Responses of radial growth to fire disturbance in alpine pine (Pinus densata) of different age classes in Nang County, Xizang, China Variation of competition intensity across a chronosequence in surface fire-mediated Mongolian pine forest VARIATIONS OF SPATIAL PATTERN IN FIRE-MEDIATED MONGOLIAN PINE FOREST, HULUN BUIR SAND REGION, INNER MONGOLIA, CHINA Estimation to Dead Surface Combustible Parameters and Evaluation of Potential Surface Fire Behavior of Artificial Coniferous Forests in Chengde County