Soil moisture controls on the dynamics of nonstructural carbohydrate storage in Picea meyeri during the growing season

•P.meyeri tends to increase soluble sugars and starch under low soil moisture conditions.•Needle soluble sugars were more sensitive to air temperature than other organs.•NSCs in the shoots and stems were affected by both soil moisture and atmospheric factors.•Stem soluble sugars had a different response to soil moisture and vapor pressure deficit.•Root NSC reserves may be important for P.meyeri to respond to low soil moisture.