Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As florestas tropicais amazônicas são um importante reservatório de carbono acima e abaixo do solo. Elas desempenham uma importante função tanto no sequestro do carbono atmosférico quanto no armazenamento desse carbono em forma de biomassa. O objetivo desse trabalho foi quantificar a variação espacial da biomassa arbórea viva e avaliar o efeito de variáveis climáticas e ambientais ao longo de cerca de 400 km de florestas alagadas no médio e baixo rio Branco. Especificamente, foi avaliado o efeito (i) da duração da inundação, (ii) do comprimento da estação seca e (iii) da textura e fertilidade do solo no estoque de biomassa acima do solo. Foram amostrados 2.432 indivíduos com Diâmetro à altura do Peito (DAP) ≥ 10 cm, distribuídos em 54 parcelas compridas (250 metros) e estreitas (4 metros) de 0,1 ha. Para cada indivíduo amostrado, além do DAP, foram determinadas a altura total e a densidade da madeira. A biomassa viva acima do solo das árvores foi estimada através da média de três modelos alométricos que consideram DAP, densidade da madeira e altura das árvores. A biomassa de palmeiras foi estimada com base em um único modelo que considera apenas a altura dos indivíduos. A biomassa variou de 21,5 a 245,15 Mg/ha. Não foi observada relação entre a biomassa e as variáveis climáticas (precipitação média anual e comprimento da estação seca). As variáveis ambientais: solo (% de argila) e a duração da inundação também não explicaram a variação da biomassa arbórea viva acima do solo nas florestas alagadas do rio Branco. Estes resultados representam as primeiras estimativas de biomassa arbórea para as florestas alagadas do rio Branco. A grande variação observada entre as parcelas sugere que eventos estocásticos locais, a estrutura da floresta e a composição florística podem ser mais importantes para explicar a variação da biomassa do que fatores climáticos e características do solo. / Amazonian forests are an important above and belowground carbon reservoir. They play an important role in both the sequestration of atmospheric carbon and storage of carbon as biomass. The aim of this study was to quantify the spatial variation of above ground tree live biomass and evaluate the effects of climatic and environmental predictors along ~400km of flooded forests in the middle and lower rio Branco (Roraima). Specifically, I related plot-based biomass estimates with (i) duration of flooding, (ii) length of the dry season, and (iii) texture and fertility of the soil. A total of 2.432 individuals with diameter at breast height (DBH) ≥ 10 cm where sampled in 54 long (250 meters) and narrow (4 meters) plots of 0.1 hectare. For each individual sampled, were also determined: total tree height and wood density. The above ground live biomass of trees was estimated by the average of three allometric models that consider DBH, wood density, and tree height. Palm biomass was estimated based on a single model that considers only the height of individuals. Biomass estimates presented a 10-fold variation, ranging from 21.5 to 245.15 Mg/ha. No relationship between biomass and climatic variables (mean annual rainfall and length of dry season) were observed. Environmental variables: soil (% clay) and the duration of the flood also did not explain the variation in tree biomass in the flooded forests of the rio Branco. These represent the first tree biomass estimates for the flooded forests of the rio Branco, and the large biomass variation observed in the plots suggest that local stochastic events, forest structure and floristic composition may be more important in explaining biomass variation than climatic and soil factors.

