This thesis examines principles surrounding the use of multi-angle remote sensing to exploit effects of canopy shadowing on tropical forest bi-directional reflectance and thus provide improved tropical forest structural variable estimates. Remote sensing provides an invaluable source of information on inaccessible tropical forests. To date, the extraction of reliable and replicable forest canopy information from remotely sensed data has proved difficult. Recently, sensors have been developed which are able to view the Earth's surface from multiple angles. This extra dimension in reflectance data is expected to improve the estimation of canopy variables by exploiting the functional relationships between forest structure and anisotropic reflectance. Shadow is an important scene component known to influence reflectance in the optical spectrum.

Forest ecosystems contribute substantially to biogeochemical processes on the earth. Understanding their responses to climate change is essential to the prediction of future climate as they could accelerate or decelerate the rates at which atmospheric CO2 concentrations and associated global temperatures are rising, depending on their carbon (C) storage capacity. However, very little is known about how mature forests respond to climate change, particularly those growing under P limitation, or NP co-limitation. This thesis aimed to investigate the effects of elevated (e)CO2 (ambient +150 ppm) on soil nutrient dynamics and understorey plant community composition in a novel field CO2 exposure experiment in a mature, P-limited, native Eucalyptus woodland (EucFACE). It also investigated the effects of elevated temperature (eTemp; ambient +3 °C) on soil nutrient dynamics using whole-tree chambers (WTCs) in which Eucalyptus tereticornis trees were grown. I found seasonally-dependent positive effects of eCO2 on the availability and turnover of soil N and P over an 18-month period, with concurrent higher concentrations of dissolved organic carbon (DOC) in soil solution and lower soil pH. P availability was enhanced to a greater extent than N, resulting in decreased N:P ratios. The WTC experiment showed that, whilst eTemp enhanced P turnover and availability, and increased DOC in soil solution, effects on N availability and turnover were not statistically significant. In the case of both eCO2 and eTemp, increased DOC alongside increased soil P availability and decreased soil N:P ratios, suggests that plants adjusted their C investment strategies as their demand for nutrients, particularly P, increased. The EucFACE experiment also showed that eCO2 increased C3 plant species abundance compared to C4, and decreased species diversity in the understorey community. This thesis provides novel insights into and empirical evidence of soil nutrient, particularly P, dynamics under P-limited ecosystems in a higher CO2 and warmer world.

Vegetation structure provides a direct link between forest ecosystem productivity and earth-atmosphere fluxes, and is both a result and driver of these interactions. Therefore, the ability to collect objective, quantitative and three-dimensional measurements of vegetation structure is essential, particularly in light of climate change. However, a significant challenge still remains as to how to best measure changes in forests and prepare for future climatic scenarios. Terrestrial Laser Scanning (TLS) has shown its potential to provide such measurements, offering a new approach to monitoring how forest systems change through time and space. The overall aim of this thesis was to improve the characterisation of the seasonal dynamics of UK woodland vegetation structure using the Salford Advanced Laser Canopy Analyser (SALCA), a research TLS with dual-wavelength full-waveform capabilities. There were three key objectives to this research: (1) the development of a radiometric calibration for the SALCA instrument to produce an apparent reflectance product, (2) the separation of SALCA point clouds into leaf and wood on a tree and plot scale using dual-wavelength lidar, and (3) the examination of the seasonal dynamics of vegetation structure in a range of UK forest types. To address these objectives, two field campaigns were conducted. SALCA measurements of artificial reflectance targets were acquired from both field campaigns to generate a calibration dataset to address Objective 1. The two field campaigns comprised a tree-scale validation experiment at Alice Holt Forest (to address Objective 2), and a multi-temporal monitoring experiment using SALCA and hemispherical photography at Delamere Forest in five different plots (to address Objective 3). Key findings relating to Objective 1 have highlighted the complexities of SALCA intensity response, such as the effect of internal temperature. As a result, a novel approach to radiometric calibration was developed using artificial neural networks which produced an apparent reflectance product with measured accuracy comparable with other approaches. A key conclusion of this research relating to Objective 2, is that dual-wavelength TLS has the potential to aid separation of leaf and wood material. However, there still remain significant ecological, instrumental, and processing challenges to be overcome. Temporally and vertically resolved plot measurements have provided a quantitative analysis of foliage dynamics to address Objective 3 and results have shown how this differences between species. The research presented in this thesis has explored the use of dual-wavelength full-waveform TLS for improved characterisation of forest vegetation. Future research priorities should focus on the radiometric calibration and investigation of other methods for leaf-wood separation to extend and complement this research.

