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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Variabilidade espacial de atributos químicos do solo em variedades de Pinus / Spatial variability of soil chemical attributes on Pinus varieties

Ruiz, Juan Gabriel Cristhoffer Lopes [UNESP] 10 June 2016 (has links)
Submitted by JUAN GABRIEL CRISTHOFFER LOPES RUIZ null (juanboifran@hotmail.com) on 2016-08-16T18:47:46Z No. of bitstreams: 1 Tese_Juan Gabriel Cristhoffer Lopes Ruiz - versão final.pdf: 1062583 bytes, checksum: 48454ace721a06f1a1e4e08c0c10cb30 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-18T13:43:05Z (GMT) No. of bitstreams: 1 ruiz_jgcl_dr_jabo.pdf: 1062583 bytes, checksum: 48454ace721a06f1a1e4e08c0c10cb30 (MD5) / Made available in DSpace on 2016-08-18T13:43:05Z (GMT). No. of bitstreams: 1 ruiz_jgcl_dr_jabo.pdf: 1062583 bytes, checksum: 48454ace721a06f1a1e4e08c0c10cb30 (MD5) Previous issue date: 2016-06-10 / Estudos têm sido conduzidos para verificar as relações existentes entre o crescimento das florestas e os atributos químicos dos solos, responsáveis pelo potencial produtivo. O objetivo deste trabalho foi caracterizar e avaliar a variabilidade espacial de propriedades dendrométricas (altura e diâmetro a altura do peito) de povoamento de Pinus e a relação destes com os atributos químicos de um Latossolo Vermelho Amarelo do Instituto Florestal de Batatais –SP. Para o mapeamento dos teores de cálcio (Ca), magnésio (Mg), fósforo(P), potássio (K), matéria orgânica (MO), pH e acidez potencial (H+Al) as amostras de solos foram coletadas nos pontos de cruzamento de uma malha com intervalos regulares de 36 m, totalizando uma área de 16 hectares com espécies de Pinus, na profundidade de 0,0-0,20 m e 0,20-0,40 m, sendo coletadas 123 amostras em cada uma das duas profundidades, totalizando 246 amostras. Ao redor de cada ponto georreferenciado foram selecionadas nove árvores de Pinus, de maneira que cada ponto cadastrado fosse rodeado de forma uniforme, realizando-se as medidas de altura e diâmetro na altura do peito. Os dados foram submetidos à análise estatística descritiva, geoestatística e análises multivariadas. De acordo com os resultados obtidos, conclui-se que as árvores de Pinus apresentaram maior crescimento, com maiores valores de altura das árvores e do diâmetro na altura do peito, nas regiões em que os teores dos atributos químicos do solo foram maiores. O estudo mostrou que a análise multivariada foi eficiente para caracterizar os atributos químicos que foram mais sensíveis em discriminar as espécies de Pinus avaliadas sendo eles, o DAP, a altura da planta, Ca, Mg, K e pH com a Pinus caribaea var.bahamensis, e as variáveis H+Al, MO e P com a Pinus caribaea var.hondurensis. / Studies have been conducted to verify the relationship between the growth of forests and chemical properties of the soil that are responsible for the productive potential. The aim of this study was to characterize and evaluate the spatial variability of dendrometric properties (height and diameter at breast height) of pine stand , and Their relationship with the chemical attributes of an Oxisol of the Forest Institute of Batatais SP. For the mapping of the calcium (Ca), magnesium (Mg) , phosphorus (P) , potassium ( K ) , organic matter (OM), pH and potential acidity (H + Al) the soil samples were collected at the point of crossing a grid at intervals of 36 m, a total area of 16 hectares with pine species at a depth of 0,0 to 0,20 0,20-0,40 m, and collected 123 samples in each of the two depths, totaling 246 samples. Around each georeferenced point nine trees were selected Pinus, so that each spot was surrounded registered evenly. Then, there were the measures of height and diameter at breast height. The data were submitted to descriptive statistics, geostatistics and multivariate analysis. According to the results, it is concluded that the pine trees grew faster, with greater height values of trees and diameter at breast height, in areas where the levels of soil chemical properties were higher. The study revealed that the multivariate analysis was efficient to characterize the chemical attributes que Were most sensitive to discriminate Evaluated pine species . Being the diameter at breast height, plant height, Ca, Mg, K and pH Pinus caribaea var.bahamensis, and variable H + Al , OM an P with Pinus caribaea var.hondurensis.
