Dataset: Canopy Nitrogen addition promotes xylem formation of Castanopsis chinensis (Sprengel) Hance in a subtropical forest in China

Increased atmospheric nitrogen (N) deposition caused by intensive anthropogenic activities resulted in inconsistent effects on the xylem formation of trees, in N-limited boreal and temperate forests. However, the effects of N deposition on xylem formation of trees in subtropical forests, are still poorly understood. The aims of the study were to (i) characterize the dynamics of xylem formation in <i>C. chinensis</i> in a subtropical forest in China and (ii) determine the effect on xylem formation of adding N to the canopy. From 2013-2016, 50 kg N ha^-1 yr^-1was applied over the canopy of <i>C. chinensis </i>at the end of each month (April to October) in a subtropical forest in southern China. Then, the dynamics of xylem formation including the width of cambium cells, enlargement cells, wall-thickening cells and mature cells were monitored during 2015 and 2016 using a microcore sampling approach.