No description available.

This study set out to explore the hypothesis that previously undisturbed Amazonian terra firme (non-flooded) tropical forests show a gradient in resilience to selective logging as a function of tree species functional composition and in particular a positive relation with the presence of a specific ecological guild regarded as intermediate in the process of ecological succession known as the light hardwoods (LHW's). Field data came from the Manaus and Tapajos regions in Brazil and the Puerto Maldonado region in Peru. In response to drought stress induced canopy opening which is the natural disturbance analogue to selective logging, there was a significantly better performance in terms of turnover (diameter growth, mortality and recruitment) of the LHW's relative to climax species. Inresponse to selective logging trees growing within logging gaps showed a similar growth performance gradient 3 years after logging when species ecological guild was not taken under account. In series simulation experiments where conducted to determine actual stand levelcompositional and biomass responses to logging. Forest dynamics models in the SYMFORframework were used to conduct simulations of the most common logging practices. Results indicated that functional composition deviation from undisturbed forest showed a positive relation with resilience with LHW's proportions but only up to a certain threshold. Above this their proportion was positively related with deviation from primary forest conditions and therefore negatively related to resilience. A similar pattern was observed for stand basal area with intermediate sites showing the greatest resilience. For sites with low and medium proportions the opposite pattern was observed with sites of highest proportions showing the second greatest resilience followed by sites with lowest. This study indicates that there is a positive correlation between proportions of LHW trees in a forest stand and resilience to selective logging as currently practiced in the Brazilian Amazon but only up to a certain compositional threshold in functional composition.

Sustainable harvesting of non-timber forest products (NTFPs) and associated livelihood security can be compromised by changes in the broader ecosystem. This study investigates mistletoe infection of Amla, Phyllanthus emblica and Phyllanthus indofische7i, an NTFP of significant livelihood importance, in the Biligiri Rangaswarny Temple (BRT) Wildlife Sanctuary in southern India. Infection patterns of the Loranthaceae mistletoe, Taxillus tomentosus, were characterised across the Amla population and their underlying mechanisms explored. Two alternative management approaches were investigated, and traditional ecological knowledge documented and assessedfo r its concordance and additionality to scientific data. A high prevalence of infection, and the apparent greater susceptibility of the more significant resource species, suggests that mistletoe infection has serious implications for Amla sustainability. Traditional knowledge provided novel information on infection spread, and highlighted failings in current population assessments, emphasising the importance of a multidisciplinary approach to assessing sustainability. Traditional approaches to management conflict with current institutional perspectives, but may be somewhat more effective and require further investigation. However, existing data, both from scientific studies and traditional knowledge, are insufficient to prescribe with certainty the best approach to mistletoe control. The participatory implementation of an active adaptive management programme may offer benefits over alternative management options for securing Amla as a viable NTFP harvesting system.

No description available.

No description available.