2

Qualidade do plantio manual e mecanizado para eucalipto e pinus / Evaluation of planting quality of Eucalyptus spp. e Pinus spp. Using manual and mechanized method

Sereghetti, Guilherme Corrêa [UNESP] 28 November 2016 (has links)
Submitted by GUILHERME CORRÊA SEREGHETTI null (gcsereghetti@hotmail.com) on 2017-01-26T19:32:11Z No. of bitstreams: 1 Tese - Guilherme Corrêa Sereghetti com ficha.pdf: 1562635 bytes, checksum: 2225496033e17769d06fa8ed8f5d8a3b (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-01-30T15:43:18Z (GMT) No. of bitstreams: 1 sereghetti_gc_dr_bot.pdf: 1562635 bytes, checksum: 2225496033e17769d06fa8ed8f5d8a3b (MD5) / Made available in DSpace on 2017-01-30T15:43:18Z (GMT). No. of bitstreams: 1 sereghetti_gc_dr_bot.pdf: 1562635 bytes, checksum: 2225496033e17769d06fa8ed8f5d8a3b (MD5) Previous issue date: 2016-11-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O estudo avaliou a qualidade do plantio em dois sistemas diferentes, o mecanizado utilizando o equipamento Bracke Forest P11.a e o manual (convencional), além de apresentar uma visão econômica em relação à primeira experiência da utilização deste equipamento no Brasil. O experimento foi dividido em três etapas, sendo que em duas foram avaliadas a qualidade silvicultural e as variáveis dendrométricas (diâmetro do colo, diâmetro à altura do peito e altura da planta). Essas etapas ocorreram nas cidades de Bocaiúva, MG, onde se conduziu o experimento sob quatro tratamentos com cinco repetições, em que cada repetição era constituída por 60 mudas do híbrido Eucalyptus urophylla x Eucalypytus camaldulensis. A segunda etapa foi realizada em Telêmaco Borba, PR, onde se implantaram dois tratamentos com oito repetições, constituídos de 60 mudas de Pinus taeda e a última etapa, referente ao estudo econômico do plantio de Eucalyptus urophylla x Eucalyptus grandis em dois espaçamentos 3 × 1 m e 3 × 1,5 m utilizando o conjunto plantador, ocorreu em Lençóis Paulista, SP. Para as análises de comparações entre os tratamentos da qualidade silvicultural e as variáveis dendrométricas foi utilizado o teste LSMeans, do procedimento Genmod, por meio do software estatístico SAS – Statistical Analysis System. Os custos das máquinas foram calculados de acordo com a metodologia desenvolvida pela European COST Action, resultando em duas unidades: Euro por hora efetiva da máquina (€ h-1) e euro por muda (€ muda-1). As avaliações silviculturais da qualidade dos plantios evidenciaram que nas variáveis de substrato totalmente exposto e plantio inclinado não houve diferenças significativas nos sistemas de plantio mecanizado e manual de Eucalyptus urophylla x Eucalyptus camaldulensis e para Pinus taeda as análises não apresentaram diferença estatística para as variáveis de substrato parcialmente exposto, substrato totalmente exposto e plantio inclinado para os dois sistemas de plantio. As variáveis dendrométricas de diâmetro à altura do peito e altura de plantas obtiveram maior desenvolvimento aos doze meses após o plantio, no sistema de plantio mecanizado de Eucalyptus urophylla x Eucalyptus camaldulensi. Enquanto que para o plantio de Pinus taeda os maiores desenvolvimentos em diâmetro de colo das plantas foram observados no sistema manual aos doze meses após o plantio. A avaliação econômica teve como resultado que o maior espaçamento, 3 × 1,5 m, apresentou 11,9 % a mais no custo final em relação ao menor espaçamento de 3 × 1 m. / The study evaluated the quality of planting in two different systems, mechanized using the Bracke Forest P11.a device and manual (conventional), besides to present an economic vision for the first experience of using this device in Brazil. The experiment