Phytosociology and floristic diversity in a cerrado area under different antropization levels, rio pardo de Minas, MG

Este estudo teve como objetivo avaliar a diversidade e a similaridade flor\uedstica de ambientes de Cerrado, sob diferentes n\uedveis de antropiza\ue7\ue3o por uso agr\uedcola e extrativismo, e gerar base de dados para subsidiar propostas de desenvolvimento sustent\ue1vel para a regi\ue3o Norte de Minas e sistemas de agricultura tradicional. Foram amostradas 4 \ue1reas nos seguintes ambientes: Arei\ue3o, Arei\ue3ozinho, Chapada de Latossolo e Tabuleiro, cujas identifica\ue7\uf5es foram feitas a partir de informantes-chave na Comunidade \uc1gua Boa, em Rio Pardo de Minas (MG). As unidades amostrais foram distribu\ueddas em 8 parcelas de 20 x 50 m, com 5 subparcelas. Foram medidos indiv\uedduos arb\uf3reos com circunfer\ueancia ao n\uedvel do solo maior ou igual a 15 cm. Para an\ue1lise dos \uedndices fitossociol\uf3gicos foram calculados os par\ue2metros densidade, domin\ue2ncia, freq\ufc\ueancia, \ue1rea basal e valor de import\ue2ncia, para cada ambiente. Para a diversidade flor\uedstica foi calculado o \uedndice de Shannon (H\u2019) e para an\ue1lise da similaridade o \uedndice de Jaccard (Sij). Em todos os ambientes, foi encontrado um total de 477 indiv\uedduos, distribu\ueddos em 21 fam\uedlias, com 48 esp\ue9cies bot\ue2nicas identificadas e 27 indiv\uedduos n\ue3o identificados. As cinco fam\uedlias mais importantes (maior VI) foram Fabaceae/Papilionoideae, Apocynaceae, Vochysiaceae, Sapotaceae e Fabaceae/Caesalpinoideae. J\ue1 as dez esp\ue9cies de maior import\ue2ncia foram Pouteria ramiflora, Dalbergia miscolobium, Hancornia speciosa, Macherium opacum, Sclerolobium paniculatum var. subvelutinum, Qualea grandiflora, Aspidosperma tomentosum, Byrsonima pachyphylla, Vochysia thyrsoidea e Hymenaea stigonocarpa. O \uedndice H\u2019 foi de 3,01; 2,72; 2,48 e 2,09 para Arei\ue3o, Arei\ue3ozinho, Chapada do Latossolo e Tabuleiro, respectivamente. O \uedndice Sij indicou, para todas as combina\ue7\uf5es entre os ambientes, que existia pouca similaridade flor\uedstica entre eles.The objective of the study was to evaluate diversity and floristic similarity of Cerrado environments, under different levels of anthropization for agricultural usage and extractivism, and to generate a database to subsidize sustainable development proposals for the North region of Minas Gerais State, and traditional agriculture systems. Four areas with different levels of anthropization were sampled, in the following environments: "Arei\ue3o, Arei\ue3ozinho, Chapada de Latossolo and Tabuleiro", whose identifications had been made from key informers in the \uc1gua Boa Community, in Rio Pardo de Minas (MG, Brazil). The sampled units were distributed in 8 parcels of 20 x 50 m, with 5 subplots. The trees with circumference at ground level of 15 cm or bigger were measured. For analysis of the phytosociology indexes the following parameters were calculated for each environment: density, dominance, frequency, basal area, and importance value. For the floristic diversity the Shannon (H') was calculated, and for the analysis of similarity the index of Jaccard index (Sij). In all the environments, it was found a total of 477 individuals, distributed in 21 families, with 48 botanical species identified, and 27 individuals not identified. The five most important (importance value) families was Fabaceae/Papilionoideae, Apocynaceae, Vochysiaceae, Sapotaceae and Fabaceae/Caesalpinoideae. And the ten most important species was Pouteria ramiflora, Dalbergia miscolobium, Hancornia speciosa, Macherium opacum, Sclerolobium paniculatum var. subvelutinum, Qualea grandiflora, Aspidosperma tomentosum, Byrsonima pachyphylla, Vochysia thyrsoidea and Hymenaea stigonocarpa. The H' index was of 3.01; 2.72; 2.48 and 2.09 for "Arei\ue3o, Arei\ue3ozinho, Chapada de Latossolo and Tabuleiro", respectively. The Sij index indicated a small floristic similarity for all the combinations between the environments

EDAPHOENVIRONMENTAL ATTRIBUTES AND DENDROMETRIC PARAMETERS IN EUCALYPTUS SITES IN A TOPOSSEQUENCE AT UFRRJ CAMPUS, SEROP\uc9DICA (RJ)

