Mapping of Forest Alliances and Associations Using Fuzzy Systems and Nearest Neighbor Classifiers

The study and management of biological communities depends on systems of classification and mapping for the organization and communication of resource information. Recent advances in remote sensing technology may enable the mapping forest plant associations using image classification techniques. But few areas outside Europe have alliances and associations described in detail sufficient to support remote sensing-based modeling. Northwestern Montana has one of the few plant association treatments in the United States compliant with the recently established National Vegetation Classification system. This project examined the feasibility of mapping forest plant associations using Landsat Enhanced Thematic Mapper data and advanced remote sensing technology and image classification techniques. Suitable reference data were selected from an extensive regional database of plot records. Fifteen percent of the plot samples were reserved for validation of map products, the remainder of plots designated as training data for map modeling. Key differentia for image classification were identified from a suite of spectral and biophysical variables. Fuzzy rules were formulated for partitioning physiognomic classes in the upper levels of our image classification hierarchy. Nearest neighbor classifiers were developed for classification of lower levels, the alliances and associations, where spectral and biophysical contrasts are less distinct. Maps were produced to reflect nine forest alliances and 24 associations across the study area. Error matrices were constructed for each map based on stratified random selections of map validation samples. Accuracy for the alliance map was estimated at 60%. Association classifiers provide between 54 and 86% accuracy within their respective alliances. Alternative techniques are proposed for aggregating classes and enhancing decision tree classifiers to model alliances and associations for interior forest types

SOCIO-POLITICAL AND NATURAL-ECOLOGICAL FACTORS INFLUENCING URBAN FOREST MANAGEMENT IN MASSACHUSETTS

The management of urban forest systems is a complex interaction of social-ecological elements where biophysical factors interact with social aspects including policy decision-makers, managers, and municipal and private-sector employees. In the New England states, tree wardens are the local officials responsible for the preservation, maintenance, and stewardship of the public trees of a municipality. In-person qualitative research interviews were conducted with 50 tree wardens throughout Massachusetts to understand position duties, responsibilities, and professional challenges at the community-level. Qualitative research interviews were also conducted with chairs from 13 volunteer urban tree committees across Massachusetts. The value of employing qualitative methodologies in urban forestry, such as research interviews, as a mechanism to inform Extension professionals of stakeholder needs was also explored and further defined. Clearly emergent themes were identified from interview data and explored through analysis and comparison with existing literature. Tree wardens are typically housed in a municipal department, routinely interact with a number of local organizations, including urban tree committees, and are concerned about emergent plant health issues of importance including Asian longhorned beetle (Anaplophora glabripennis), emerald ash borer (Agrilus planipennis), and hemlock woolly adelgid (Adelges tsugae) (HWA). Since eastern hemlock (Tsuga canadensis) is one of only four native coniferous trees of ornamental importance in the Northeast U.S., and coniferous trees are notoriously underplanted in the urban environment, the ecology and natural history of its native and invasive insect and disease pests were reviewed in detail. These included HWA, elongate hemlock scale (Fiorinia externa), and shoestring root rot (Armillariaspp.). The use of pest resistant plant material – a strategy known to arborists and urban foresters as employing host plant resistance (HPR) – with applicability of HWA-resistant hemlock trees as potential substitutes for eastern hemlock plantings was explored. It was determined that HWA-resistant Chinese hemlock (Tsuga chinensis) would make a suitable surrogate ornamental planting for eastern hemlock in the urban environment

Development and Extrapolation of a General Light Use Efficiency Model for the Gross Primary Production

The global carbon cycle is one of the large biogeochemical cycles spanning all living and non-living compartments of the Earth system. Against the background of accelerating global change, the scientific community is highly interested in analyzing and understanding the dynamics of the global carbon cycle and its complex feedback mechanism with the terrestrial biosphere. The international network FLUXNET was established to serve this aim with measurement towers around the globe. The overarching objective of this thesis is to exploit the powerful combination of carbon flux measurements and satellite remote sensing in order to develop a simple but robust model for the gross primary production (GPP) of vegetation stands. Measurement data from FLUXNET sites as well as remote sensing data from the NASA sensor MODIS are exploited in a data-based model development approach. The well-established concept of light use efficiency is chosen as modeling framework. As a result, a novel gross primary production model is established to quantify the carbon uptake of forests and grasslands across a broad range of climate zones. Furthermore, an extrapolation scheme is derived, with which the model parameters calibrated at FLUXNET sites can be regionalized to pave the way for spatially continuous model applications

