Clon-spacing interaction in Populus deltoides.

The objective of this work was to evaluate in Populus deltoides Marshall cultivars USA-Catfish 2 and USA-Stoneville 72 the clon-spacing interaction at different ages. The study was carried out in a systematic spacing experiment, which was located in Alberti, Buenos Aires, Argentina (35° 402 S; 60Q 15' W; 52 m asl). The spacing rankevaluated was from 2.25 m² to 12.25 m² pertree. There were 15 treatments in all. The evaluation of the clon-spacing interaction was made by studying the trends of the individual basal areas, and the maximum and mean heights at 3; 5; 7 and 10 years. Variance Analysis and Comparisons of Means by Tukey were carried out for both clones on the 10th year. There were not any differences between the clones for the studied spacings and ages. Significant structure differences were observed for both ciones between the smallest and biggest spacings on the 10th year. The influence exerted by the competition on the structure was observed in the smallest spacings since the 7th year.

Key words: Populus deltoides - clon spacing -interaction - structure.