränsleblandningar bestämmas. Dessa bränsleblandningar delades in i olika scenarion eller case som det kallas här: Case 1. Ersätta torv med skogsbränsle. Case 2. Ersätta torv med RT-flis. Case 3. Ersätta både torv och biomal (slaktrester) med RT-flis. Case 4. Introduktion av Na-rikt restbränsle. Baserat på en tidigare kartläggning av askomvandlingen i pannan kunde det teoretiska tillgängliga SO2 halten i rökgaserna bestämmas för varje case för tre olika kalkstenshalter. För varje case kunde sedan CO2 utsläppen samt de ekonomiska besparingarna estimeras då torv var helt urfasad och kalkstensinnehållet halverat. Från ett SO2 perspektiv pekar resultaten på att det skulle vara möjligt att fasa ut torven helt genom att minska kalkstenen mellan 0-50 vikt% för case 1 och 2 men inte för case 3. Att tillsätta det Na-rika bränslet kan potentiellt vara problematiskt. För att elda detta Na-rika bränslet kan det krävas en ny additiv eller ett S-rikt bränsle för att balansera tillskottet av Na och därmed minska korrosionsrisken.Vid utfasning av samtlig torv minskar CO2 utsläppen i case 1-3 med runt 10 000 tonCO2/år. Eftersom utsläpp av fossil CO2 är beskattat, uppskattas de möjliga besparingarna som betydande, 9.1 miljoner SEK/år i case 1, 10.3 miljoner SEK/år case 2 och 6.5 miljoner SEK/år i case 3 inklusive inköps- och askhanteringskostnader.

Pine tree substrate (PTS) produced from freshly harvested loblolly pine (Pinus taeda L.) trees has potential for replacing or reducing the use of aged pine bark (PB) and peat moss as container substrates for horticulture crop production. The objective of this work was to determine the factors influencing nutrient availability in PTS compared to PB or peat substrates. Chapter two reports data on the response of japanese holly and azalea to fertilizer rate when grown in PTS and PB. This study demonstrated that an additional 2.4 kg·m-3 of Osmocote Plus (15N-3.9P-10K) controlled release fertilizer is required for both species when grown in PTS compared to PB. Data are reported in chapter three on the effects of fertilizer rate, substrate particle size, and peat amendment on growth and floral quality, and on post-production time-to-wilting of poinsettias. Data from this work show that PTS requires an additional 100 mg·L-1 N to grow poinsettias comparable to plants grown in peat unless the particle size of PTS was decreased or 25% peat was added, in which case no additional fertilizer was needed. Results also indicated that PTS shrinkage was similar to that of peat, and that post-production time-to-wilting in PTS plants was similar as plants grown in peat. Data in chapter four compares nitrogen (N) immobilization rates, substrate carbon dioxide (CO₂) efflux levels, and nutrient leaching in peat, PB, and PTS over time. Data from these studies indicated that more N immobilization occurs in PTS than in PB or peat and that the substrate CO₂ efflux levels (estimate of microbial activity) corresponds to N immobilization in all substrates. Nutrient availability, changes in physical and chemical properties, substrate shrinkage, and microbial activity in PTS compared to PB during long-term nursery production are reported in chapter five. Results showed that substrate nutrient levels remain lower in PTS and that pH levels of PTS decrease considerably over two growing seasons compared to PB. Results also indicate that PTS does decompose over time in containers, but substrate shrinkage of PTS is similar to that of PL and PB during crop production. / Ph. D.

