Dynamics of heights and stem diameters in short-rotation woody crops (SRWCs) in NE of Romania

Data are collected from short-rotation woody crops (SRWCs) installed in NE Romania (close to the border with Ukraine), located in the hilly area (Suceava county), at an average altitude of 350 m. SRWCs were installed in 2014–2016 with two hybrid poplar clones: AF8 (P. x generosa 103-86 x P. trichocarpa PEE) and Pannonia (P. x euramericana), at a planting spacing of 3 x 2 m (with 1667 trees/ha), from rods (2 m long cuttings) as planting material. The rods were planted in the soil using a planting machine at a depth of 0.6 m. During each growing season, regular maintenance work was carried out. The inventory was carried out after 5, 6, and 7 growing seasons, and the choice of sample areas (3 x 10 trees for each variant) was made to avoid marginal influences. Heights (m) was measured on trees at ground level using a router (ensuring 1 cm accuracy) for each year/season of growth in the trunk node (insertion site of lower-order trunk segments). Diameters (cm) were measured on the trunk at one metre intervals (from the base to the top, where it was a whole multipu -1 m) using forest calipers, ensuring an accuracy of 0.1 cm. The height data can be used to generate the evolution of height growth for each crop variant. Results can be compared between growing seasons for total values. From base to top, diameter can generate the shape of the tree stem, comparing the two clones analysed in relation to planting density.