was divided into three stages, and two were evaluated silvicultural quality and dendrometric variables (stem diameter, diameter at breast height and plant height). These stages occurred in the cities of Bocaiúva, MG, where the experiment was conducted under four treatments with five repetitions, in each repetition consisted of 60 seedlings of the hybrid Eucalyptus urophylla x Eucalypytus camaldulensis. The second stage was executed in Telemaco Borba - PR where implanted two treatments with eight replications, made up of 60 seedlings of Pinus taeda and the last stage, referring to the economic study of the planting of Eucalyptus urophylla x Eucalypytus grandis in two spacings 3 × 1 m 3 × 1.5 m using the planter group, occurred in Lençóis Paulista - SP. For the analysis of comparisons between treatments silvicultural quality and dendrometric variables was used LSMeans test, the Genmod procedure, using the statistical software SAS - Statistical Analysis System. The operation costs were calculated according to the methodology developed by the European COST Action, resulting in two units: Euro per hour effective machine (€ h-1) and euro for seedlings (€ seedlings-1). The evaluations of the silvicultural quality of the plantings resulted that the variables fully exposed substrate and the inclined planting there were no significant differences in the mechanized and manual planting systems of the Eucalyptus urophylla x Eucalypytus camaldulensis and the Pinus taeda analyzes showed no statistical difference in the variables of partially exposed substrate, fully exposed substrate and planting inclined to the two planting systems. The dendrometric variables of the diameter at breast height and plant height had higher development at the twelve months after planting in the mechanized planting system of the Eucalyptus urophylla x Eucalypytus camaldulensi. While for the Pinus taeda planting the higher developments in the stems diameters of the plants were observed in the manual planting system at the twelve months after planting. The economic evaluation had as resulted that in the wider spacing, 3 × 1.5 m, showed 11.9% more in the final cost in relation to the narrower spacing of 3 × 1 m.
3

Croissance, fructification et régénération naturelle des peuplements artificiels de Pin pignon (Pinus pinea L.) au nord de la Tunisie / Croissance, fructification et régénération naturelle des peuplements artificiels de Pin pignon (Pinus pinea L.) au nord de la Tunisie

Adili, Boutheina 14 December 2012 (has links)
La régénération naturelle du Pin pignon (Pinus pinea L.) est difficile à atteindre. Ce processus est soumis à de multiples contraintes abiotiques et biotiques et leurs interactions qui demeurent partiellement connues. Une meilleure connaissance de ces facteurs est nécessaire pour la mise au point de recommandations sylvicoles en vue de favoriser la régénération. Compte tenu de la littérature disponible, nous avons supposé que l’établissement des semis de Pin pignon est contrôlé principalement, par ordre d’importance, par : (i) la disponibilité de la lumière, (ii) la biomasse des aiguilles de la litière et enfin (iii) la concurrence avec la végétation du sous-bois. En outre, l’étude a été complétée par une caractérisation de la structure du peuplement en termes de croissance et de fructification. L’établissement des semis de Pinus pinea a été étudié in situ et sous des conditions contrôlées pour trois forêts au nord de la Tunisie (Mekna III, Ouchtata II et Bechateur). Les semis vivants ont été comptés sur 90 placettes de 500m² chacune distribuées sur les trois forêts, et mis en relation avec la lumière disponible, la biomasse de la végétation du