Foi realizado levantamento quanti-qualitativo de vegetais de porte arbóreo em dois bairros paulistanos, Vila Vera e Jardim da Saúde, situados na região sudeste de São Paulo, não distando muito entre si, porém com características de ocupação de uso de solo bastante distintas. No Jardim da Saúde foram encontrados 1033 exemplares de 72 espécies botânicas, a altura média de todas as árvores foi de 8,07 m e a altura da primeira bifurcação 1,97 m, a Caesalpinea peltophoroides Benth. foi a espécie mais freqüente com 20,68%, seguida da Lagestroemia indica L. com 7,48% e da Ligustrum lucidum W.T. Aiton em terceiro com 6,89%, essas três espécies somaram 35,05% dos indivíduos. Existiam 80,45% dos exemplares situados defronte a imóveis que possuíam recuo mínimo de 2,50 m de construções, 72,80% do total estavam em passeios que têm entre 1,00 m e 2,00 m, predominam árvores com mais de 8,50 m de altura, o pior indicador de sanidade vegetal seria a infestação de cupins com 8,33% do total infestado, 13,65% teve anotações de má qualidade de copa, 20,62% apresentou algum indicativo de má qualidade de tronco. Apenas 23,33% tinham situações de permeabilidade do passeio suficiente, encontravam-se 5,71% com condução de poda para desobstrução das redes aéreas, o rebaixamento das árvores acontecia em 7,74% dos exemplares. Na Vila Vera havia limitações de espaço físico não apenas das larguras dos passeios, mas principalmente do uso predominante dos lotes. As residências normalmente tomam todo o espaço da testada do imóvel com rebaixamento de guias para permitir a entrada veículos na garagem localizada defronte a construção. Encontraram-se 178 árvores pertencentes a 42 espécies botânicas, a média da altura total é de 6,31 m, e a média da primeira bifurcação 1,81 m. A espécie mais abundante foi a Caesalpinea peltophoroides Benth.com 24,71%, a segunda seria a Ligustrum lucidum W.T. Aiton com 17,24% do total, vindo em terceiro Lagerstroemia indica L. com 8,62%. Neste bairro existiam 71,35% das situações afastamento predial superior a 2,50 m, 42,70% com altura inferior a 4,50 m de altura, a sanidade vegetal estaria comprometida em 12,37% dos exemplares pela infestação de cupins, 55,62% estva localizada em passeios que variam sua largura entre 1,00 e 2,00 m, 50,00% apresentavam maus indicadores de qualidade de copa, 25,44% apresentou algum indicativo de má qualidade de tronco. Somente 7,87% do total de árvores estavam em situações de permeabilidade do passeio suficiente, os exemplares pavimentados até o tronco totalizavam 16,85%, as conduções de poda para desobstrução de redes eram 3,38% e as podas de rebaixamento 13,48%. Havia uma média de 16,85 m de afastamento entre árvores no Jardim da Saúde, sendo que na Vila Vera este indicativo era 38,68 m, portanto o afastamento médio da Vila Vera seria 2,29, na média do bairro, maior do que o existente no Jardim da Saúde. Em praticamente a totalidade dos indicativos qualitativos o Jardim da Saúde apresentava melhores avaliações das encontradas na Vila Vera, havendo neste segundo local, maiores impedimentos ao adensamento de plantios em função das características do espaço existente. / An tree qualitative and quantitative study was conducted in two closely located neighborhoods (Vila Vera and Jardim da Saude) in the southeast region of São Paulo. In spite of geographical vicinity, both neighborhoods have very different land occupation characteristics. In Jardim da Saude we found 1033 tree specimens, belonging to 72 distinct botanic species, with an average height of 8,07m and average first bifurcation height of 1.97m. Caesalpinea peltophoroides Benth was the most frequent species found (20,68% of the trees), followed by Lagestroemia indica L. (with 7,48% of the trees), and Legustrum lucidum W.T. Aiton coming in third place (with 6,89% of the trees). Those three species together account for 35.05% of the specimens. 72.80% are located in sidewalks that are between 1.00m and 2.00 m wide. Most trees have a height of 8,50 m and above. The worst health threat was termite infestation which affected 8.33% of the specimens. 13.65% were noted to have poor crown quality, 20.62% presented some indication of poor trunk quality and only 23.33% of the trees where planted in an area which enough surface permeability. 5.71% of the specimens had been pruned to prevent interference with electrical lines and crown-reducing pruning had been done in 7.74% of the trees. In Vila Vera we found limited space conditions in regards to the width of the sidewalk and also in regards to the predominant type of site utilization. Residential buildings constructions usually advance far into the sidewalk, with a driveway for access to the garages which are usually located in the front side of the building. We counted 178 trees belonging to 42 distinct botanic species, with average height of 6.31m and first bifurcation average height of 1.81m. The most common species is Caesalpinea peltophoroides Benth. (Which accounted for 24.71% of the specimens), followed by a Legustrum lucidum W.T. Aiton (with 17.24%) and Lagerstroemia indica L. in third place (with 8.62%). In this neighborhood 42.70% of the trees had a height of less than 4.5m, 12.37% were in poor health due to termite infestation, 55.62% are located in sidewalks with widths varying between 1.00 and 2.00 m, 50.0% displayed poor crown quality and 25,44% presented some indication of poor trunk quality. Only 7.87% of the specimens where planted in an area which enough surface permeability, while 16.85% where located in totally paved areas. 3.38% had been pruned to avoid interference with electrical lines and 13.48% had been crown-reducing pruned. In Jardim da Saude the average distance between trees was 16.85m, while in Vila Vera it was 38.68m. In other words, the average distance between trees is about 2.29 greater in Vila Vera than in Jardim da Saude.. Practically all the qualitative domains were found to be superior for Jardim da Saude. Vila Vera also presents greater impediments for increasing planting density due to its current space availability issues.

