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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

Assessment of a Seedling-Based Approach to Aspen Restoration in the Intermountain West

Howe, Alexander Addison 01 May 2018 (has links)
Quaking aspen (Populus tremuloides) is an important species ecologically and culturally in the western U.S., where it is one of the only broadleaf trees in the mostly conifer-dominated forests. Aspen management in the West has focused on regenerating existing stands vegetatively through root suckering, however this approach is restricted to locations where aspen currently exists and limits the genetic diversity of aspen populations. Planting nursery-grown aspen seedlings offers a potential method for overcoming these limitations, but it has received little attention in the U.S. Intermountain West (IW) to date. In order for this approach to be more broadly implemented, nursery protocols designed to grow high-quality aspen seedlings are needed, along with an understanding of what the major challenges to seedling establishment will be. With the assistance of my committee, my research tested a seedling-based approach to aspen restoration in an IW context in two phases. I first used nursery protocols developed for boreal aspen to grow seedlings collected from IW sources in order to assess whether modification of the protocols would be necessary. I then planted the seedlings I grew at three sites in southwestern Utah and monitored their growth and survival over two years. Results from the nursery phase suggest that protocols will need to be modified in order to produce a more consistent response from IW aspen seedlings. In the field, only 10% of the seedlings survived, though the majority of survival occurred in just two locations where soil moisture remained highest during the driest part of the early summer. These results provide useful information to direct future research and suggest that with a better understanding of appropriate site selection, seedling-based aspen restoration could still become a viable management tool in the IW.
2

Comparing Vegetation Cover in the Santee Experimental Forest, South Carolina (USA), Before and After Hurricane Hugo: 1989-2011

Cosentino, Giovanni R 03 May 2013 (has links)
Hurricane Hugo struck the coast of South Carolina on September 21, 1989 as a category 4 hurricane on the Saffir-Simpson Scale. Landsat Thematic mapper was utilized to determine the extent of damage experienced at the Santee Experimental Forest (SEF) (a part of Francis Marion National Forest) in South Carolina. Normalized Difference Vegetation Index (NDVI) and the change detection techniques were used to determine initial forest damage and to monitor the recovery over a 22-year period following Hurricane Hugo. According to the results from the NDVI analysis the SEF made a full recovery after a 10-year period. The remote sensing techniques used were effective in identifying the damage as well as the recovery.
3

Landscape Ecology of Large Fires in Southwestern Forests, USA

Haire, Sandra L. 01 February 2009 (has links)
The recent increase in large fires in southwestern forests has prompted concern regarding their ecological consequences. Recognizing the importance of spatial patterns in influencing successional processes, I asked: (1) How do large fires change plant communities?; (2) What are the implications of these changes for ponderosa pine forests?; and (3) What is the relationship of fire severity to gradients of climate, fuels, and topography? To address the first two questions, I studied succession in the woody plant community at two sites that burned in high-severity fire: La Mesa fire in northern New Mexico (1977) and Saddle Mountain in northern Arizona (1960). After large fires, abiotic conditions, associated prefire plant distributions, and spatial patterns of burning interacted to result in particular successional outcomes. Variation in abundance and diversity of species that spread from a refuge of seed sources remaining after the fire followed the model of wave-form succession. I investigated the implications of large fires for ponderosa pine by examining the influence of spatial patterns of burning on regeneration. Tree density corresponded most closely with particular scales of seed dispersal kernel and neighborhood severity metrics. Spatial patterns of burning remained influential even after consideration of variables describing subsequent burning and the physical and biotic environment. Age structure of young forests indicated that populations spread in a moving front and by long-distance dispersal. To explore the relationship between fire severity and climate, I investigated how the spatial heterogeneity of high-severity patches varied among 20 fires across gradients in fire size and climate. The largest fires generally occurred during cool dry La Niña climates, however, several fires deviated from this trend. Some spatial properties of severity did not correspond to fire size or to changes in climate. Characteristics of fuels and topography altered spatial patterns of severity, but interactions with extreme burning conditions may have disrupted these local influences in both La Niña and El Niño fires. Spatial patterns of fire severity are central to understanding ecological dynamics following large fires in southwestern forests. Moreover, simplistic assumptions regarding the relation of fire severity to fire size and climate should be viewed with caution.
4