sous-bois et la biomasse des aiguilles de litière. Une expérience complémentaire a été menée dans des pots en conditions contrôlées sous serre avec des graines des trois forêts. Trois régimes de lumière incidente ont été appliqués (3%,16% et 58%) combinés avec trois modalités de lit de germination : sol nu, sol couvert d’aiguilles de litière et sol arrosé d’extrait d’aiguilles. L’étude a montré que la limitation de la germination n’était pas directement due à la lumière, mais plutôt à la température et à l’humidité liées à leur tour à la disponibilité de la lumière. L’émergence des semis a été significativement entravée par les couches de litière imposant une barrière mécanique, tandis qu’aucun effet chimiotoxique n'a été détecté. La végétation du sous-bois ne semble pas avoir joué un rôle important dans les premiers stades d’établissement des semis de Pinus pinea sous ces conditions climatiques méditerranéennes. Les besoins en lumière des jeunes plantules augmentent au fur et à mesure de leur développement et par conséquent le type d’interaction avec la végétation du sous-bois passe de la neutralité à la compétition. Nos résultats peuvent servir comme base initiale pour affiner la sylviculture afin d’améliorer l’établissement des pins. Le plan de gestion doit inclure une scarification afin de réduire l’épaisseur des couches de litière et des éclaircies intensives pour augmenter la disponibilité de la lumière. / Natural regeneration of Pinus pinea stands in Tunisia is difficult to achieve. This process is threatened by multiple abiotic and biotic stresses and their interactions which are still not well known, whereas, the knowledge of these factors is essential for sylvicultural recommendations. Given the available literature, we hypothesized that stone pine seedling establishment is mainly controlled in order of importance by (i) light availability, (ii) amount of needle litter, and (iii) competition with understory vegetation. Furthermore, the study was completed by a characterization of stand structure in terms of growth and fructification. The seedling establishment behaviour of Pinus pinea was studied under field and controlled conditions for three forests of north Tunisia (Mekna III, Ouchtata II and Bechateur). Live seedling were counted in 90 plots (500m² each) distributed in these forests, and related to light availability, biomass of understory vegetation, and biomass of needle litter collected in eight square subplots (0.5m × 0.5m). An additional experiment was conducted under controlled conditions in pots in greenhouse with seeds of the three forests. Three light regimes were applied (3%, 16%, and 58%) of incident light, combined with three seedbed modalities: bare soil, soil covered with needle litter and soil watered with needle extract. The study showed that germination limitation was not directly related to light, but rather to temperature and humidity linked to the light regime. Seedling emergence was significantly suppressed by litter layer which imposed a mechanical barrier, whereas no chemotoxic effect was detected. The understory vegetation did not appear to play a significant role in Pinus pinea early seedling establishment in these Mediterranean climate conditions. During the subsequent development of seedlings, their light requirement increased and their interactions with understory woody vegetation moved from neutral relationship towards a competitive relationship. We use our results to propose an initial silvicultural approach to favour pine establishment. A management plan should first include scarification to reduce litter thickness and then heavy thinning to significantly increase light availability.