Old and coarse trees implement vital functions for humans, animals, and nature. Swedish forests have for a long time been affected by man, which affects the trees’ age and size distribution. The proportion of old-trees is currently low and it is desirable to increase it. Using data on sample trees’ from the Swedish National Forest Inventory, I analysed old-tree distribution in different land-use types and age-distribution, as well as coarse trees in Östergötland under the years 1983-2017. Furthermore, I analysed the sample trees form the year 1927 to compare with the sample trees in period 1983-2017. The defined age of an old-tree 5% older trees in the data was used while the coarse trees were defined by “miljömålets” definition. The tree sample data involved Pinus sylvestris, Picea abies, Quercus robur, Populus tremula, and Alnus glutinosa. Their occurrence in four different land-use types were considered: (i) productive woodland, (ii) arable land and natural pasture, (iii) mountains and other wastelands, and (iv) peatland. The results shows that a higher percentage of old and coarse trees occur in (i) productive woodland during the years 1983-2017. The coarse trees had similar distribution in the different land-use types during the years 1983-2017 and over time. Comparison with 1927 showed that the number of old-trees has decreased while the coarse trees had increased. Thus, the land-use types, except (i), do not constitute a reservoir for old and coarse trees and that the coarse trees individuals overlap with the old trees. / Gamla träd och grova träd utför livsviktiga funktioner för både människa, djur och natur. Sveriges skogar har länge påverkats av människan och det har påverkat trädens ålders- och storleksfördelning. Idag är andelen gamla träd låg i Sverige och det manifesteras åtgärder för att öka andelen äldre och grövre träd i skogarna. Genom att använda riksskogstaxeringens provträdsdata kan vi veta hur gamla och grova träd är fördelade bland marktyper. Denna studie undersökte hur gamla provträd var fördelade bland marktyper och deras åldersfördelning, samt motsvarande för grova träd i Östergötlands län. Dessutom jämfördes perioderna 1983–2017 och 1927. Gamla träd utgjorde per definition 5% av de äldre träden, medan grova träd definierades utifrån miljömålet levande skogar. Provträdsdata var på trädslagen; Pinus sylvestris, Picea abies, Quercus robur, Populus tremula och Alnus glutinosa som fanns inom marktyperna; (i) produktiv skogsmark, (ii) åkermark och naturbete, (iii) berg och vissa andra impediment, och (iv) myr. Resultaten visar att en hög andel gamla liksom grova provträd fanns inom produktiv skogsmark i Östergötlands län under 1983–2017. Bland marktyperna hade de grova provträd liknande odds och en liknande grovleksfördelning för båda perioderna. Dock sedan 1927 har andelen gamla träd minskat, medan andelen grova provträd har ökat. Därmed utgör marktyperna utöver (i) inte en reservoar för gamla som grova träd samt att de grova träden kan spegla de gamla trädens förekomst.

This study involved a dendrochronological examination of oak (Qeurcus.sp) and Scots pine (Pinus.sylvestris) in the nationalpark Blå Jungfrun, by measuring annual ringwidth data from tree-cores from the island, data from the national forest inventory and climatedata from the Swedish Meteorological and Hydrological Institute (SMHI). Using the analysis program Windendro an annual ringwidth analysis was performed. Trends that occured were that pine respondend more to precipitation than temperature and that oak respondend more to temperature. Ringwidth were higher for Scots pine than oak and for both species lower than on the mainland.