Agricultura sintrópica: produzindo alimentos na floresta, das raízes do aipim ao dossel das castanheiras / Syntropic farming: Producing food in the forest, from the cassava roots to the canopy of the chestnut trees

Gregio, Josué Vicente 02 March 2018 (has links)
Submitted by Fabielle Cheuczuk (fabielle.cheuczuk@unioeste.br) on 2018-07-13T14:34:14Z No. of bitstreams: 2 Dissertação Josué Gregio final.pdf: 6668575 bytes, checksum: 2fd7e2c0fe85a18b7b1ad652fa6be17d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-07-13T14:34:14Z (GMT). No. of bitstreams: 2 Dissertação Josué Gregio final.pdf: 6668575 bytes, checksum: 2fd7e2c0fe85a18b7b1ad652fa6be17d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-02 / With the evolution of the genus Homo, both intellectually and physically, an important phase of history began: the Neolithic farming revolution. The planet came to know an activity that so far hadn’t been part of the relations between living beings: farming. Over the centuries the landscape has changed, along with the evolution of techniques to carry on such activity. The most affected environments were forest ecosystems, as the introduction of fire and cutting tools allowed the forest to be put down and burned for later agricultural planting. The advance of this management, along with the continuous increase of domesticated species, has provided the expansion of framing for great part of the world. In modern times, this activity has reached great proportions, influenced mainly by the green revolution, genetics, chemistry and biotechnology, that became widely present in the farming environment .Therefore, it is evident the degradation that this practice brings to life. As an attempt to confront this situation agroecology has been trying to rescue and improve practices that are well-adjusted to the dynamics of nature. When dealing with a science that involves many areas of knowledge, agroecology is based on working with the flow of life and natural processes. An activity that is related to agro ecological science is agroforestry systems, which basically has the purpose of forest restoration, food production and products for use in human daily life. However, in a more intense sense of the agroforestry system, there is an activity developed by the Swiss farmer / researcher Ernst Götsch, with his theory and practice has been developing for almost forty years the work of forest recovery and food production, called Syntropic Farming. So, the work aims to perform an analysis of the Syntropic Farming, considering its foundations and empirical applications. For the analysis of the empirical experiments, three areas were selected that follow the management proposed and developed by Götsch, located in the states of Bahia, Rio Grande do Sul and in the Federal District. In order to fulfill this objective, the research had different stages. Being carried out research and readings of bibliographical references; interviews; visitation to the selected areas, to acquire knowledge of the history and composition of the agroforestry systems in question and direct observation; implantation and evaluation of an agroforestry system in a town, called Sananduva - RS, in the property of the own author. The results indicate that the Syntropic Farming shows great potential for forest recovery, together with the restoration of the micro fauna due to the constant presence of organic matter in the soil. It is noteworthy the great production of food, both in