Este estudo relaciona atributos edafoambientais e par\ue2metros dendrom\ue9tricos de plantios de Eucalyptus urophylla . O experimento foi realizado em talh\uf5es comerciais da mesma idade, no campus da UFRRJ em Serop\ue9dica (RJ), em tr\ueas s\uedtios selecionados em posi\ue7\uf5es topogr\ue1ficas distintas, no ter\ue7o superior (TS), no ter\ue7o m\ue9dio (TM) e no ter\ue7o inferior (TI) da encosta. Foram avaliados: atributos morfol\uf3gicos, f\uedsicos e qu\uedmicos dos perfis de solo; coletadas amostras nos talh\uf5es para avalia\ue7\ue3o do teor de nutrientes; e medidos par\ue2metros dendrom\ue9tricos. Os s\uedtios apresentam diferentes classes de solo, Argissolo Vermelho-Amarelo, Argissolo Amarelo e Planossolo H\ue1plico, dispostos do topo para o ter\ue7o inferior da encosta respectivamente. Foram observadas diferen\ue7as significativas entre os s\uedtios, quanto aos teores de nutrientes e outros atributos qu\uedmicos, que se refletiram nos par\ue2metros dendrom\ue9tricos. Os maiores valores de \ue1rea basal foram observados em TS e TI, respectivamente, 4,11 e 4,64 m2 ha-1. Os s\uedtios onde os atributos edafoambientais mais influenciaram positivamente os par\ue2metros dendrom\ue9tricos do Eucalyptus urophylla foram o TS e o TI.This study relates soil and environmental attributes and dendrometric parameters of Eucalyptus urophylla plots. The experiment was set in eucalyptus sites for commercial production, of the same age, located in the UFRRJ campus, Serop\ue9dica municipality (RJ). Three sites were selected in different topographic positions of the landscape, summit (TS), back slope (TM), and foot slope (TI). Morphological, physical, and chemical soil attributes were evaluated; soil samples were taken from the plots for analyzing nutrient levels; and dendrometric parameters were measured. The sites showed different soil classes, Red-Yellow Ultisol, Yellow Ultisol, and Fragiudult (Planosols), placed from the summit to the foot slope positions, respectively. There were significant differences between the sites for the nutrient content and other chemical attributes, which reflected in the dendrometric parameters. The highest values of tree base area were observed in the TS and TI positions, of 4.11 and 4.64 m2/ha, respectively. The sites where soil and environmental attributes favored most the dendrometric parameters of Eucaliptus urophylla were TS and TI

Litter contribution and decomposition and root biomass production in forests at different successional stages in Pinheiral, RJ

Este estudo objetivou avaliar a deposi\ue7\ue3o e decomposi\ue7\ue3o da serapilheira e a produ\ue7\ue3o de biomassa radicular de tr\ueas fragmentos florestais em diferentes est\ue1gios sucessionais (avan\ue7ado, m\ue9dio e inicial) localizados no munic\uedpio de Pinheiral, RJ. Para intercepta\ue7\ue3o da serapilheira instalaram-se em cada fragmento, dez coletores c\uf4nicos. Avaliou-se a biomassa radicular em dois per\uedodos (chuvoso e seco), amostrando-se pelo m\ue9todo do mon\uf3lito, em 0-10, 10-20 e 20-30 cm e dez repeti\ue7\uf5es por profundidade. N\ue3o ocorreram diferen\ue7as na deposi\ue7\ue3o de serapilheira entre as \ue1reas, mas apenas uma tend\ueancia de aumento com a evolu\ue7\ue3o sucessional. N\ue3o foram verificadas varia\ue7\uf5es temporais de serapilheira entre as \ue1reas mais jovens, inicial e m\ue9dio no decorrer do ano, com tend\ueancia de aumento nos meses de julho e agosto. Em est\ue1gio avan\ue7ado, o aporte da serapilheira p\uf4de ser agrupado em dois per\uedodos: \u201cfevereiro a julho\u201d, menores valores e \u201cagosto a janeiro\u201d, maiores valores. A deposi\ue7\ue3o das fra\ue7\uf5es folhas e material reprodutivo diminu\uedram, enquanto ramos e outros aumentaram com o avan\ue7ar sucessional. A decomposi\ue7\ue3o da serapilheira mostrou em est\ue1gio sucessional m\ue9dio a menor constante k (0,0038 g.g-1.dia-1) e maior tempo de meia vida (182 dias), seguida por inicial (0,044 g.g-1.dia-1 e 154 dias) e avan\ue7ado (0,0064 g.g-1.dia-1 e 108 dias). A biomassa radicular nas diferentes \ue1reas e profundidades, no per\uedodo seco e chuvoso, apresentou maiores valores em est\ue1gio avan\ue7ado, intermedi\ue1rios em m\ue9dio e menores em inicial. As diferen\ue7as sazonais da biomassa radicular ocorreram sobretudo em est\ue1gio m\ue9dio, com maiores valores na coleta de junho.The aim of this study was to evaluate litter input and decomposition and root biomass of three forest fragments at different successional stages (advanced, medium and initial) in Pinheiral Municipality, in the state of RJ, Brazil. To evaluate litter input, 10 conic collectors were installed in each fragment. The root biomass was quantified by monolith method in two periods (wet and dry) at depths of 0-10, 10-20 and 20-30 cm, and 10 samples were collected in each area. To evaluate the decomposition rate in each area, 12 litter bags were distributed. No significant differences were observed for litter input between the areas, but there was a tendency to increase litter input with successional evolution. No significant differences were observed for seasonal litter input between areas during the year, but there was a small increase in the months of July and August. At the advanced stage, litter input could be grouped into two periods: February to July, with lower values; and August to January, with higher values. The leaf fractions and reproductive material input were reduced, while branch and other fractions increased with succession. For litter decomposition, the intermediate stage showed the lowest decomposition constant (k) (0.0038 g g -1day-1) and the highest half life time (182 days) , followed by the initial (0044 g g -1day-1 and 154 days) and advanced (0.0064 g g -1day-1 and 108 days) stages. The root biomass in different areas and depths for both two periods studied showed higher values in the advanced stage, followed by the intermediate stage and the lowest values were found in the initial stage. The seasonal root biomass difference occurred mainly in the intermediate stage, with higher values in June