Impact of spacing on quantitative and qualitative characteristics of walnut (Juglans regia L.) plantation

This research was conducted by randomized completely block design with nine spacing treatments (2×2, 2×3, 3×3, 3×4, 4×4, 4×5, 5×5, 5×6 and 6×6 m) and three replications at Chamestan research station. The research area is located in the north of Iran with mean annual precipitation of 840 mm and brown forest soil with intermediate to heavy texture. Results of ten years walnut spacing trial revealed that mean dbh, mean total height, dbh increment and total height increment of walnut in spacings of 2×2, 2×3 and 3×3 m were minimum. Trees survival was different among nine treatments. Least survival was observed in spacing of 2×2 and 2×3 m. The analysis of qualitative characteristics showed that spacings of 5×5, 5×6 and 6×6 m (with high dimensions) had the lowest quality than other spacings. With above mentioned results we are able to conclude that spacing less than 3×4 m is not suitable for wood production by ten years results