3D representation of 7 and 14 year old raspalje. These poplar trees were planted as live pole cuttings, each pole being several meters long and pushed into the ground at a depth of 1 m. Adventitious lateral roots then grow from this pole, which can be considered analogous to a central tap root. Therefore, root systems of plantation-grown poplars are simpler than seed-grown, tap-rooted conifers such as maritime pine (Pinus pinaster Ait). Trees were planted at a density of 200 stems/ha−1 in two neighboring stands located in northwest France (Moulin de Bariteau, Chinon, 0°14′ E, 47°10′ N). The study area was flat with an elevation of 37 m. Mean annual precipitation is 820 mm•yr−1, and the prevailing wind direction is northwest. Mean wind speed ranges from 4.5–5.5 m•s−1 (Météo-France). The soil consisted of a clayey sand (69% sand, 21% clay, and 10% loam) and lacked a hard pan in the top 1.0 m. During the investigation, the ground water table was 1.2 m deep.

http://archiroot.org.uk/archilibrary/Raspalje2y.wrl
http://archiroot.org.uk/archilibrary/Raspalje7y.wrl
http://archiroot.org.uk/archilibrary/Raspalje13y.wrl

Data collected by the GIP ecofor project "peuplier". Info at dupuyl@yahoo.com