quantity and in quality. The potential of replicability of the Syntropic Farming in the three analyzed experiences was also verified, considering some selected central aspects. Since the cultivation is based on the processes of the forest, an important effect is in the autonomy that the system provides to the farmer. / Com a evolução do gênero Homo, tanto intelectualmente quanto fisicamente, viu-se iniciar uma importante fase da história: a revolução agrícola neolítica. O planeta passou a conhecer uma atividade que até então não havia feito parte das relações entre os seres vivos: a agricultura. Com o passar dos séculos a paisagem foi mudando, juntamente com a evolução de técnicas para exercer tal atividade. Os ambientes mais atingidos foram os ecossistemas florestais, pois a introdução do fogo e ferramentas de corte permitiram que a floresta fosse posta abaixo e queimada, para posterior plantio agrícola. O avanço deste manejo, juntamente com o acréscimo contínuo de espécies domesticadas proporcionaram a expansão da agricultura por boa parte do mundo. Em tempos modernos, esta atividade atingiu grandes proporções, influenciada principalmente pela revolução verde, a genética, a química e a biotecnologia, que tornam-se onipresentes nos meios agrícolas. Para tanto, fica evidente a degradação que tal prática ocasiona à vida. Na tentativa de contrapor esta situação a agroecologia tem procurado resgatar e aperfeiçoar práticas mais equilibradas com a dinâmica da natureza. Tratando de uma ciência que envolve muitas áreas do conhecimento, a agroecologia tem por base trabalhar no fluxo da vida e dos processos naturais. Uma atividade que adentra a ciência agroecológica são os sistemas agroflorestais, que em grande parte tem a finalidade de recomposição florestal, produção de alimentos e produtos para uso no cotidiano humano. Porém, num sentido mais profundo de sistema agroflorestal, está a atividade desenvolvida pelo suíço agricultor/pesquisador Ernst Götsch, que com sua teoria e prática vem desenvolvendo, há quase quarenta anos, o trabalho de recuperação florestal e produção de alimentos, chamado de Agricultura Sintrópica. Para tanto, o trabalho objetiva realizar uma análise da Agricultura Sintrópica, considerando seus fundamentos e aplicações empíricas. Para a análise das experiências empíricas foram selecionadas três áreas que seguem o manejo proposto e desenvolvido por Götsch, localizadas no estado da Bahia, Rio Grande do Sul e no Distrito Federal. Para o cumprimento do referido objetivo, a pesquisa teve diferentes etapas, sendo realizadas pesquisa e leituras de referenciais bibliográficos; entrevistas; visitação às áreas selecionadas, para conhecimento da história e da composição dos sistemas agroflorestais em questão e observação direta; implantação e avaliação de um sistema agroflorestal no município de Sananduva – RS, em propriedade do próprio autor. Os resultados indicam que a Agricultura Sintrópica mostra grande potencial para recuperação florestal, juntamente com a restauração da microfauna, devido à presença constante de matéria orgânica no solo. Destacase a grande produção de alimentos, tanto em quantidade quanto em qualidade. Também, foi constatado o potencial de replicabilidade da Agricultura Sintrópica nas três experiências analisadas, considerando alguns aspectos centrais selecionados. Por se tratar de cultivo baseado nos processos da floresta, um efeito importante está na autonomia que o sistema proporciona ao agricultor.
5