4

Detecção e extração de vegetação utilizando dados lidar: determinação de indivíduos e aglomerados / Detection and extraction of vegetation using lidar data: determination of individuals trees and clumps

Barbosa, Lucas Jamiro 28 April 2017 (has links)
Submitted by Lucas Jamiro Barbosa (eng.lucasjb@gmail.com) on 2018-02-21T18:50:52Z No. of bitstreams: 1 barbosa_lj_me_prud.pdf: 5180173 bytes, checksum: 561a235397d5860ed83f8776cc40f6a4 (MD5) / Approved for entry into archive by ALESSANDRA KUBA OSHIRO ASSUNÇÃO (alessandra@fct.unesp.br) on 2018-02-21T19:37:41Z (GMT) No. of bitstreams: 1 barbosa_lj_me_prud.pdf: 5180173 bytes, checksum: 561a235397d5860ed83f8776cc40f6a4 (MD5) / Made available in DSpace on 2018-02-21T19:37:41Z (GMT). No. of bitstreams: 1 barbosa_lj_me_prud.pdf: 5180173 bytes, checksum: 561a235397d5860ed83f8776cc40f6a4 (MD5) Previous issue date: 2017-04-28 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O Sensoriamento Remoto tem-se mostrado, nos últimos anos, uma excelente ferramenta na aquisição de informações da cobertura da Terra. Dentre os diversos sensores remotos, o sistema de aquisição de dados por varredura LASER (Light Amplification by Stimulated Emission of Radiation) se apresenta como uma ferramenta poderosa na coleta de informações tridimensionais. A tecnologia lidar (Light Detection And Ranging), quando a bordo de aeronaves, pode ser denominada como Airborne Laser Scanning (ALS), diferente dos sistemas aerofotogramétricos de imageamento tradicionais, permite coletar, simultaneamente, pontos com coordenadas 3D sobre copas de árvores, bem como o terreno abaixo dela, em função da capacidade de registro de múltiplos retornos e da divergência do pulso. Por esta razão, esta tecnologia tem sido utilizada em diversas aplicações florestais, como manejo e recuperação florestal, silvicultura, exploração madeireira, dentre outras. Diversas pesquisas têm mostrado a possibilidade de utilização dos dados lidar na extração e delimitação de indivíduos arbóreos e, portanto, na estimativa de variáveis dendrométricas. Desta forma, o desenvolvimento de técnicas que proporcionem a automatização no delineamento das copas das árvores e na estimativa destas informações é de grande interesse. Contudo, grande parte das pesquisas relacionadas à detecção de árvores, delimitação de copa e estimativa de algumas variáveis são desenvolvidas considerando cenários homogêneos e específicos, onde a vegetação é caracterizada pela presença de árvores coníferas e/ou deciduais, ou florestas de exploração madeireira. Portanto, o objetivo desta pesquisa foi a implementação e avaliação de uma técnica que permita detectar indivíduos arbóreos e aglomerados, considerando um cenário urbano heterogêneo e complexo; e, destes indivíduos, estimar variáveis dendrométricas como área da copa; altura da árvore; e raio médio da copa. A metodologia proposta é realizada em três etapas e se baseia no uso do método de crescimento de regiões, aplicado à nuvem de pontos originais, ordenados quanto à altura. Além disso, são usados polígonos convexos visando a extração de indivíduos arbóreos e aglomerados. Para isso, são utilizados três parâmetros: distância mínima, buffer e perímetro comum. Foram realizados experimentos considerando dados reais e cenários diferentes em uma área urbana, para diferentes conjuntos de parâmetros utilizados no processo de delimitação das copas. Os mesmos foram avaliados quanto a acurácia temática, completeza e F-Score, calculados em função de referências obtidas de forma manual. Na delimitação de indivíduos arbóreos e aglomerados, simultaneamente, o maior valor de F-Score foi de 54% e na delimitação de indivíduos e aglomerados, em separado, o melhor resultado obtido foi 74% e 39%, respectivamente. Embora melhorias possam ser feitas visando aumentar estes indicadores, principalmente para aglomerados, pode-se considerar que o método proposto tem potencial de aplicação, sobretudo quando se tem por objetivo a extração de árvores individuais em ambiente urbano. / Remote Sensing has shown to be, in the last years, an excellent way of acquiring Earth’s surface data. Among all remote sensors, the system of data acquisition by LASER (Light Amplification by Stimulated Emission of Radiation) scanning has been presented as a powerful tool for three-dimensional information collection. lidar (Light Detection And Ranging) technology, when onboard of airplanes can be named Airborne Laser Scanning (ALS) and, differently from traditional photogrammetric techniques, allows the collection of simultaneously 3D points over tree crowns, as well as the ground underneath it, due to the recording capacity of multiple echoes arising from the divergence of the pulse. For this reason, this technology has been used in many different forest applications, as management and forest recovery, forestry, logging and others. Some researchers have shown the possibility of using lidar data on tree extraction and crown delineation and, therefore, on the estimation of their dendrometric variables. In this way, the development of techniques that can provide the automation of tree crowns delineation and estimation of this information has increased. However, most of the researches performed ever related to tree detection, canopy delineation and estimation of some dendrometric variables are developed considering homogeneous and specific scenarios where the vegetation is characterized by the presence of coniferous and/or deciduous trees. For this purpose, the objective of this research was the implementation and evaluation of a technique capable of detecting individual trees and clumps, considering a heterogeneous urban scenario. Additionally, from those individual trees some dendrometric variables such as crown area; tree height and average crown radius were estimated. Experiments were conducted considering different study areas in an urban environment varying the parameters used in the crown delineation process. Those experiments were evaluated in terms of thematic accuracy, completeness and F-Score, computed based on reference values obtained manually. When the simultaneous delimitation of arboreal individuals and agglomerates was performed the best F-Score was 54%. For independent processing, the best result was 74% and 39%, respectively, for individuals and agglomerates. Although improvements can be performed aiming to improve those indicators, mainly to clumps, it is possible to consider that the proposed method has potential, especially when the objective is the extraction of individual trees in an urban environment.