Freshwater is a finite resource that is rapidly becoming more scrutinized in agricultural consumption. Specialty crop producers, especially ornamental crop producers, must continually improve production sustainability, with regards to water resource management, in order to continue to stay economically viable. Soilless substrates were initially developed to have increased porosity and relatively low water holding capacity to ensure container crops would not remain overhydrated after irrigations or rain events. As a result, substrates were selected that are now considered to be in efficient in regards to water resource management. Therefore, to provide growers with additional means to improve production sustainability, soilless substrate hydrology needs be innovated to provide increased water availability while continuing to provide ample air filled porosity to ensure productive and efficient water interactions. Historically, soilless substrates have been characterized using "static" physical properties (i.e. maximum water holding capacity and minimum air-filled porosity). The research herein involves integrating dynamic soilless substrate hydraulic properties to understand how substrate hydrology can be manipulated to design sustainable substrates. This task involved adapting new technologies to analyze hydrological properties of peat and pine bark substrates by employing evaporative moisture characteristic measurements, which were originally designed for mineral soils, for soilless substrate analyses. Utilizing these evaporative measurements provide more accurate measures of substrate water potentials between -10 and -800 hPa than traditional pressure plate measurements. Soilless substrates were engineered, utilizing only three common substrate components [stabilized pine bark (Pinus taedea L.), Sphagnum peatmoss, and coconut coir fiber], via particle fractionation and fibrous additions. The engineering process yielded substrates with increased unsaturated hydraulic conductivity, pore connectivity, and more uniform pore size distributions. These substrates were tested in a greenhouse with irrigation systems designed to hold substrates at (-100 to -300 hPa) or approaching (-50 to -100 hPa) water potentials associated with drought stress. Substrate-water dynamics were monitored, as were plant morphology and drought stress indicators. It was determined that increased substrate unsaturated hydraulic conductivity within the production water potentials, allowed for increased crop growth, reduction in drought stress indicators, while producing marketable plants. Furthermore, individual plants were produced using as low as 5.3 L per plant. Increased production range substrate hydraulic conductivity was able to maintain necessary levels of air-filled porosity due to reduced irrigation volumes, while providing water for plants when needed. The substrates were able to conduct water from throughout the container volume to the plant roots for uptake when roots reduced substrate water potential. Furthermore, increased substrate hydraulic conductivity allowed plants within the substrate to continue absorbing water at much lower water potentials than those in unaltered (control) pine bark. Finally, HYDRUS models were utilized to simulate water flux through containerized substrates. These models allowed for better understanding of how individual hydraulic properties influence substrate water flux, and provided insight towards proportions of inaccessible pores, which do not maintain sufficient levels of available water. With the models, researchers will be able to simulate new substrates, and utilize model predictions to provide insight toward new substrates prior to implementing production tests. It has been determined, that increasing substrate hydraulic conductivity, which can be done with just commonly used components, water requirements for production can be reduced, to produce crops with minimal wasted water resources. Concluding, that re-engineering substrate hydrology can ameliorate production sustainability and decrease environmental impact. / Ph. D. / The world is rapidly approaching a time when water will become a limited resource, not only for agriculture, but all daily uses. As a result specialty crop production must continue to increase sustainability in order to continue to thrive. One area where growers and researchers believe environmental stewardship can be increased is through designing more resource efficient soilless substrates. Soilless substrates (potting media) are utilized world-wide by container crop producers as a rooting medium for specialty crops. These substrates were developed to be very forgiving for growers. By that, growers could apply excess water through irrigation or precipitations and these substrates were designed to readily drain excess water. This provides an opportunity to create more water efficient substrates to help reduce water consumption by container nurseries. The processes involving water-air-substrate interactions within the container are not well understood. As a result, my research involves measuring, manipulating, maintaining, and modeling substrate hydrology in an effort to design substrates that will conserve water in container production. I incorporated new technology used in Soil Science to measure hydraulic properties of soilless substrates through the evaporative method. I then understood how growers and allied suppliers can easily modify these substrate hydraulic properties. Next, I researched how these manipulated hydraulic properties would influence plant growth and vitality, by maintaining drought level irrigation levels over multiple crops. Finally, I modeled substrate hydraulic properties to better understand water movement through a container. Through the research herein, I was able to determine that substrate hydrology can be easily modified to provide container crops with more easily accessed water, while still keeping sufficient air-space for plant growth. Increasing unsaturated hydraulic conductivity in soilless substrates, allows ornamental crops to be held at lower water regimes moisture levels traditionally considered to be drought levels. Utilizing the HYDRUS model, I was able to determine how to develop future substrate models that will accurately simulate real-world outcomes, providing researchers with another tool to quickly predict impacts of newly developed (or still in development) soilless substrates on water status in container production.