Halting biodiversity loss and the associated decline of ecosystem functioning is one of the greatest challenges faced by mankind. The globally adopted Aichi Biodiversity Targets for 2011-2020, issuing from the 10th Conference of the Parties of the Convention on Biological Diversity, represent the strongest global commitment to this challenge. For forest ecosystems, biodiversity decline can be halted only with i) sustainable management of multifunctional production forests (Target 7), ii) formation of well-connected systems of protected areas (Target 11), and iii) forest restoration (Target 15). Reaching these targets for the world’s forests requires a sound empirical understanding of the functioning and the relative importance of forests under different management regimes. Indeed, environmental policy should be informed by robust scientific evidence. This thesis addresses knowledge gaps that exist in the evidence-base for sustainable forest management and conservation in temperate and boreal forests. Chapter 2 quantifies the recovery rates of different functional groups of beetles, lichens and fungi to forest restoration measures in temperate and boreal regions across the world. A systematic review and meta-analysis identifies functional-group-specific relationships in the response of species richness to stand age after forest disturbance, with some groups requiring around a century of stand continuity for recovery to old-growth levels. The slow recovery of these functional groups makes old-growth forest an effectively irreplaceable biodiversity resource that should be exempted from restoration offset initiatives. Chapter 3 compares the biodiversity value of overmature even-aged planted and old-growth forest stands for ectomycorrhizal fungi in the New Forest National Park, UK. Overmature plantations are those beyond economic maturity, acquiring some of the structural characteristics of old-growth forests and there is increasing interest in their setting aside as a means of preserving species associated with old-growth forests. Analysis of 3 years of field data shows that setting aside of overmature planted forest is an effective means of conserving ectomycorrhizal communities associated with old-growth forests, given temporal continuity in the order of a century. This holds out particular promise for historically deforested regions such as the UK, where little old-growth forest remains and much planted forest exceeds a century in age. Chapter 4 investigates the relative importance of abiotic and biotic drivers of carabid functional trait diversity and composition for coniferous production forests across the UK. Analysis of the dataset of the UK Forestry Commission’s Biodiversity Assessment Project (BAP 1995-1999) contradicts previous studies in showing that ground vegetation diversity is not an important determinant of carabid functional diversity. This result suggests that restoration of plant communities, a major goal of forest restoration efforts, will not necessarily enhance carabid diversity in coniferous plantations. Canopy cover was the most important variable, tending to drive down carabid diversity. Chapter 5 collates an evidence base that will inform forest biodiversity conservation and policy-making in Japan. Four management interventions, outlined in Japan’s National Biodiversity Strategy, are assessed by systematic review and meta-analysis for their impacts on species richness, abundance and composition. The work provides general guidance for forest biodiversity conservation in Japan, and it highlights a major knowledge gap in a widely used contemporary intervention known as ‘satoyama’.

The fungal floras of several Calluna-heathland soils distributed over England and Wales were investigated by the soil plate method. Many species of fungi (including Trichoderma viride. Mucor ramannianus, Beauveria bassiana, PeniciIlium adametzi, P. namyslowskii, P. nigricans, Trichobotrys sp., Absidia orchidis, Mortierella isabellina, Pullularia pullulans, and Zygorrhynchus vuilleminii) were found to be of more or less constant occurrence in these soils. Representatives of all major classes of fungi, excepting Oomycetes, were isolated. The numbers of species of fungi decreased with increasing depth, although certain species (Mucor ramannianus, Beauveria bassiana and Trichobotrys sp.) were most commonly isolated from the sub-surface, leached horizons. Evidence suggested that the illuviated horizons checked the downward distribution of spore-producing species. The fungus flora of one small area of heathland soil wasinvestigated in greater detail, on a seasonal basis, byseveral recently described methods of isolation including the immersion tube and a new slide-trap method. The latter two methods, designed to isolate only those fungi actively growing in the soil, yielded closely agreeing results; many of the species of fungi shown to be of constant occurrence by the plating method were isolated also as active mycelia. Many of the species isolated, however, varied according to the method employed. Microscopical examination by the Rossi-Cholodny slide technique revealed the growth habit of many of the species isolated and also the presence of many species which were not isolated - largely humus-inhabiting, dark-coloured hyphomycetes. Whilst no seasonal variation in the occurrence of fungi was demonstrated by the plating method, marked variation was demonstrated by the immersion tube method, In particular the isolation of Trichoderma viride was closely related to the prevailing temperature. The use of several methods of isolation, in conjunction with investigations of specific habitats and microscopical examination, provided a useful means of approach to the problems of soil fungal ecology.