5

Mimosa scabrella Benth. (FABACEAE): Fundamentos para o manejo e conservação / Mimosa scabrellaBenth. (FABACEAE): Fundamentals for the management andconservation

Ferreira, Paula Iaschitzki 16 April 2015 (has links)
Made available in DSpace on 2016-12-06T17:42:07Z (GMT). No. of bitstreams: 1 PGPV15DA019.pdf: 1647519 bytes, checksum: 1d5c0783923ddc331d153e95b7e62281 (MD5) Previous issue date: 2015-04-16 / Mimosa scabrella Bentham, is a pioneer species, native and endemic to Brazil, occurring mainly in secondary training in Araucaria Forest. Known popularly as bracatinga, has potential for supply chain development in the Plateau of Santa Catarina, because wide range of timber and non-timber products. Due to the lack of ecological information and productive character of M. scabrella, this study aimed to characterize demographics (population structure and dynamics), spatial distribution, dendrometric growth, carbon content and the amount of CO2 equivalent, relate the potential increment of biomass under the action of abiotic factors and to verify the potential facilitator of this species in the successional advance in areas where restoration. Populations of M. scabrella studied are at different stages of development located in Bocaina do Sul, Lages, Ponte Alta and Urupema. Three sample units were allocated/population, measuring 40x40m, subdivided into sub-plots 10x10m, with a total sampling area 1.92 ha. All individuals of M. scabrella present within the limits of 12 demarcated sampling units were identified with aluminum plates and monitored for two evaluation periods (2012 and 2013). All individuals present in each sample unit were measured as the diameter at breast height (DBH) for adults (DBH ≥ 5 cm to 1.3 meters high); The diameter of soil height (DAC) for regenerating (DBH ˂ 5 cm at 1.3 meters height). Were evaluated following environmental variables: soil chemistry, relief (slope) and canopy cover. The survey of the diversity of the community regenerating in the understory of the population was evaluated in two sample/population units with dimensions of 40x20m, totaling 800 m²/population, was sampled all individuals with height ≥ 10 cm. The initial stages of development of populations of M. scabrella were marked by the occurrence of natural thinning, arising from pressures imposed by intraspecific competition. The diameter distribution in the populationat an early stage showed high concentration of individuals in the early grades and unimodal distribution in populations at a more advanced stage. The spatial distribution pattern of M. scabrella is compatible with those reported for other pioneer species. These populations demonstrate potential to provide environmental services regarding the carbon capture and storage. The dynamic rates were defined by the absence of recruitment in all populations and increased mortality in higher density (younger). Gains in basal area of each population had relationships with different environmental variables, which are: soil fertility, slope and canopy cover. The areas where natural regeneration in understory of M. scabrella of different ages, show different floristic-structural patterns, which are consistent with the trends succession dynamics characteristics of Araucaria Pine Forest, where most wealth and abundance of regenerating individuals was recorded in M. scabrella sub-woods with more advanced age / Mimosa scabrella Bentham é uma espécie pioneira, nativa e endêmica do Brasil, ocorrendo principalmente em formações secundárias de Floresta Ombrófila Mista. Conhecida popularmente como bracatinga, apresenta potencial para desenvolvimento da cadeia produtiva no Planalto Catarinense, devido ao amplo espectro de produtos madeiráveis e não madeiráveis que pode oferecer. Em decorrência da escassez de informações ecológicas e de caráter produtivo de M. scabrella, este estudo objetivou caracterizar aspectos demográficos (estrutura e dinâmica populacional), distribuição espacial, crescimento dendrométrico, teor