Functional Trait Based Community Assembly in a Secondary Tropical Dry Forest (熱帯乾燥地の二次林における機能形質に基づいた群集形成) / 熱帯乾燥地の二次林における機能形質に基づいた群集形成

Bo, Sann 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20443号 / 農博第2228号 / 新制||農||1050(附属図書館) / 学位論文||H29||N5064(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 神﨑 護, 教授 北島 薫, 教授 大澤 晃 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
6

Potential Forest Regeneration in Western New York State Green Ash Stands Depleted by Emerald Ash Borer Invasion

Coupland, Abagail L. 07 August 2023 (has links)
No description available.
7

Three essays on Brazil's deforestation control policies and their potential effects: Conflicts, Compliance, and Secondary forest recovery

Shinde, Nilesh Nivrutti 02 September 2022 (has links)
Brazil reduced its annual deforested area from 27772 km2 to 4571 km2 from 2004 to 2012. This phenomenal achievement resulted from multiple government initiatives, most notably the Action Plan for the Prevention and Control of Deforestation in the Legal Amazon (PPCDAm). However, these ambitious deforestation control policies yield multiple spillover effects. This dissertation examines the effects of the two initiatives from the PPCDAm program, namely the Forest Code of 2012 and the Green Municipality Program. The first chapter provides causal evidence that land registration abates conflicts in Pará. The chapter discusses policy implications in three discussions, prospective deforestation control, potential agricultural growth, and livelihoods promotion within CAR and its related policies. The results from this chapter provoke a question about the drop in land conflicts that stimulates forest conservation on private landholdings. Thereon, my second chapter deals with the dynamic land clearing decision of private landholders in the Brazilian Amazon. The results suggest that the persistence of compliance, thus forest conservation on privately held land, is driven mainly by past compliance and municipality-level incentives. As these two chapters established that land registration abates conflicts, and private landholders are driven by specific incentives to preserve the forest on their land. My third chapter investigates the impact of the provincial governance promotion program on secondary forest recovery. Municipalities participating in the local government improvement program steadily observe an expansion in secondary forest areas. To sum up, my dissertation explores the spillover effects of the deforestation control policy, starting with achieving fewer land conflicts and investigating the local incentives to promote forest protection on private land. Lastly, I provide evidence that the governance promotion program will result in secondary forest recovery. / Doctor of Philosophy / Brazil reduced its annual deforested area from 27772 km2 to 4571 km2 from 2004 to 2012. This phenomenal achievement resulted from multiple government initiatives, most notably the Action Plan for the Prevention and Control of Deforestation in the Legal Amazon (PPCDAm). This dissertation presents the unintended consequences of two policies under PPCDAm, namely the Forest Code of 2012 and the Green Municipality Program, on land conflicts, environmental policy compliance, and secondary forest recovery. The first chapter provides robust evidence that perceived land tenure security (via land registration) effectively reduces land conflicts. Further, the chapter invokes if the drop in land conflicts stimulates forest conservation on private landholdings. Subsequently, my second chapter deals with the dynamic land clearing decision of private landholders in the Brazilian Amazon. The results suggest that the persistence of compliance, thus forest conservation on privately held land, is driven mainly by past compliance and municipality-level incentives. As these two chapters established that land registration abates conflicts, and private landholders are driven by specific incentives to preserve the forest on their land. My third chapter investigates the impact of the provincial governance promotion program on secondary forest recovery. Municipalities participating in the local government improvement program steadily observe an expansion in secondary forest areas. In summary, the dissertation begins with a study of the unintended consequences of the deforestation control policy, starting with achieving fewer land conflicts. Then, I present a study of the local incentives to promote forest protection on private land. Lastly, I present that the local governance promotion program will result in secondary forest recovery.
8

Transição Florestal no estado de São Paulo, Brasil: fatores associados ao desmatamento e recuperação das matas nativas / The forest transition in São Paulo, Brazil: drivers related to forest loss and recovery

