Effects of Cutting Density on Growth, Yield and Quality of Poplar Clone Seedlings

In order to identify the optimum cutting density for producing the highest number of plantable seedlings of poplar clones, a split-plot randomized block design was used to establish four cutting densities in plots. Based on data on the survival, leaf area, seedling height, caliper, and biomass of 1-year-old seedlings of clones Nanlin-95, Nanlin-895, Nanlin-1388 and NL-80351, the growth characteristics and seedling quality under four cutting densities were analyzed. Results indicated that the leaf area, stem and leaf biomass, and caliper of seedlings of all four poplar clones increased with the decrease in cutting density. Leaf area index reached its highest level at the spacing of 40 cm×40 cm, while the aboveground biomass of the seedling on an area basis increased as the cutting density increased. Seedling quality at low cutting density was higher than that at closer cutting density. The quantity of first-grade seedlings (grade I) for clones Nanlin-95 and Nanlin-895 was achieved at the spacing of 40 cm×50 cm; for NL-1388 and NL-80351, it was 50 cm×50 cm. According to the seedling quality and the number of plantable seedlings produced, the suggested cutting density for these four poplar clones was 50,000 stems/hm2.