Influence of environmental conditions and climate changes on radial tree growth is one of the hot issues worldwide. Numerous environmental factors such as temperature, day length, rainfall, drought, snowmelt, nitrogen deposition influence radial growth of trees. Impact of environmental factors on radial growth, cambial activity or xylogenesis of trees monitored by micro-core method is reviewed. The emphasis of the paper is on the modulation by environmental factors of cambial activity and xylogenesis, relevant problems and prospects are also outlined, to facilitate future research in this area.