Brazil has large stretches of degraded land, mainly occupied by pasture. Recently, the Brazilian government created a program providing financial support to recover these lands throughout the country by establishing agroforestry systems, among others. To select the most appropriate initial spatial arrangements and tree planting density for such systems, the plant growth and leaf area index (LAI) of a Eucalyptus camaldulensis clone were evaluated in five spatial arrangements: 3.6 9 2.5 m, and 3.3 9 3.3 m (monoculture), and (2 9 2) ? 10 m, (3 9 3) ? 9 m, and 9 9 3 m (silvopastoral systems), with 1,111, 918, 833, 556 and 370 plants per hectare, respectively. The arrangement did not affect plant height growth (p [ 0.05) up to 50 months. The average diameter was affected by plant proximity in the planting line, being smaller (p \ 0.05) in the arrangements (2 9 2) ? 10 m, and 3.6 9 2.5 m, and by the number of lines in the rows, as the plants in the single line arrangement (9 9 3 m) attained the highest diameter. Individual volumes of high initial density stand were lower than in the silvopastoral systems. The arrangements (2 9 2) ? 10 m, 3.6 9 2.5 m, and 3.3 9 3.3 m did not differ (p [ 0.05) in volume per hectare, which was higher (p \ 0.05) than for the other arrangements studied. LAI decreased with age and it was higher (p \ 0.01) in the monoculture as compared to the silvopastoral systems. The silvopastoral system can be established in the (2 9 2) ? 10 m arrangement for high biomass production besides having the additional benefit of financial returns from the pasture, as compared with the monoculture. The 9 9 3 m arrangement is preferable for large diameter log production.

RESUMOOs estudos direcionados para quantificação de estoques de carbono fixado por florestas naturais estão em ampla evidência, assim como a discussão sobre a efetividade da recuperação de áreas degradadas como estratégia para reduzir os níveis de CO 2 atmosférico. Neste sentido, tiveram-se dois objetivos neste artigo: i) quantificar o estoque de carbono presente na biomassa da parte aérea de um fragmento de Floresta Estacional Semidecidual Montana, pertencente ao Bioma Mata Atlântica no estado de Minas Gerais e ii) incorporar a variável estoque de carbono na estrutura horizontal da análise fitossociológica e comparar os resultados aos obtidos pela metodologia padrão, sem utilizar essa variável no cálculo do valor de importâncias das espécies. Os resultados indicam que o estoque de carbono encontrado equivale a fragmentos em estágio médio de sucessão, e que a utilização da variável carbono influencia sobremaneira o valor de importância das espécies. Esta metodologia serve como suporte para a escolha de espécies arbóreas de maior potencial para sequestrar carbono e pode subsidiar programas de restauração de remanescentes florestais do Bioma de Mata Atlântica. Palavras-chave: Mata Atlântica; estoque de carbono; sequestro de carbono; estrutura horizontal. ABSTRACTThe studies directed to quantify the carbon fixed stocks by natural forests are in ample evidence, as well as discussion about the effectiveness of the recovery of degraded areas as a strategy to reduce atmospheric CO 2 levels. In this sense, this study had two purposes: i) quantify the carbon stocks present in the shoot biomass of a tropical semi-deciduous Montana fragment, which belongs to the Atlantic Forest biome in Minas Gerais state and; ii) incorporate the variable carbon stock in the horizontal phytosociological analysis structure and compare the results to those obtained by the standard methodology without using the variable in the calculation of the species importance value. The results indicate that the carbon stock equals to the fragments found at the intermediate succession stage, and that the carbon variable use greatly influences the species importance value. This methodology serves as a support for the selection of species which present the greatest potential to sequester carbon and may support programs for the remnant restoration of the Atlantic Forest biome.