Calaboni, Adriane 09 June 2017 (has links)
Segundo a Teoria da Transição Florestal, países menos desenvolvidos teriam altas taxas de desmatamento, pois a economia destes países é baseada no desenvolvimento e expansão agrícola. Com o avanço do desenvolvimento econômico a industrialização, urbanização e a modernização do uso da terra levariam ao abandono de terras menos adequadas à agricultura que seriam ativamente reflorestadas ou regenerariam. Visto que São Paulo vem apresentando ganhos de cobertura florestal nativa, este estudo teve como objetivo principal identificar os fatores relacionados ao processo de transição florestal no estado de São Paulo entre 1960 e 2006. Para isso, o Capítulo 1 avaliou as discrepâncias entre três estimativas de cobertura florestal nativa disponíveis para o estado de São Paulo (censo agropecuário e dois mapeamentos com resolução de 10m e 30m), em escala municipal, e as possíveis fontes de viés associadas aos métodos de coleta. O Capítulo 2 identificou os fatores socioeconômicos e biofísicos associados ao desmatamento e à recuperação das florestas nativas nos municípios do estado de São Paulo em quatro períodos consecutivos (1960-1970, 1970-1980, 1980-1996, 1996-2006). Os resultados do Capítulo 1mostraram que o censo agropecuário subestima a cobertura florestal quando há áreas protegidas nos municípios. Mapas com resolução de 30m também subestimam a cobertura florestal nativa em relação aos mapas com 10m de resolução, visto que não detectam pequenos fragmentos. As três fontes de dados são congruentes, porém os vieses relacionados aos métodos podem refletir nos resultados. Logo, a escolha dos dados deve ser feita de acordo com os objetivos do estudo a ser desenvolvido e considerando os métodos de coleta e possíveis fontes de viés de cada conjunto de dados. O Capítulo 2 mostrou que as perdas de florestas ocorreram principalmente em municípios com solos mais úmidos e/ou naqueles em que houve expansão de cultivos. Enquanto ganhos de florestas ocorreram principalmente em municípios com maior cobertura florestal, maior declividade média, que empregaram maior número de trabalhadores permanentes e usaram mais fertilizantes. Estes resultados mostram que, entre 1960 e 2006, a expansão do uso da terra levou a perdas de florestas em áreas mais adequadas à agricultura de São Paulo. Com o tempo, porém, fatores que aumentam a produtividade ou reduzem a conversão de áreas naturais levaram ao aumento de florestas, principalmente em terras menos adequadas à agricultura. Tais fatores, no entanto, foram influenciados por políticas governamentais para modernização da agricultura e proteção dos ecossistemas naturais, e pela pressão do mercado externo por certificação ambiental. Estes resultados enfatizam a necessidade de se considerar, em conjunto, desenvolvimento da agricultura e conservação do meio ambiente para o desenvolvimento de políticas de uso da terra mais eficientes / According to Forest Transition Theory, less developed countries or regions present high rates of deforestation because their economy is based on agricultural development and agriculture expansion. As the economy develops industrialization, urbanization and agriculture modernization lead to the abandonment of lands less suitable for agriculture which are reforested or regenerate spontaneously. Since forest cover of São Paulo has increased, this study aimed to identify the socioeconomic and biophysical factors related to forest transition in the state of São Paulo between 1960 and 2006. For this purpose, Chapter 1 evaluate the discrepancies among three free datasets of São Paulo\'s forest cover (agricultural census, maps at 10m and 30m resolution), in municipality-scale, and the possible sources of bias. Chapter 2 identified the factors related to deforestation and forest gains in São Paulo\'s municipalities during four consecutive intervals (1960-1970, 1970-1980, 1980-1996, 1996-2006). Chapter 1 showed that census underestimate forest cover when legally protected areas are present, reflecting the limitation of survey methods in rural properties. Maps at 30m resolution also underestimate forest cover in comparison to maps at 10m resolution, since 30m resolution cannot detect small and narrow patches. The three datasets are congruent, but the results indicate that bias related to methods can affect analysis results. Therefore, users should choose a dataset according to aims of the study and considering the sources of bias in the data. Chapter 2 showed that forest losses were greater in municipalities with moist soils and large tracts of agricultural lands, while forest gains were higher in municipalities with high forest cover and steep slopes, and that employed a large number of permanent workers and relied on high fertilizer input. Between 1960 and 2006, land use expansion led to forest losses in more suitable areas for agriculture in São Paulo. Over time, factors that increase productivity or reduce pressure on land development led to forest gains mainly in less suitable lands. These proximate factors, however, were driven by underlying factors as governmental policies to modernize agriculture and protect natural ecosystems, and by external market demands for environmental certification. These results highlight the need to jointly consider agricultural development and environmental conservation policies for the development of effective land use policies
9

Análise de alguns aspectos de dinâmica florestal em uma área degradada no interior do parque estadual do Jurupará, Ibiúna, São Paulo. / Analysis of some aspects of forest dynamics in a degradated area inside the jurupará state park, Ibiúna, São Paulo state.

