title: Population structure and spatial pattern of main tree species in secondary Betula platyphylla forest in Ziwuling Mountains, China.
abstract: This study investigated a typical secondary Betula platyphylla forest in the Ziwuling Mountains, Loess Plateau, China. In the sample plot, the DBH (diameter at breast height) class structure of B. platyphylla was bimodal. Individuals with small and large DBH values were abundant. The DBH structures of Quercus wutaishanica and Pinus tabulaeformis were close to that of the logistic model, thus suggesting the increasing population of these species. B. platyphylla and Populus davidiana showed random spatial distributions at almost all scales. However, Q. wutaishanica and P. tabulaeformis were significantly clumped at small scales. B. platyphylla had a negative spatial relation with Q. wutaishanica at small spatial scales. P. tabulaeformis and Q. wutaishanica showed negative spatial correlations at small scales, but they had positive correlations at large scales. These results suggest that P. tabulaeformis and Q. wutaishanica shared habitat preferences at these scales. In the future, the secondary B. platyphylla forest in the Ziwuling Mountains in the Loess Plateau will probably change into a multi-species mixed forest (Quercus-Pinus mixed forest). Assisted restoration strategies must be employed to improve the regeneration dynamics of the forest in the long term.
authors.affiliation: 1] College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, China [2] The Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Yangling 712100 Shaanxi, China.
authors.forename: Di
authors.initials: D
authors.lastname: Kang
authors.affiliation: Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Yaoxin
authors.initials: Y
authors.lastname: Guo
authors.affiliation: 1] The Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Yangling 712100 Shaanxi, China [2] College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi, China.
authors.forename: Chengjie
authors.initials: C
authors.lastname: Ren
authors.affiliation: 1] The Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Yangling 712100 Shaanxi, China [2] College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi, China.
authors.forename: Fazhu
authors.initials: F
authors.lastname: Zhao
authors.affiliation: 1] The Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Yangling 712100 Shaanxi, China [2] College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi, China.
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Feng
authors.affiliation: 1] The Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Yangling 712100 Shaanxi, China [2] College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi, China.
authors.forename: Xinhui
authors.initials: X
authors.lastname: Han
authors.affiliation: 1] The Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Yangling 712100 Shaanxi, China [2] College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi, China.
authors.forename: Gaihe
authors.initials: G
authors.lastname: Yang
mesh_terms: D002681:China; D065928:Forests; D063148:Plant Dispersal; D014197:Trees