The utility of LiDAR for landscape biodiversity assessment

The potential of LiDAR to inform landscape biodiversity assessments is investigated. The objectives of this research are to examine how LiDAR discrete return and full waveform systems can be used to recover forest structure information, how LiDAR intensity can be used for biodiversity assessment and whether the utility of LiDAR can compliment traditional survey methods. Experiments using LiDAR discrete return and full waveform systems were conducted. An eight category forest characterisation scheme (FCS) derived from a LiDAR full waveform system was proposed and validated using field derived variables. Intensity variables derived from LiDAR full waveform were explored to determine its utility. The applicability of the proposed scheme was also examined by comparing two independent LiDAR full waveform datasets of the same area and by comparing to commonly used field-based biodiversity metrics. From these surveys, it was concluded that conventional discrete return systems can be used to recover forest structure information for forests with an ecologically simple structure. Vertically stratified LiDAR intensity, using range information, has potential to recover canopy cover, grass cover and the amount of fallen trees. The combination of LiDAR intensity mean and standard deviation can be used to differentiate forest types; sparse canopy with few fallen trees or dense canopy with many fallen trees. The LiDAR full waveform system experiment demonstrated that the FCS allows for quantification of gaps (above bare ground, low vegetation and medium vegetation), canopy cover and its vertical density as well as the presence of various canopy strata (low, medium and high). Regression analysis showed LiDAR derived variables were good predictors of field recorded variables. The FCS clearly showed the potential of full waveform LiDAR to provide information on the complexity of habitat structure. The exploratory analysis of intensity derived from LiDAR full waveform system displayed the potential of intensity variables to recover forest structure variables, however further study is required to account for the utility of intensity variables. In terms of the applicability of the FCS, a multiple dataset comparison showed that the FCS was resilient when recovering canopy cover, openings above the ground and medium vegetation, and presence of mid-storey vegetation and high trees, however it was less so when recovering openings above low vegetation, the presence of understorey vegetation and vertical canopy density of high trees. These last categories were considered to be affected by the difference in the pulse repetition frequency. Obtaining sufficient multiple returns by setting an appropriate pulse repetition frequency is the key to maintaining good performance of the scheme. The FCS was also found to be incompatible with commonly used field-based biodiversity metrics due to the qualitative and subjective measurements used in field-based metrics. Refinement in field methodology would be necessary for measuring structural variables to maximise the utility of FCS in their metrics. This study demonstrated how LiDAR technology can be used to derive forest structure information for landscape biodiversity assessment. The method proposed in this study is versatile, repeatable and quantitative, which can provide useful information to inform decisions and conservation strategies

Sistema Radical do sobreiro (Quercus suber L.): uma abordagem estrutural-funcional 3D

The last decades have witnessed the decline and sudden death of the cork oak (Quercus suber L.) in Montado. The complexity of this production system management has lead to a large set of solutions which have been absent by scientific based research findings (such as those related with the cork oak root system) deriving mainly from empirical knowledge application. The present integrated research approach permits a better understanding of the production system vulnerabilities that can result in management modification proposals which will be useful in a near future. To contribute to a more realistic and integrated forest management and planning, a study relying on a morphological evaluation of cork oak root system in a Cambissoil soil, using a 3D digitizing method was performed. Cork oak showed a dimorphic root system with a relative high quantity of sinkers distributed all over the soil profile, one root subsystem at a superficial level until 40 cm depth and another at a deeper level, around 1.20 m depth. Tree biomass allocation was similarly distributed between aerial and root systems. Previously, a study on methodologies for roots excavation - profile washing with water and excavation through high pressure air jet – was carried out. Results showed that for sandy soils the most suitable method is the excavation by high pressure air jet. Both methods showed to be inadequate for clayed soils. Following the evidence that soil compaction could be an important factor for root growth, a study was conducted, in a greenhouse, with cork oak seedlings. Results showed that tap root length and total root biomass (coarse and fine roots) are negatively affected by soil compaction in depth. In regard to the low survival rate of cork oaks regeneration that has been observed in Montado, another complementary study was conducted in a greenhouse where fertilisation, inoculation with mycorrhizal fungi and aminoacids supply were tested. It was concluded that seedlings subjected to fertilisation and inoculation had a more equilibrated growth between shoot and root components. It is expected that the research developed in the present thesis can provide an essential tool for future forest planning and management and for the natural and artificial regeneration processes in cork oak stands, ensuring the maintenance of the typical Montado landscape; Sistema Radical do Sobreiro (Quercus suber L.): Uma Abordagem Estrutural Funcional 3D Resumo: Desde as últimas décadas que se tem vindo a testemunhar o declínio e a morte súbita do sobreiro (Quercus suber L.) no Montado. A complexidade da gestão deste sistema de produção engloba um grande conjunto de soluções que, por terem sido ausentes de validação científica (tal como a relacionada com o sistema radical do sobreiro), tem vindo a ser suportado, principalmente, pela aplicação do conhecimento empírico. A presente abordagem integrada permite uma melhor compreensão das vulnerabilidades deste sistema que pode resultar em propostas de alteração de gestão que serão úteis num futuro próximo. De forma a contribuir para uma gestão e planeamento florestal mais realistas e integrados, foi realizado um estudo acerca da avaliação morfológica do sistema radical do sobreiro num cambissolo, usando o método de digitalização 3D. O sobreiro mostrou um sistema radicular dimórfico com uma elevada quantidade relativa de sinkers distribuídos por todo o perfil do solo. Foi observado um subsistema à superfície, até aos 40 cm de profundidade e outro mais profundo, a cerca de 1.20 m. Observou-se também que a biomassa da árvore foi distribuída de forma similar entre os sistemas aéreo e radical. Anteriormente foi conduzido um estudo sobre as metodologias de escavação de raízes - lavagem de perfil com água e escavação por meio de jato de ar de alta pressão. Os resultados mostraram que para solos arenosos, o método mais adequado é o método por meio de jato de ar de alta pressão e, que ambos os métodos mostraram ser inadequados para os solos argilosos. Após a observação de que a compactação do solo pode ser um fator importante para o crescimento das raízes, um estudo foi realizado em ambiente de estufa com plântulas de sobreiro. Os resultados mostraram que o comprimento da raiz principal e a biomassa total de raízes (raízes grossas e finas) foram negativamente afetados pela compactação do solo em profundidade. No que diz respeito à baixa taxa de sobrevivência da regeneração dos sobreiros, outro estudo complementar foi realizado em ambiente de estufa onde a fertilização, a inoculação com fungos micorrizos e o suplemento de aminoácidos foram testados. Concluiu-se que as plântulas submetidas à fertilização e inoculação tiveram um crescimento mais equilibrado entre as componentes aéreas e radicais. Espera-se que a investigação apresentada nesta tese possa proporcionar uma ferramenta essencial para o planeamento e gestão florestal futuros e, contribuir para o sucesso da regeneração natural e artificial dos povoamentos de sobreiro, garantindo a manutenção da paisagem típica do Montado

Academic Catalog: 2007-2008

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