The intermontane Ipswich Basin, which is situated 30km south-west of Brisbane, contains coal measures formed in the Late Triassic Epoch following a barren non-depositional period. Coal, tuff, and basalt were deposited along with fluvial dominated sediments. The Ipswich Coal Measures mark the resumption of deposition in eastern Australia after the coal hiatus associated with a series of intense tectonic activity in Gondwanaland during the Permo-Triassic interval. A transtensional tectonic movement at the end of the Middle Triassic deformed the Toogalawah Group before extension led to the formation of the Carnian Ipswich Coal Measures in the east. The Ipswich Coal Measures comprise the Brassall and Kholo Subgroups. The Blackstone Formation, which forms the upper unit of the Brassall Subgroup, contains seven major coal seams. The lower unit of the Brassall Subgroup, the Tivoli Formation, consists of sixteen stratigraphically significant coal seams. The typical thickness of the Blackstone Formation is 240m and the Tivoli Formation is about 500m. The coal seams of the Ipswich Basin differ considerably from those of other continental Triassic basins. However, the coal geology has previously attracted little academic attention and the remaining exposures of the Ipswich coalfield are rapidly disappearing now that mining has ceased. The primary aim of this project was to study the patterns of coal sedimentation and the response of coal seam characteristics to changing depositional environments. The coal accumulated as a peat-mire in an alluvial plain with meandering channel systems. Two types of peat-mire expansion occurred in the basin. Peat-mire aggradation, which is a replacement of water body by the peatmire, was initiated by tectonic subsidence. This type of peat-mire expansion is known as terrestrialisation. It formed thick but laterally limited coal seams in the basin. Whereas, peat-mire progradation was related to paludification and produced widespread coal accumulation in the basin. The coal seams were separated into three main groups based on the mean seam thickness and aerial distribution of one-meter and four-meter thickness contour intervals. Group 1 seams within the one-meter thickness interval are up to 15,000m2 in area, and seams within the four-meter interval have an aerial extent of up to 10,000m2. Group 1A contains the oldest seam with numerous intraseam clastic bands and shows a very high thickness to area ratio, which indicates high subsidence rates. Group 1B seams have moderately high thickness to area ratios. The lower clastic influx and slower subsidence rates favoured peat-mire aggradation. The Group 1A seam is relatively more widespread in aerial extent than seams from Group 1B. Group 1C seams have low mean thicknesses and small areas, suggesting short-lived peat-mires as a result of high clastic influx. Group 2 seams arebetween 15,000 and 35,000m2 in area within the one-meter interval, and between 5,000 and 10,000m2 within the four-meter interval. They have moderately high area to thickness ratios, indicating that peat-mire expansion occurred due to progressively shallower accommodation and a rising groundwater table. Group 3 seams, which have aerial extents from 35,000 to 45,000m2 within the one-meter thickness contour interval and from 10,000 to 25,000m2 within the four-meter interval, show high aerial extent to thickness ratios. They were deposited in quiet depositional environments that favoured prolonged existence of peat-mires. Group 3 seams are all relatively young whereas most Group 1 seams are relatively old seams. All the major fault systems, F1, F2 and F3, trend northwest-southeast. Apart from the West Ipswich Fault (F3), the F1 and F2 systems are broad Palaeozoic basement structures and thus they may not have had a direct influence on the formation of the much younger coal measures. However, the sedimentation patterns appear to relate to these major fault systems. Depocentres of earlier seams in the Tivoli Formation were restricted to the northern part of the basin, marked by the F1 system. A major depocentre shift occurred before the end of the deposition of the Tivoli Formation as a result of subsidence in the south that conformed to the F2 system configuration. The Blackstone Formation depocentres shifted to the east (Depocentre 1) and west (Depocentre 2) simultaneously. This depocentre shift was associated with the flexural subsidence produced by the rejuvenation of the West Ipswich Fault. Coal accumulation mainly occurred in Depocentre 1. Two types of seam splitting occurred in the Ipswich Basin. Sedimentary splitting or autosedimentation was produced by frequent influx of clastic sediments. The fluvial dominant depositional environments created the random distribution of small seam splits. However, the coincidence of seam splits and depocentres found in some of the seams suggests tectonic splitting. Furthermore, the progressive splitting pattern, which displays seam splits overlapping, was associated with continued basin subsidence. The tectonic splitting pattern is more dominant in the Ipswich Basin. Alternating bright bands shown in the brightness profiles are a result of oscillating water cover in the peat-mire. Moderate groundwater level, which was maintained during the development of the peat, reduced the possibility of salinisation and drowning of the peat swamp. On the other hand, a slow continuous rise of the groundwater table, that kept pace with the vertical growth of peat, prevented excessive oxidation of peat. Ipswich coal is bright due to its high vitrinite content. The cutinite content is also high because the dominant flora was pteridosperms of Dicroidium assemblage containing waxy and thick cuticles. Petrographic study revealed that the depositional environment was telmatic with bog forest formed under ombrotrophic to mesotrophic hydrological conditions. The high preservation of woody or structured macerals such as telovitrinite and semifusinite indicates that coal is autochthonous. The high mineral matter content in coal is possibly due to the frequent influx of clastic and volcanic sediments. The Ipswich Basin is part of a much larger Triassic basin extending to Nymboida in New South Wales. Little is known of the coal as it lacks exposures. It is apparently thin to absent except in places like Ipswich and Nymboida. This study suggests that the dominant control on depocentres of thick coal at Ipswich has been the tectonism. Fluvial incursions and volcanism were superimposed on this.

