Effects of Different Spacing on Growth and Yield of Eucalypts Planted on Paddy Bunds

Abstract

The effect of different spacing distances between trees on the growth and yield of eucalypts planted on paddy bunds was studied at two sites, Ban Nhong Nok-eiang and Ban Koh Khanoon, in Phanom Sarakham district, Chachoengsao province. Five different spacings: 0.5, 1.0, 1.5, 2.0 and 2.5 m were used in a randomized complete block design (RCBD) with three replications. Trees were planted in a single row with five different spacing distances. After planting, the growth of sample trees was measured every two months. After three years, the results showed that growth in diameter at breast height and crown width varied with spacing and stand age. Height growth was not correlated to tree spacing. The bole length of trees was significantly different with spacing. The biomass of each fraction per tree was correlated to tree spacing, but the total biomass/ha increased from narrower to wider spacing. The same result was recorded with the fresh weight of trees. Considering the final diameter of trees, the competition effect among trees, the common practices of farmers and the total expenses in tree planting and tending, a spacing distance of 1.5 m was recommended for planting.

Keywords: eucalypts, spacing, paddy bund, growth, biomass