The abundant shrub species,obvious stratifications and complex shrub layer structures,which are the most outstanding characteristics in the coniferous broad mixed forest in the Russia plain. X 2 and r formulae are used on studying the interspecific association and correlation of shrub layer.Based on analytical results of X 2 and r formulae,plants of shrub layer can be divided to 4 ecological species groups: Cytisus fish+Juniperus communis,Fraxinus excelsior+Ulmus laveui...