de carbono e a quantidade de CO2 equivalente, relacionar o potencial de ganho de biomassa sob ação de diferentes variáveis ambientais, assim como verificar o potencial facilitador desta espécie quanto ao avanço sucessional em áreas em restauração. As populações de M. scabrella estudadas estão em diferentes estádios de desenvolvimento (idade) situadas nos municípios de Bocaina do Sul, Lages, Ponte Alta e Urupema. Foram alocadas três unidades amostrais por população, com dimensões de 40x40m, subdividas em sub-parcelas de 10x10m, totalizando uma área amostral 1,92 ha. Todos os indivíduos de M. scabrella presentes nos limites das 12 unidades amostrais demarcadas foram identificados com placas de alumínio e monitorados durante dois períodos de avaliação (2012 e 2013). Todos os indivíduos presentes em cada unidade amostral foram medidos quanto o diâmetro a altura do peito (DAP), para os indivíduos adultos (DAP ≥ 5 cm a 1,3 metros de altura); o diâmetro a altura do colo (DAC), para os indivíduos regenerantes (DAP ≤ 5 cm a 1,3 metros de altura). Em cada sub-parcela foram avaliadas as seguintes variáveis ambientais: química do solo, relevo (declividade) e cobertura do dossel. O padrão de distribuição espacial foi calculado pelo Índice de Morisita para as diferentes populações e a quantidade de CO2 equivalente pela estimativa do carbono total. O levantamento da diversidade da comunidade regenerante no sub-bosque das populações foi avaliada em duas unidades amostrais por população, com dimensões de 40x20m, totalizando 800 m²/população, onde foram amostrados todos os indivíduos com altura ≥ 10 cm. As fases iniciais de desenvolvimento das populações de M. scabrella foram marcadas pela ocorrência de desbastes naturais, oriundo das pressões impostas pela competição intraespecífica. A distribuição diamétrica na população em estádio inicial demonstrou alta concentração de indivíduos nas primeiras classes e distribuição unimodal nas populações em estádio mais avançado. O padrão de distribuição espacial de M. scabrella é compatível com aqueles registrados para outras espécies pioneiras (população em estádio inicial = agregado; estádio avançado = aleatório). Estas populações demonstram potencialidades de prestação de serviço ambiental no que tange o sequestro e estocagem de carbono. As taxas de dinâmica foram definidas pela ausência de recrutamento em todas as populações e maior mortalidade na população de maior densidade (mais jovem). Os ganhos em área basal de cada população apresentaram relações com distintas variáveis ambientais, sendo estas: fertilidade do solo, declividade e cobertura do dossel. As áreas em regeneração natural, em sub-bosques de M. scabrella com diferentes idades, apresentaram diferentes padrões florístico-estruturais, os quais são compatíveis com as tendências características da dinâmica sucessional de Floresta Ombrófila Mista, onde a maior riqueza de indivíduos regenerantes foi registrada nos sub-bosques de M. scabrella com idade mais avançadas
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Contribution à l'intégration des cycles biogéochimiques dans les modèles de croissance forestier à base phénoménologique. Dynamique saisonnière du couvert forestier et décomposition de la matière organique du sol / Contribution to the integration of biogeochemical cycles to phenomenological forest growth models. Seasonal dynamics of forest cover and decomposition of soil organic matter

Sainte-Marie, Julien 09 September 2014 (has links)