Souza, Silvana Cristina Pereira Muniz de 18 June 2002 (has links)
O presente trabalho teve como objetivo investigar a resiliência de uma área desflorestada há aproximadamente 20 anos, ocupada atualmente com pastagem e cultivo de Citrus sp. Essa resiliência foi avaliada através dos seguintes aspectos da dinâmica florestal: análise do banco de sementes, da chuva de sementes e de indivíduos jovens regenerantes. Este trabalho foi conduzido no Parque Estadual do Jurupará (23°51' S e 47°11' W), abrangendo os municípios paulistas de Ibiúna e Piedade, em uma região de transição entre a Floresta Ombrófila Densa e a Floresta Estacional Semidecidual. Foram alocadas três faixas de amostragem, cada uma com cinco parcelas aleatorizadas de 10 X 20 m, uma num trecho ocupado com um plantio abandonado de Citrus sp, adjacente ao remanescente florestal, e as restantes num trecho ocupado com pastagem, uma a 0-20 m e outra a 80-100 m de distância do remanescente florestal. Para a avaliação da chuva de sementes, foram lançados aleatoriamente em cada parcela três coletores de sementes circulares de 0,52 m de diâmetro, com coletas mensais das sementes depositadas. Para a avaliação do banco de sementes foram instalados em cada parcela, três subparcelas de 0,25 X 0,25 m, para coleta de solo até 0,05 m de profundidade em duas épocas distintas: estação chuvosa (janeiro/2001) e na estação seca (agosto/2001). Para a avaliação dos indivíduos jovens regenerantes, foram implantadas aleatoriamente 4 subparcelas de 0,5 X 0,5 m, nas quais foram realizadas três avaliações de todos os indivíduos arbustivos-arbóreos com altura entre 0,30 e 1,30 m. Na avaliação da chuva de sementes na área ocupada com o cultivo de Citrus sp, foi observada alta densidade de sementes autóctones de espécies arbustivo-arbóreas (Leandra sp. com 20.638,73 sem.m -2 e Tibouchina sp. com 12.681,85 sem.m -2 ) que ocupavam a área junto com aos indivíduos de Citrus sp. Na pastagem verificou-se a predominância de espécies ruderais, a densidade média das espécies arbustivo-arbóreas foi de 335,75 sem.m -2 , na pastagem próxima do remanescente florestal e de 577,58 sem.m -2 na pastagem distante do remanescente florestal. Na avaliação do banco de sementes no cultivo de Citrus sp, as espécies ruderais consistiram em 99,88% das espécies germinadas na estação chuvosa, e 99,73% na estação seca. Na pastagem, na estação chuvosa, para as duas distâncias, 100% das espécies germinadas eram espécies herbáceas tipicamente ruderais; na estação seca esta forma de vida predominou em 99,66% na área próxima ao remanescente florestal e 99,92% na área mais distante. No levantamento dos indivíduos jovens regenerantes, encontrou-se densidade 5,8 ind.m -2 na área de Citrus sp e de 1,2 ind.m -2 e 2,2 ind.m -2 na pastagem a 0-20 m e 80-100 m de distância do remanescente florestal, respectivamente. Apenas na chuva de sementes foram encontradas diferenças significativas entre a área de Citrus sp e a pastagem, para os demais aspectos analisados não foram encontradas diferenças significativas entre a área de Citrus sp e pastagem. Na pastagem, para todos os apectos analisados, não foram encontradas diferenças significativas entre as diferentes distâncias, rejeitando a hipótese de que a resiliência da pastagem estudada está inversamente relacionada com as distâncias do remanescente florestal nesse trabalho. / This work had as a goal identifying the resilience of an area, which was deforested in the past, currently used as pasture and Citrus sp crop. This resilience was evaluated through the following aspects of forest dynamics: soil seed bank analysis, seed rain and saplings. It was conducted in the Jurupará State Park in Ibiúna and Piedade (São Paulo State), in a transition area between the Ombrophil Forest and the Semideciduous Seasonal Forest. In this area, three sampling strips were allocated, each one with five 10 X 20 m plots, being one inside the Citrus sp crop and the others inside the pasture, distant 0-20 m and 80-100 m from the forest remant. For evaluating the seed rain, three circular seeds collectors of 0.52 cm in diameter were randomly set in each plot, with monthly samplings of the deposited seeds. For evaluating the seed bank, soil of three 0.25 X 0.25 m sub-plots and 0.05 m deep was collected in two different seasons: rainy season (January/2001) and dry season (August/2001). To the saplings evaluation, four 0.5 X 0.5 m sub-plots were implanted randomly, in which three evaluations of all the shrubs and trees individuals (0.30-1.30m height) were performed. At the seed rain inside the Citrus sp crop, a high density of autoctone seed of shrubs and trees species (Leandra sp. with 20,638.73 seed.m -2 and Tibouchina sp. with 12,681.85 seeds.m -2 ) was observed; inside the pasture, there were a predominance of ruderal species, while the average density of shrubs and trees species were, 335.75 seeds.m -2 in the pasture distant 0-20m from the remaining forest and 577.58 seeds.m -2 in the pasture distant 80-100m from the remaining forest. At the soil seed bank evaluation in the experimental area inside the Citrus sp crop, the ruderal species were 99.88% of the germinated species in the rainy season and 99.73% in the dry season. In the experimental area inside the pasture, for the rainy season, 100% of the germinated species were herbal species typically ruderal in both distances; in the soil collected in the dry season, this life form was predominant in 99.66% and 99.92% in both distances, respectively. In the saplings counting, a 5.8 ind.m -2 density inside was found the Citrus sp crop and 1.2 and 2.2 ind.m -2 inside the pasture in both distances. Only for the seeds rain significant differences were found between the Citrus sp crop and the pasture. No significant differences were found between the two distances within the pasture area strips, denying the hypothesis that the resilience of the study area is inversely related to the remaining forest distance.
10