The Image-based Change Estimation program (ICE) was developed by the US Forest Service Forest Inventory & Analysis (FIA) program and the Geospatial Technology Applications Center in response to the 2014 Farm Bill calling for more timely and accurate estimates of land cover and use change. ICE monitors change throughout the US on a state by state basis by assessing each FIA plot using high resolution imagery from two dates in time. In the western US, FIA measures 10% of the plots each year to report on status, trends, and sustainability of our Nation’s forests. However, this 10 year cycle misses disturbances because a temporal gap occurs from disturbance event to measurement. This study compares field- and image-based observations of land cover and use change to improve sampling procedures in Utah. Image-based data collected from 2011 and 2014 imagery and field-based plots measured between 2011 and 2016 are compared using three methods to compile the ICE data, termed hierarchical, majority, and point center, to determine a standardized system and better understand their relationships. Additionally, ICE change agents were compared with causes of tree mortality observed on FIA forest plots to assess how well ICE evaluates causes of change and the differences of change vs. mortality agents were explored by conducting a second review of the imagery to find trends in data discrepancies. This knowledge can help image interpreters better recognize and identify change.

In the past 15 years, a large amount of public-domain lidar data has been collected over the Southeastern United States. Most of these acquisitions were undertaken by government agencies, primarily for non-forestry purposes. That is, they were collected mostly to aid in the creation of digital terrain models and to support hydrological and engineering assessments. Such data is not ideal for forestry purposes mainly due to the low pulse density per square meter, the high scan angles and low swath overlaps associated with these acquisitions. Nevertheless, the large area of coverage involved motivated this work. In this dissertation, I first look at how such lidar data (from non-forestry acquisitions) can be combined with National Forest Inventory tree height data to generate a large-area canopy height model. A simple linear regression model was developed using two lidar-based metrics as predictors: the 85th percentile of heights of canopy first returns and the coefficient of variation of the heights of canopy first returns. This model had good predictive ability over 76 disparate lidar projects, covering an area of approximately 297,000 square kilometers between them. Factors leading to the residual lack-of-fit of the model were also analyzed and quantified. For example, predictive ability was found to be better for softwood forests, forests with more homogeneous vegetation structure and for terrains with gentler slopes. Given that as much as 30% of the US is covered by public domain non-forestry lidar acquisitions, this is a first step for constructing a national wall-to-wall vertical vegetation structure map, which can then be used to ask important questions regarding forest inventories, carbon sequestration, wildlife habitat suitability and fire risk mitigation. Then, I examined whether such lidar data could be further used to predict understory shrub presence over disparate forest types. The predictability of classification model was low (accuracy = 62%, kappa = 0.23). Canopy occlusion factors and the heterogeneity of the understory layer were implicated as the main reasons for this poor performance. An analysis of the metrics chosen by the modeling framework highlighted the importance of non-understory metrics (metrics related to canopy openness and topographic aspect) in influencing shrub presence. As the proposed set of metrics were developed over a wide range of temperate forest types and topographic conditions of Southeastern US, it is expected that it will be useful for more localized future studies. Lastly, I explored the possibility of combining lidar-derived canopy height maps with Landsat-derived stand-age maps to predict plantation pine site index over large areas (site index is a measure of forest productivity). The model performance was assessed using a Monte Carlo technique (RMSE = 3.8 meters, relative RMSE = 19%). A sample site index map for large areas of Virginia and South Carolina was generated (map coverage area: 832 sq. km) and implications were discussed. Analysis of the resulting map revealed the following: (1) there is an increase in site index in most areas, compared to the 1970s, and (2) approximately 83% of the area surveyed had low levels of productivity (defined as site index < 22.0 meters for base age of 25 years). This work highlights the efficacy of combining lidar-based canopy height maps with other similar remote sensing based datasets to understand aspects of forest productivity over large areas, and to help make policy-relevant recommendations. / Ph. D.