Present organic carbon fluxes from an upland peat catchment were quantified through measurement of in-situ direct and indirect greenhouse gas fluxes. To predict future greenhouse gas (GHG) fluxes, peat from eroded (E) and uneroded (U) site of an upland peat catchment was characterized.Composition of peat from E and U sites at the Crowden Great Brook catchment, Peak District Nation Park, UK that was characterized by Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS) at 700 oC. Pyrolysis products of the peat were then classified using the Vancampenhout classification into 6 compound classes - viz. aromatic and polyaromatic (Ar), phenols (Ph), lignin compounds (Lg), soil lipids (Lp), polysaccharide compounds (Ps) and N-compounds (N). There was no significant difference in the composition between the eroded and uneroded sites within the study area or between peats from different depths within each site. Nevertheless, there was a significant difference between sites in the proportions of Sphagnum that had contributed to the peat. Pyrolysis products of the peat were also classified into pedogenic (Pd) and aquagenic (Aq) OC – the mean percentage of Pd in both eroded and uneroded peats was 43.93 ± 4.30 % with the balance of the OC classified as Aq.Greenhouse gas (GHG) fluxes were quantified directly by in-situ continuous measurement of GHG was carried out at the E and U sites of the catchment using a GasClam: mean in-situ gas concentrations of CH4 (1.30 ± 0.04 % v/v (E), 0.59 ± 0.05 % v/v (U) and CO2 (8.83 ± 0.22 % v/v (E), 1.77 ± 0.03 % v/v (U)) were observed, with both the CH4 and CO2 concentrations apparently unrelated to atmospheric pressure and temperature changes. Laboratory measurements of ex-situ gas production - for both CH4 and CO2 this was higher for U site soils than for E site soils. At the U site, maximum production rates of both CH4 (46.11±1.47 mMol t-1 day-1) and CO2 (45.56 ± 10.19 mMol t-1 day-1) were observed for 0-50 cm depth in soils. Increased temperature did not affect gas production, whilst increased oxygen increased gas production. The CH4/CO2 ratios observed in-situ are not similar to those observed in the ex-situ laboratory experiments; suggest that some caution is advised in interpreting the latter. However, the maximum OC loss of 2.3 wt. % observed after 20 weeks of ex-situ incubation is nevertheless consistent with the long-term degradation noted by Bellamy et al (1985) from organic-rich UK soils. Indirect greenhouse gas (GHG) fluxes were quantified through the mass flux of suspended organic carbon (SsOC) drained from studied catchments. The SsOC was quantified by interpolating and rating methods. Unfiltered (UF) organic carbon (OC) fluxes in 2010 were calculated to be 8.86 t/km2/yr for the eroded sub-catchment and 6.74 t/km2/yr for the uneroded sub-catchment. All the rating relationships have a large amount of scatter. Both UF OC and <0.2 µm fraction OC are positively correlated with discharge at the eroded site, whilst there is no discernable relationship with discharge at the uneroded site. SsOC is dominated by Pd type OC (95.23 ± 10.20 % from E; 92.84 ± 5.38 % from U) far more so than in sources of the peats, suggesting slower oxidation of Pd (cf. Aq) OC.

Tropical forests have existed for up to one hundred million years, and today provide many ecosystem services vital for human well-being. They also harbour great biodiversity, which, in addition to its intrinsic value, plays a key role in the functioning of these ecosystems. Despite their local to global significance, there are still many knowledge gaps concerning the dynamic processes that govern the functioning of tropical forests. Rapid rates of deforestation and landscape conversion, predominantly for logging and industrial agriculture, are limiting the time and opportunity available to collect the information needed to fill these gaps. This research aims to shed light on the long-term ecological functioning of tropical forests, specifically investigating the history of disturbance in these ecosystems and the response of forest vegetation to past perturbations. The carbon-rich tropical peat swamp forests found along the coast of Sarawak, Malaysian Borneo, are a central focus of this study. For these forests in particular, a large deficit of knowledge surrounding their history and unique ecological functioning is coupled with some of the highest conversion rates of all tropical forest ecosystems across the world. In this thesis, palaeoecological data has been used to reconstruct temporal variability in forest vegetation coincident with external perturbations in order to identify changes in the resilience of these ecosystems through time, via indicators such as slowing rates of recovery and reduced regeneration of forest vegetation. Results suggest that tropical forest ecosystems have, for the most part, shown resilience to natural disturbances in the past, ranging from instantaneous localised tree-fall to longer-term regional climatic change; but that recent anthropogenic disturbances, of novel forms and greater intensities, are jeopardizing the potential for forest recovery and thus compromising ecosystem resilience. These findings enhance our understanding of the ecology of tropical peat swamp forests, and tropical forests more broadly. They also provide a context for contemporary tropical forest management, allowing for predictions on future responses to disturbance and enabling more ecologically sustainable landscape planning.