Resumo -O objetivo deste trabalho foi avaliar o uso de decepa de plantas jovens de eucalipto, para produção de árvores de menor diâmetro, com colheita facilitada por pequenos produtores; ou para recuperação de povoamentos jovens severamente danificados e produção de biomassa para energia em ciclos curtos. O experimento foi conduzido em sistema agroflorestal, com espaçamento entre plantas de 9,5x4 m. O crescimento de plantas intactas foi comparado ao de brotações de decepas realizadas aos nove ou doze meses após plantio. Aos seis ou nove meses após a decepa, realizou-se a desbrota, para deixar dois ou três brotos por cepa. Quando a desbrota foi realizada aos 12 meses após a decepa, todos os brotos dominantes foram deixados. Um tratamento sem desbrota também foi avaliado. Aos 42 meses após plantio, o tratamento sem desbrota apresentou o mesmo número de brotos por cepa que o de plantas desbrotadas para três brotos. O diâmetro das brotações foi equivalente a 69% do valor estimado para as plantas intactas. O valor assintótico de produção das brotações, da maioria dos tratamentos de decepa aos nove meses, foi igual ao das plantas intactas, o que evidencia a viabilidade da decepa sem a realização da desbrota, em sistemas agroflorestais.Termos para indexação: Eucalyptus, clone de eucalipto, desbrota, madeira para carvão, recuperação de povoamentos. Juvenile eucalypt plant coppicing and sprout management in agroforestry systemAbstract -This study aimed to evaluate juvenile eucalypt clone plant coppicing, in order to obtain small diameter logs, in the first rotation, which facilitates harvesting by small farmers; or to recover damaged young stands and to produce biomass for energy in short rotations. The experiment was carried out in an agroforestry system with 9.5x4 m spacing. Intact plant growth was compared to sprout growth from coppicing at nine and twelve months after planting. At six or nine months after coppicing, sprout thinning was carried out to leave two or three sprouts per stump. When thinning was done after 12 months of coppicing, all dominant sprouts were left. A treatment without thinning was also evaluated. Forty-two months after planting, treatment without thinning showed about the same amount of sprouts per stump as those thinned to three sprouts per stump. The estimated asymptotic value for sprout diameter was 69% of that for intact plants. The asymptotic value for sprout production, for most treatments of plants coppiced nine months after planting, was similar to that obtained for intact plants, which indicates that coppicing young eucalypt plants, without sprout thinning, can be used in agroforestry systems.

This study aimed to identify pruning intensity and frequency that can be applied to eucalypt without imposing growth reduction, in an agroforestry system in Brazil (17°36' S and 46°42'

The growth of intact plants and coppice of juvenile plants of eight eucalypt clones (3 9 3 m spacing) was evaluated in the savanna region, Brazil (17°36 0 09 00 S and 46°42 0 02 00 W), aiming for biomass production for energy in short rotations. The treatments included intact plants and juvenile plant coppice (cut at 13 months of age). Coppice was managed either with thinning to two sprouts/stump at 9 months after harvesting or without sprout thinning. The diameter of the intact plants was greater than that of coppice for clones 58, GG100, 26 and 8B, and no differences were noted between treatments for the other clones. Yield did not differ between the thinned and unthinned sprouts for most clones. At younger ages, the coppice yield was greater than that of the intact plants for most clones. Later, there was a decline in the coppice yield, and intact plants surpassed coppice. Then, the maximum coppice mean annual increment was achieved at younger ages than for the intact plants, which resulted in coppice rotation age shortening. The greatest differences between the coppice and intact plants yield was between 38 and 40 months, when the coppice yield was 59, 56, 127, 149 and 75 % greater than that of the intact plants, for the clones 58, GG100, 1000, 36 and 910, respectively. Clone GG100 revealed the highest yield estimation among the intact and coppice plants. The results indicate that by coppicing juvenile eucalypt clone plants, in dense stands, it is possible to produce biomass for energy, without sprout thinning, if rotation age is shortened.

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Eucalypt has been widely planted in Brazil, in the savannah region, which is characterized by high soil water deficit and low fertility. Dieback, leaf area index (LAI) and yield of young stands of 16 eucalypt clones were studied in Vazante, MG, Brazil (17º36’09"S and 46º 42’02"W). It was determined for each clone: a) the proportion of the tree height with dieback symptoms in the apical terminal (HWD%) and the proportion of trees with dieback (NWD%), at 13 months (end of the first dry season); b) the LAI at 13 and 21 months, and c) the yield at the age of 13, 19 and 25 months. HWD% reached 5-9%, and NWD%, 50-80%, for the five most susceptible clones, when the soil water deficit reached 508 mm in the year. LAI varied from 0.61 to 1.56, at 13 months, and from 2.31 to 3.48 at 21 months, presenting inverse relationship with dieback. The least susceptible clones to dieback achieved the highest yield up to 25 months of age. There was interaction between dieback and fertilizer levels only for three clones. There was a positive correlation (p < 0.001) between the LAI at the age of 13 months and the periodic monthly increment from 0 to 11 months, and from 11 to 19 months. The difference in dieback susceptibility among clones allows the selection of genotypes for regions where the soil water deficit is a major limiting factor.