This doctoral thesis investigates the potential of classification methods based on spatial context to infer specific forms of land use from remote sensing data. The problem is that some types of land use are characterized by a complex configuration of land covers that traditional per-pixel based methods have problems classifying due to spectral heterogeneity. The problem of spectral heterogeneity is also present in classification of high resolution imagery. Two novel methods based on contextual information are evaluated, Spatial Relational Post-Classification (SRPC) and Window Independent Context Segmentation (WICS). The thesis includes six case studies in rural and urban areas focusing on the classification of: agricultural systems, urban characteristics, and dead wood areas. In the rural case studies specific types of agricultural systems associated with different household strategies are mapped by inferring the physical expression of land use using the SRPC method. The urban remote sensing studies demonstrate how the WICS method is able to extract information corresponding to different phases of development. Additionally, different urban classes are shown to correspond to different socioeconomic profiles, demonstrating how urban remote sensing can be used to make a connection between the physical environment and the social lives of residents. Finally, in one study the WICS method is used to successfully classify dead trees from high resolution imagery. Taken together these studies demonstrate how approaches based on spatial context can be used to extract information on land use in rural and urban environments where land use manifests itself in the form of complex spectral class and land cover patterns. The thesis, thus, contributes to the research field by showing that contextual methods can capture multifaceted patterns that can be linked to land use. This, in turn, enables an increased use of remote sensing data, particularly in the social sciences. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript. Paper 5: Manuscript. Paper 6: Manuscript.</p>

In recent decades, political scientists have devoted substantial attention to the changing role of the state towards more inclusion of non-state actors in policymaking. This deliberative turn, or move towards governance, may signal inability to handle complex problems without cooperation with nonstate actors. On the other hand, governance is frequently credited with generating legitimate decision-making processes and results. In some instances, non-governmental actors have even taken the lead in policymaking. One archetype of such private governance, which has received significant scholarly attention, is forest certification. The Forest Stewardship Council (FSC) is frequently described as the most democratic and therefore legitimate forest certification organization since it grants equal voting rights to three stakeholder groups in the formulation of criteria for responsible forestry: environmental non-governmental organizations (ENGOs), social groups (indigenous peoples and labor organizations) and forest owners. However, in Sweden, a country often described as a role model in forest certification, the FSC has increasingly received critique for failing to generate legitimate processes and results, and recently three of five ENGOs have chosen to exit the FSC organization. Such processes of de-legitimation have received little attention in the forest certification literature. This thesis therefore provides a critical assessment of the legitimacy of forest certification in Sweden. Legitimacy is analyzed through concerned stakeholders’ perceptions of both procedural qualities (input legitimacy) and problem-solving capacity (output legitimacy). This study of legitimacy is combined with an assessment of the ability of certification to enhance environmental protection, defined as changes in both forest management practices and biophysical conditions. The thesis focuses not the least on legitimacy on the local level, which is where the actual implementation takes place. Today local studies of the legitimacy of forest certification are rare. Both quantitative and qualitative research methods are applied and a number of sources are analyzed: forest monitoring data, survey data, interviews with and documents produced by the participating stakeholders. Papers I and IV analyze the perceived legitimacy of forest certification, while Papers II and III analyze forest certification schemes’ ability to enhance environmental protection. The results show that a process of de-legitimation is occurring in Swedish forest certification. In particular, certification has lost legitimacy with ENGOs, which increasingly consider Swedish forest certification to lack both input legitimacy and output legitimacy. Moreover, although the Swedish FSC standard pays attention to reindeer husbandry, the results show that reindeer herders consider themselves to have limited power to influence long-term forest planning and management (low output legitimacy). The forest industry, on the other hand, increasingly grants legitimacy to forest certification due to customer demands, which are created not the least by pressures from international ENGOs and by EU regulation. The results also show that Swedish forest companies have paid more attention to their environmental practices after obtaining certification. However, to what extent these changes result in positive environmental impacts remains uncertain, especially since forests in Sweden grow slowly, which requires analyses over time. There are also measurement problems resulting from the low certification rate among small-scale forest owners and from the fact that certified small-scale owners tend to be more active in their management. These findings highlight that research on private forest governance should not neglect the role of the state, neither as a buyer nor as a regulator. These findings also suggest that further research should pay attention to power asymmetries in private governance and develop methods for better understanding and evaluating the certification schemes’ environmental and social impacts.

