Variation in tracheid characteristics along a latitudinal gradient
Most of the traits, except for earlywood tracheid diameters (CTD, CRD), showed a latitudinal pattern (Fig. 5). However, no significant trends were found between traits and longitude (LON) and altitude (ALT) (p>0.05). Generally, traits of latewood decreased faster than those of earlywood as latitude increased, suggesting a climatic shift along latitude is more related to the change of latewood than earlywood traits.