Characteristics of canopy and light transmittance in three types of apple orchards in Weibei areas of Shaanxi Province, China

Abstract

The effect of different modified tree shapes (MTS) on light reception was compared among three types of apple orchards: small-sized canopy, middle-sized canopy and large-sized canopy in Weibei areas of Shaanxi Province, China, by using WinsCanopy2004a (2002) for Hemispherical Image Analysis. The results showed that higher average values of photosynthetic photon flux density (PPFD) under canopy per day appeared in all tested orchards, and the number of branches per 667 m2 was lower, indicating that the modified tree shapes were effective to improve the light conditions of canopy but the pruning amount seemed to be slightly more than the appropriate level in Weibei areas. The middle-sized canopy had the maximal light penetration and the small-sized canopy had the least and the leaf area index (LAI) and the ratio of one year-old shoots to scaffold limbs were maximal in large-sized canopy orchards.