Crown dynamics and growth on eucalypt clones stands submitted to artificial pruning in an agroforestry system / Dinâmica de copa e crescimento de clones de eucalipto submetidos a desrama em sistema agroflorestal

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The crown dynamic, growth and time spent to prune were evaluated in two eucalypt clones stands, in an agroforestry system, in a 9.5 x 4.0 m spacing, in Vazante, MG (1736 S, 4642 W and altitude of 550m). Pruning treatments included control and removal of one third or one fourth of the plant live crown height, with or without removal of some thick branches above this point, with different number of pruning intervention. At 15 months of age, after the second artificial pruning intervention in some treatments, clone 19 presented a larger leaf area index (LAI = 0.44) and smaller transmittance of photosintetically active radiation (t% = 68%) than the clone 58 (LAI = 0.26 and t% = 80%). At this age, treatments with removal of one third or one fourth of the live crown of the plants, with six months intervals between pruning interventions, at 9 and 15 months of age, presented a larger t% for both clones as compared to treatments pruned only at 9 months of age, benefiting the agricultural crop to be planted at this age. The LAI and t% values indicated that the studied clones present high crown recovery capacity after pruning. The growth in diameter, total height and volume outside bark of clone 58 did not differ significantly (p>0.05) between the pruning treatments until the age of 30 months. The total time spent to apply artificial pruning to a height of six meters did not differ significantly (p>0.05) between the pruning treatments, indicating that by applying four pruning interventions at shorter intervals there is no increase in the cost of this operation as compared to three interventions. Although there was no significant difference in plant growth between pruning treatments it is recommended to prune one third of the height of the live crown, with the removal of some thicker branches above this point, using four interventions, allowing for knotty core reduction and, consequently, wood quality increase. And, to establish agroforestry systems, clone 58 is considered more adequate than the clone 19 for favoring radiation transmittance for the agricultural crops or pasture of the consortium.

ASSUNTO(S)

desrama eucalipto crown dynamics clones sistema agroflorestal silvicultura agroforestry system clones eucalyptus dinâmica de copa artificial prunning

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