Análise de alguns aspectos de dinâmica florestal em uma área degradada no interior do parque estadual do Jurupará, Ibiúna, São Paulo. / Analysis of some aspects of forest dynamics in a degradated area inside the jurupará state park, Ibiúna, São Paulo state.

Silvana Cristina Pereira Muniz de Souza 18 June 2002 (has links)
O presente trabalho teve como objetivo investigar a resiliência de uma área desflorestada há aproximadamente 20 anos, ocupada atualmente com pastagem e cultivo de Citrus sp. Essa resiliência foi avaliada através dos seguintes aspectos da dinâmica florestal: análise do banco de sementes, da chuva de sementes e de indivíduos jovens regenerantes. Este trabalho foi conduzido no Parque Estadual do Jurupará (23°51' S e 47°11' W), abrangendo os municípios paulistas de Ibiúna e Piedade, em uma região de transição entre a Floresta Ombrófila Densa e a Floresta Estacional Semidecidual. Foram alocadas três faixas de amostragem, cada uma com cinco parcelas aleatorizadas de 10 X 20 m, uma num trecho ocupado com um plantio abandonado de Citrus sp, adjacente ao remanescente florestal, e as restantes num trecho ocupado com pastagem, uma a 0-20 m e outra a 80-100 m de distância do remanescente florestal. Para a avaliação da chuva de sementes, foram lançados aleatoriamente em cada parcela três coletores de sementes circulares de 0,52 m de diâmetro, com coletas mensais das sementes depositadas. Para a avaliação do banco de sementes foram instalados em cada parcela, três subparcelas de 0,25 X 0,25 m, para coleta de solo até 0,05 m de profundidade em duas épocas distintas: estação chuvosa (janeiro/2001) e na estação seca (agosto/2001). Para a avaliação dos indivíduos jovens regenerantes, foram implantadas aleatoriamente 4 subparcelas de 0,5 X 0,5 m, nas quais foram realizadas três avaliações de todos os indivíduos arbustivos-arbóreos com altura entre 0,30 e 1,30 m. Na avaliação da chuva de sementes na área ocupada com o cultivo de Citrus sp, foi observada alta densidade de sementes autóctones de espécies arbustivo-arbóreas (Leandra sp. com 20.638,73 sem.m -2 e Tibouchina sp. com 12.681,85 sem.m -2 ) que ocupavam a área junto com aos indivíduos de Citrus sp. Na pastagem verificou-se a predominância de espécies ruderais, a densidade média das espécies arbustivo-arbóreas foi de 335,75 sem.m -2 , na pastagem próxima do remanescente florestal e de 577,58 sem.m -2 na pastagem distante do remanescente florestal. Na avaliação do banco de sementes no cultivo de Citrus sp, as espécies ruderais consistiram em 99,88% das espécies germinadas na estação chuvosa, e 99,73% na estação seca. Na pastagem, na estação chuvosa, para as duas distâncias, 100% das espécies germinadas eram espécies herbáceas tipicamente ruderais; na estação seca esta forma de vida predominou em 99,66% na área próxima ao remanescente florestal e 99,92% na área mais distante. No levantamento dos indivíduos jovens regenerantes, encontrou-se densidade 5,8 ind.m -2 na área de Citrus sp e de 1,2 ind.m -2 e 2,2 ind.m -2 na pastagem a 0-20 m e 80-100 m de distância do remanescente florestal, respectivamente. Apenas na chuva de sementes foram