Apesar de ocupar cerca de 25% do território nacional e abrigar, potencialmente, um terço da fauna e flora brasileira, o bioma cerrado é classificado como um “hotspot" por apresentar expressiva redução de biodiversidade. Perante este quadro, este trabalho teve por objetivo comparar os métodos de amostragem de parcelas de área fixa e de ponto quadrante em uma área com predominância da fisionomia cerradão (savana florestada) na Estação Ecológica de Assis (SP), estando inserido no projeto temático “Métodos de Inventário da Biodiversidade de Espécies Arbóreas\", do Programa BIOTA/FAPESP. A área estudada é representada por uma grade amostral sistemática que contém 64 parcelas de 90 x 10 m (900 m2), inseridas em 8 linhas distantes 100 m entre si, com 8 parcelas em cada linha. Estas foram subdivididas em 9 subparcelas de 10 x 10 m, com um intervalo de 10 m não amostrado entre as parcelas nas linhas. Os pontos quadrantes foram instalados em cada limite entre as subparcelas. Os indivíduos arbóreos com DAP maior ou igual a 4,77 cm foram inseridos nesta amostragem, sendo posteriormente identificados. Partindo-se deste delineamento amostral e, diante da ocorrência de fragmentos de cerrado strictu sensu juntamente com áreas de cerradão, simulou-se a existência de nove tamanhos de parcela, variando de 100 a 900 m2, a fim de avaliar como esses diferentes tamanhos, bem como o método do ponto quadrante, interferem no esforço amostral, na estimativa da densidade e nos índices fitossociológicos e de diversidade. Ao final do levantamento, o método de parcelas de 900 m2 incluiu 102 espécies, distribuídas em 45 famílias, enquanto que o método do ponto quadrante amostrou 71 espécies, distribuídas em 37 famílias. Os resultados encontrados em ambos os métodos quanto ao Índice de Valor de Importância apontaram as espécies Copaifera langsdorffii, Vochysia tucanorum e Ocotea corymbosa como as mais importantes; já a família Myrtaceae se destacou nestes dois métodos quanto à riqueza de espécies. A curva de esforço amostral do método do ponto quadrante incluiu um número de espécies semelhante à curva das parcelas de 200 m2, com a vantagem de apresentar maior praticidade de instalação no campo. Os valores do Índice de Diversidade de Shannon foram inferiores a outros biomas, enquanto que o Índice de Diversidade de Simpson não pôde ser o mais indicado para o cerradão estudado, por não ser sensível à ocorrência de espécies com apenas um indivíduo na parcela. Para a determinação da diversidade arbórea do cerradão da E. E. Assis, recomendou-se o uso da parcela de 400 m2. Já na estimativa da densidade, as parcelas de 700 m2 foram as mais adequadas; entretanto, devido à grande variabilidade deste parâmetro na área, sugeriu-se uma estratificação da área de amostragem. / Cerrado biome is classified as a hotspot, because it presents an expressive reduction on the biodiversity, despite of occupying around 25% of the national territory and potentially sheltering one third of the Brazilian fauna and flora. In this scenario, this work had as objective to compare the fixed area plots and the point-centered quarter sampling methods in an area with a cerradão (savanna woodland) physiognomy at the Ecological Study Station in the city of Assis (SP), which is part of the “Tree Species Biodiversity Inventory Methods", a thematic project of BIOTA/FAPESP Program. The studied area is represented by a systematic sampling frame containing 64 plots, measuring 90 x 10 m (900 m2), inserted in 8 lines, which is 100 m away from each other, with 8 plots in each line. They were divided into 9 sub-plots measuring 10 x 10 m, with a 10-m non-sampled gap between the plots in the lines. The point-centered points were installed in each limit between the sub-plots. The arboreal individuals with DBH equal or larger than 4.77 cm were set in this sampling and identified later. From this sampling design and due to the presence of fragments of cerrado strictu sensu together with areas of cerradão, it was simulated the existence of nine size samples varying from 100 to 900 m2 aiming evaluating how these different sizes and the point-centered quarter method interfere in the sampling effort, in the density estimates, and in the phytossociological and diversity indexes. At the end of the surveying, the 900-m2-plot method included 102 species, distributed in 45 families, whereas in the center-pointed quarter method 71 species were sampled, distributed in 37 families. The results found in both methods in relation to the Importance Value Index showed Copaifera langsdorffii, Vochysia tucanorum, and Ocotea corymbosa as the most important ones; Myrtaceae family stood out on both methods in relation to species richness. The sampling effort curve of the point-center quarter method included a number of species similar to the 200-m2 plots’ curve, with an advantage of being easier to be installed in the field. The Shannon Index values were lower than in the other biomes, whereas the Simpson Index could not be the best indicated for the cerradão under study, because it was not sensitive to the presence of species with only one individual in the plot. It was recommended the use of 400-m2 plots in order to determine the tree diversity in the cerradão at the Ecological Study Station in the city of Assis. The most adequate plots to estimate the density were the 700-m2 ones. However, stratification on the sampling area was suggested due to the great variability of this parameter in the area.

