A caatinga apresenta uma diversidade de fisionomias e um enorme quadro de degradação, sendo importantes os estudos relacionados a fitossociologia para a caracterização da vegetação. O objetivo deste trabalho foi realizar um estudo de florística e fitossociologia em um fragmento florestal de caatinga no município de Serra do Mel no Rio Grande do Norte. Para realização do estudo foi realizado um levantamento da vegetação adotando-se a Amostragem Inteiramente Aleatória, onde foram marcadas 10 unidades amostrais de 20 x 20 m (400 m²). Foram amostrados todos os indivíduos florestais arbustivos-arbóreos vivos com CAP ≥ 6 cm. Foram avaliados todos os parâmetros fitossociológicos da estrutura horizontal e vertical, a diversidade florística das espécies através do Índice de Shannon-Weaver (H’), dominância de Simpson (C) e equabilidade de Pielou (J’). No levantamento foram encontradas 7 famílias, 12 gêneros e 12 espécies. As famílias com maior número de espécies e de indivíduos foram a Fabaceae e Euphorbiaceae. Croton blanchetianus, Mimosa tenuiflora, Bauhinia forficata, Mimosa ophthalmocentra e Poincianella pyramidalis foram as espécies que assumiram maior importância na área de estudo sob os aspectos fitossociológicos. A área do presente estudo apresenta baixa diversidade de espécies se comparada com outros fragmentos florestais de caatinga já estudados. Palavras-chave: Estrutura; Diversidade; Caatinga. FLORISTIC-PHYTOSOCIOLOGICAL CHARACTERIZATION OF THE WOODY COMPONENT IN A CAATINGA FRAGMENT IN SERRA DO MEL, RIO GRANDE DO NORTE, BRAZIL ABSTRACT:The caatinga presents a diversity of physiognomies and a huge degradation picture, being important the studies related to phytosociology for the characterization of the vegetation. The aim of this work was to carry out a floristic and phytosociological study in a forest fragment of caatinga in Serra do Mel, Rio Grande do Norte. To carry out the study, a survey of the vegetation was performed adopting the Random Sampling, where 10 sample units of 20 x 20 m (400 m²) were marked. All living shrubby-arboreal forest individuals with CAP ≥ 6 cm were sampled. All phytosociological parameters of horizontal and vertical structure, floristic diversity of species was evaluated through Shannon-Weaver Index (H'), Simpson dominance (C) and Pielou equability (J'). The analytic survey found 7 families, 12 genera and 12 species. The families with the largest number of species and individuals were Fabaceae and Euphorbiaceae. Croton blanchetianus, Mimosa tenuiflora, Bauhinia forficata, Mimosa ophthalmocentra and Poincianella pyramidalis were the most important species in the study area under phytosociological aspects. The area of the present study presents low species diversity compared to other forest fragments of caatinga already studied.Keywords: Phytosociology; diversity; Caatinga.

Aims: Percentage of native thorny and thornless Mimosa tenuiflora (Willd.) Poiret trees, and their growth, height and/or diameter class distribution and clustering pattern were determined in a pure stand of this species. Study Design: A survey of the adult and juvenile plants was carried out in a 50 m x 50 m site after 10 years of tree cover regeneration. Place and Duration of Study: The study site was located at Fazenda Nupearido, Patos-PB, Brazil and data collection occurred in September 2017. Methodology: Adult plants with trunk circumference at breast height (1.3 m from the soil) > 6 cm (CBH > 6 cm) were measured for height and CBH, and located within the study area. Juvenile plants (i.e.: CBH ≤ 6 cm) were divided into 4 height classes. The position of only the thornless individuals within the study area was determined. Results: Among the 170 adult plants documented in the area, 95.3% and 4.7% were thorny and thornless, respectively. Height and diameter at breast height averaged higher for thornless than for thorny adult plants (4.13 m and 9.28 cm vs. 3.61 m and 5.90 cm). In contrast, thornless juvenile plants averaged lower for height and basal diameter than the thorny ones. The number of juvenile M. tenuiflora totaled 897 plants, including 58 thornless ones, but percentage of thornless juveniles peaked at 17.6% for 10-to-50 cm high plants. In general, thorny plants showed a clustering pattern of distribution while the thornless plans were randomly distributed. Conclusion: The density, random distribution and growth of the thornless plants suggest the possibility to form thickets of thornless plants in caatinga sites where this tree predominates. Also, these data show that in forested sites with thorny trees that generate thornless mutants, as observed in the Caatinga Biome for M. tenuiflora and other tree species, it is possible to increase the frequency and abundance of the naturally regenerating thornless plants, making easier the exploitation of forest resources, an approach that may be applied in other types of vegetation.

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Aims: Perform a qualiquantitative analysis of adult arboreal individuals in urban roads in the municipality of Várzea, Paraíba, Brazil. Study Design: Census inventory. Place and Duration of Study: Várzea Municipality, Paraíba, Brazil from March to April 2018. Methodology: The qualitative and quantitative census inventory of adult shrubs-tree individuals was carried out in the urban roads of the municipality, the level of inclusion of the individuals was circumference at breast height (CBH) of (1.30 m) was ≥ 6 cm. Common name of the species was recorded, CBH measurements, height of the first bifurcation and total and physical conditions that were classified as good, regular, bad and dead. The data were tabulated, processed and presented in tables and graphs. Results: A total of 429 individuals were recorded on public roads distributed in 20 species. Azadirachta indica A. Juss and Ficus benjamina L. had the highest number of individuals. 85% of the species were exotic and 15% were native. 12 species offered direct nutritional benefit to man and local fauna as they were fruit trees. The physical conditions of the individuals were 55.94% good, 40.33% regular, 3.73% poor, however, 47.50% of individuals had some type of conflict. 41.72% of individuals were concentrated in the diametric class of 15-21 cm. 54.78% of individuals had height of the first bifurcation greater than 200 cm and 62% of the individuals medium size. Conclusion: The afforestation of the municipality was satisfactory in relation to plant health. Attention needs to be paid to the diversity of native species and the injuries caused to vegetation. The height of the first fork was adequate. The trees were medium sized. It is suggested that studies of perception of afforestation be carried out in the municipality.

Capítulo 2: Infiltração de água no solo em três diferentes sistemas de manejo .. 12