encontradas diferenças significativas entre a área de Citrus sp e a pastagem, para os demais aspectos analisados não foram encontradas diferenças significativas entre a área de Citrus sp e pastagem. Na pastagem, para todos os apectos analisados, não foram encontradas diferenças significativas entre as diferentes distâncias, rejeitando a hipótese de que a resiliência da pastagem estudada está inversamente relacionada com as distâncias do remanescente florestal nesse trabalho. / This work had as a goal identifying the resilience of an area, which was deforested in the past, currently used as pasture and Citrus sp crop. This resilience was evaluated through the following aspects of forest dynamics: soil seed bank analysis, seed rain and saplings. It was conducted in the Jurupará State Park in Ibiúna and Piedade (São Paulo State), in a transition area between the Ombrophil Forest and the Semideciduous Seasonal Forest. In this area, three sampling strips were allocated, each one with five 10 X 20 m plots, being one inside the Citrus sp crop and the others inside the pasture, distant 0-20 m and 80-100 m from the forest remant. For evaluating the seed rain, three circular seeds collectors of 0.52 cm in diameter were randomly set in each plot, with monthly samplings of the deposited seeds. For evaluating the seed bank, soil of three 0.25 X 0.25 m sub-plots and 0.05 m deep was collected in two different seasons: rainy season (January/2001) and dry season (August/2001). To the saplings evaluation, four 0.5 X 0.5 m sub-plots were implanted randomly, in which three evaluations of all the shrubs and trees individuals (0.30-1.30m height) were performed. At the seed rain inside the Citrus sp crop, a high density of autoctone seed of shrubs and trees species (Leandra sp. with 20,638.73 seed.m -2 and Tibouchina sp. with 12,681.85 seeds.m -2 ) was observed; inside the pasture, there were a predominance of ruderal species, while the average density of shrubs and trees species were, 335.75 seeds.m -2 in the pasture distant 0-20m from the remaining forest and 577.58 seeds.m -2 in the pasture distant 80-100m from the remaining forest. At the soil seed bank evaluation in the experimental area inside the Citrus sp crop, the ruderal species were 99.88% of the germinated species in the rainy season and 99.73% in the dry season. In the experimental area inside the pasture, for the rainy season, 100% of the germinated species were herbal species typically ruderal in both distances; in the soil collected in the dry season, this life form was predominant in 99.66% and 99.92% in both distances, respectively. In the saplings counting, a 5.8 ind.m -2 density inside was found the Citrus sp crop and 1.2 and 2.2 ind.m -2 inside the pasture in both distances. Only for the seeds rain significant differences were found between the Citrus sp crop and the pasture. No significant differences were found between the two distances within the pasture area strips, denying the hypothesis that the resilience of the study area is inversely related to the remaining forest distance.

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