La communauté scientifique, en relation avec les gestionnaires forestiers, travaille depuis trente ans à l'élaboration d'outils d'aide à la décision. Cependant, aucune approche de modélisation ne permet une évaluation simultanée de l'impact sur la forêt des changements globaux et de la gestion des services écosystémiques. L'élaboration d'une nouvelle génération de modèles dédiés au couplage sol-plante est indispensable pour aider les gestionnaires forestiers à adapter leurs pratiques sylvicoles face aux changements globaux. Les modèles phénoménologiques issus de la dendrométrie proposent des estimations de croissance et de production tenant compte des pratiques sylvicoles. Leur utilisation est limitée par leur dépendance à un indice de fertilité combinant de manière indifférenciée l'influence du climat et des cycles biogéochimiques. La remise en jeu de la notion d'indice de fertilité nécessite de tirer avantage des concepts issus des modèles à base écophysiologiques et biogéochimiques. La modélisation de la dynamique mensuelle du renouvellement foliaire par le modèle Stand Leaf Canopy Dynamics a permis d'estimer: i) la dynamique de l'indice foliaire, ii) la production de litière foliaire. Ce modèle probabiliste tient compte de l'influence du climat, de la disponibilité en eau de l'écosystème et repose sur des hypothèses écologiques fortes sur les mécanismes impliqués dans la longévité des feuilles. Ce modèle pose les bases de l'intégration du cycle de l'eau aux modèles dendrométriques par couplage avec un modèle écophysiologique. Le modèle de décomposition de la matière organique le long d'un profil de sol vertical proposé par Bosatta et Ågren (1996) a été analysé mathématiquement afin d'étudier le devenir des chutes de litières dans le sol forestier. Nous avons proposé: i) une preuve d'existence et l'unicité de solutions à l'équation de transport intégro-différentielle du modèle, ii) des schémas de différences finies implicites-explicites convergents estimant les solutions du modèle et iii) une discussion autour des hypothèses sous-jacentes à une troncature du modèle proposée par Bosatta et Ågren. Ces deux étapes sont des leviers indispensables à l'étude des cycles biogéochimiques dans une approche à base dendrométrique. L'influence du climat et de la phénologie sur le cycle de l'eau, la décomposition des litières foliaires et la chimie du sol constituera une prochaine étape de modélisation. / The scientific community, in collaboration with forestry managers, developed decision support tools since thirty years. However, current modelling approaches do not allow simultaneous estimations of global changes impact management policies on forests. The design of a new generation of models dedicated to soil-plant coupling is necessary to help forest managers to adapt forestry practices to face global changes. Phenomenological models arising from dendrometry estimate forest growth \& yield and take into account of silvicultural practices. Their use is limited by their dependence to a fertility index, which combines implicitly the influence of climate and biogeochemical cycles. A re-examination of fertility index concept is necessary to take advantage of concepts developed in ecophysiological and biogeochemical models. Modelling the monthly dynamics of foliar renewal with the Stand Leaf Canopy Dynamics model permited: i) to estimate leaf area index dynamics, ii) to model foliar litter production. This probabilistic model takes into account climate influence, ecosystem water availability and lies on strong ecological hypothesis on mechanisms involved in leaf longevity. This model, associated with an ecophysiological model, permits to integrate water cycle to dendrometric models. The soil organic matter decomposition along a vertical soil profile model introduced by Bosatta et Ågren (1996) was analyzed to study the future of litterfall in forest soil. We proposed: i) a proof of existence and uniqueness of solutions to the integro-differential transport equation of the model, ii) convergent implicit-explicit finite differences schemes estimating model solutions and iii) a discussion on hypothesis underlying a model truncation introduced by Bosatta et Ågren. These two modelling steps are essential to consider biogeochemical cycle with a dendrometric approach. Climate and phenology influence on water cycle, litterfall decomposition and soil chemistry are the elements of a future modelling phase.

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