Devido a atual situação de degradação da vegetação remanescente do estado de São Paulo, existe com relativa urgência uma grande necessidade de estudos que apoiem práticas de monitoramento e conservação dos fragmentos florestais para melhor gerenciá-los. Parte destas demandas é referente ao campo de amostragem, um conjunto de técnicas específicas para pesquisas ecológicas, onde a unidade amostral (parcela) é um dos fatores determinantes de sua eficiência. O objetivo deste estudo foi definir e propor o tamanho ideal de parcelas para otimizar o inventário florestal de áreas remanescentes de Floresta Estacional Semidecidual (FES) e de Cerrado (CER), assim como também de Floresta Estacional Semidecidual em processo de regeneração (FESreg). O trabalho foi realizado na Estação Experimental de Ciências Florestais de Itatinga - SP (EECFI/ESALQ/USP), visando à otimização da amostragem para as variáveis diâmetro à altura do peito (DAP), altura total, densidade populacional, área basal, volume total, volume de fuste, volume de galho, biomassa e índices de Shannon, de Simpson e de Riqueza. O delineamento experimental foi realizado com o auxílio de uma grade amostral, na qual foram distribuídas aleatoriamente 15 parcelas de 1.000 m2 cada, sendo cinco repetições em cada uma das três fisionomias florestais estudadas, onde todos os indivíduos com circunferência à altura do peito (CAP) acima de 16 cm foram mensurados e identificados. Cada unidade amostral foi divida em 10 subparcelas, permitindo assim avaliar os tamanhos de 100 m2 (10X10 m), 200 m2 (10x20 m), 300 m2 (10x30 m), 400 m2 (10x40 m e 20x20 m), 500 m2 (10x50 m), 600 m2 (20x30 m), 800 m2 (20x40 m) e 1.000 m2 (20x50 m). Os tratamentos (tamanhos) foram analisados através de análise de variância, métodos da curvatura máxima e esforço amostral. Com base nos resultados, recomenda-se respectivamente para Cerrado, Floresta Estacional Semidecidual e Floresta Estacional Semidecidual em regeneração o uso de parcelas de 200 m2, 200 m2 e 600 m2 para estimar qualquer uma das variáveis dendrométricas ou parcelas de 200 m2 para estimativas apenas de diversidade. Esses resultados são bastante úteis por embasarem uma série de pesquisas ambientais, deste modo, aperfeiçoando operações de inventário florestal para que o processo de amostragem não tenha esforço amostral desnecessário sem prejuízo da precisão. / Because of advanced status of degradation of the natural forest of the state of São Paulo, there is a relatively urgent need for the conduction of studies to support monitoring and conservation practices of forest fragments for their better management. Of these needs refers to sampling, with the use specific techniques for ecological research, in which characteristics of the sampling unit is of outmost importance. The objective of this study was to define and propose optimal plot sizes for inventories remnant areas of Semideciduous Forest (FES) and Cerrado (CER), as well as of Semideciduous forest in regeneration process (FESreg). The study was conducted at Estação Experimental de Ciências Florestais de Itatinga - SP (EECFI/ESALQ/USP), aiming to optimize the sampling for the variables diameter at breast height (DBH), total height, density, basal area, wood volume, volume of stem, branch volume, biomass as well as Shannon, Simpson and Richness indexes. The experiment was carried out with the aid of a sampling grid, in which 15 sampling units of 1,000 m2 each were randomly determined, with five replicates in each type of forest five. In each unit, all trees with circumference (girth) at breast height (GBH) above 16 cm were measured and identified. Each unit was divided into 10 subplots, so as to allow the evaluation in areas of 100 m2 (10x10 m), 200 m2 (10x20 m), 300 m2 (10x30 m), 400 m2 (10x40 and 20x20 m), 500 m2 (10x50 m), 600 m2 (20x30 m), 800 m2 (20x40 m) and 1,000 m2 (20x50 m). Treatments (sizes) were analyzed by analysis of variance, maximum curvature methods and sampling effort. The results indicated that for areas of Cerrado, Semideciduous Forest and Semideciduous Forest in regeneration plot sizes of 200 m2, 200 m2 and 600 m2 respectively should be used to estimate any of the dendrometric variables or plot size of 200 m2 should be used for estimates of diversity only. These results are very useful for a number of environmental researches, improving forest inventory operations by preventing unnecessary sampling effort without jeopardizing accuracy.