[Age structure and growth characteristics of Juglans cathayensis seedling populations at different slope aspects in Wild Walnut Natural Conservation Area of Xinjiang, China]. / æ–°ç–†é‡Žæ ¸æ¡ƒè‡ªç„¶ä¿æŠ¤åŒºä¸åŒå¡å‘é‡Žæ ¸æ¡ƒå¹¼è‹—ç§ç¾¤å¹´é¾„ç»“æž„åŠç”Ÿé•¿ç‰¹å¾.

For grasping the composition and growth characteristics of seedling populations of Juglans cathayensis, a national grade 2 endangered plant, four 2-hm2 plots were set up at different slope aspects in Wild Walnut Natural Conservation Area of Xinjiang, China. Adjacent lattice method was used to survey J. cathayensis seedlings. The relationships between the number, basal diameter and plant height of J. cathayensis seedling populations were analyzed. The results showed that seedlings at 1st age were more abundant on sunny, semi-sunny, shady and semi-shady slopes. The number of seedlings was predominant at 1st-3rd age. Seedling populations at different slope aspects showed an expanding age structure. 5.7% of 1st age seedlings could survive to 4th age, and 1.7% could survive to 7th age. The number of J. cathayensis seedlings had a critical turning point at the 3rd age. The seedlings of J. cathayensis were considered as r-strategists in their lives. The basal diameter and plant height of seedlings were slow-growing before 3rd age and fast-growing after 3rd age. Average growth rate of basal diameter was 3.6 mm·a-1and decreased in the order of shady slope, sunny slope, semi-shady slope and semi-sunny slope. Average growth rate of plant height was 9.0 cm·a-1 and decreased in the order of sunny slope, semi-sunny slope, semi-shady slope and shady slope. Basal diameter and plant height of seedlings exponentially increased with the increase of age. The relationships between plant height and basal diameter showed power function. Growth rates of seedling traits could be reflected by the properties and parameters of functions.