Abstract:

The niche breadth and niche overlap of 15 main arbor populations in Thuja sutchuenensis forests were analyzed by a quantitative method. The result showed that the importance value and horizontal spatial niche breadth of T. sutchuenensis was the biggest, the horizontal spatial niche breadth of Carpinus fargesiana, Quercus semicarpifolia and Carpinus cordata var. chinensis was bigger than other species, the horizontal spatial niche breadth of Daphniphyllum oldhamii, Tsuga chinensis, Acer sinense and Macrocarpium chinense was smaller than other species. There was a positive correlation between the horizontal spatial niche breadth and the importance value. Thuja sutchuenensis had bigger horizontal spatial niche overlap with other species, this result reflected that T. sutchuenensis had strong capacity in adaptation and competition. The horizontal spatial niche overlap between the dominant species in T. sutchuenensis forests was smaller, this result showed that T. sutchuenensis forests was stability. The height niche of T. sutchuenensis was smaller than that of Quercus semicarpifolia, Q. phillyraeoides and Acer davidii, because the number of mother trees and saplings was smaller. The height niche overlap betweenThuja sutchuenensis with Cyclobalanopsis gracilis, C. fargesii, Quercus phillyraeoides and Tsuga chinensis was bigger, the reason for this phenomenon was that these species had stronger interspecific competition in light factors.

Key words: Thuja sutchuenensis, importance value, niche breadth, niche overlap