Coppice of juvenile eucalypt clone plants and sprout thinning in an agroforestry system / Decepa de plantas jovens de clone de eucalipto e condução da brotação em um sistema agroflorestal

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Clonal plants of juvenile coppiced eucalypt established in wide spacing (9.5 x 4.0 m) in an agroforestry system were managed to produce small diameter plants but still maintaining the productivity of the agricultural crops and pasture. Intact plants growth was compared to sprouts from plants coppiced at the age of 9 and 12, with sprout thinning for two or three sprouts at the age of 6 and 9 months, and with no sprout thinning. The same clone was planted in 9.5 x 1.5 m, 9.5 x 2.0 m, 9.5 x 3.0 m and 9.5 x 4.0 m spacings at the same time that 9-month-old plants were coppiced. Leaf area and, leaf, branch and stem biomass were evaluated every three months after coppicing. The diameter at breast height and total height were measured at coppicing time and at 9, 12 and 15 months after coppice. Leaf area index was estimated when intact plants completed 24 months and sprouts were 12 or 15 months old. Total leaf area and stem biomass per stump, from plants coppiced at the age of 9 months, without sprout thinning, aged 15 months, were, respectively, 24% and 19% greater than for the 24 month old intact plants. The sprouts of plants coppiced at the age of 12 months presented initial growth rate greater than for that coppiced at the age of 9 months due to a larger stump diameter. The volume of the intact plants aged 24 months was greater than that of the sprouts/stump aged 12 or 15 months. The proportion of the volume per stump of plants coppiced at the age of 9 months, without sprout thinning, in relation to the intact plants, was 34%, 65% and 81%, respectively, at the age of 18, 21 and 24 months after planting. This substantial reduction of the volume difference between the two groups of plants indicates that sprout volume will soon be reaching the intact plant volume. About 95% of the stumps sprouted independently of the coppice age. There were about three dominant sprouts per stump in the treatment without sprout thinning, 12 to 15 months after coppice, indicating that thinning is not required. The management of juvenile plants by coppicing presented low leaf area index, i.e., increased radiation availability for the agricultural crop in the agroforestry system when compared to plantations with reduced distance between plants in the planting row. These results indicate that the juvenile eucalypt clone coppice management - to produce small diameter logs - increases the radiation in the alleys, allowing the maintenance of agroforestry systems.

ASSUNTO(S)

talhadia eucalipto eucalypt brotação sprout thinning agroforestry system sistema agroflorestal silvicultura

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