Cupressus arizonica is one of the most important species for forest plantation in degraded ecosystems and dry and semi-dry shrub-lands in Iran. It is an important species for urban green space. In this research the effect of various shading treatments were considered on seedlings first growing season height growth. A complete randomized design with four replications was performed. At first 24 quadrates including 24 seedlings in each quadrate (in total 576 seedlings) were indicated. Six different light treatments including 0, 33%, 50%, 67% and 100% and one treatment including the seedlings under Walnut trees canopy (%75 cover) with four replications were performed. Seedlings heights were recorded in 9 times. The results showed that maximum seedlings height growth ratio (%40.6) was occurred until July. Maximum seedlings height growth and minimum seedlings height growth and mortality respectively occurred under walnut canopy and full light treatments. Such increments were not significant in next months of the period of study. Final seedlings height in artificial shade treatments was greater than full light treatment. Generally, the results proposed that using %33 full light treatment (% 67 projected shades) and special tending practices in July and August of the first growing season to enhance Cupressus arizonica one-year-old seedlings in the study area and similar districts.
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