A 4-hectare Pinus tabulaeformis permanent sample plot was established on Eastern Hunshandake sandy land in 2008 in order to study the stand structure of P.tabulaeformis forests fragmentarily distributed on the sandy land in the Eastern Inner Mongolia Plateau,which play a key role in sand fixation and climatic regulation.All the trees with diameter at breast height(DBH) equal to or more than 1cm were located and monitored.There are 7 363 genotype individuals in the stand(sample plot),belonging to 10 tree spe...