Influence of wind loading on root system development and architecture in oak (Quercus robur L.) seedlings.

Abstract

The effect of wind loading on seedlings of English oak (Quercus robur L.) was investigated. Instead of using a traditional wind tunnel, an innovative ventilation system was designed. This device was set up in the field and composed of a rotating arm supporting an electrical fan, which emitted an air current similar to that of wind loading. Oaks were sown from seed in a circle around the device. A block of control plants was situated nearby, and was not subjected to artificial wind loading. After 7 months, 16 plants from each treatment were excavated, and root architecture and morphological characteristics measured using a 3D digitiser. The resulting geometrical and topological data were then analysed using AMAPmod software. Results showed that total lateral root number and length in wind stressed plants were over two times greater than that in control trees. However, total lateral root volume did not differ significantly between treatments. In comparing lateral root characters between the two populations, it was found that mean root length, diameter and volume were similar between the two treatments. In trees subjected to wind loading, an accentuated asymmetry of root distribution and mean root length was found between the windward and leeward sides of the root system, with windward roots being significantly more numerous and longer than leeward roots. However, no differences were found when the two sectors perpendicular to the wind direction were compared. Mean tap root length was significantly higher in control samples compared to wind stressed plants, whilst mean diameter was greater in the latter. Wind loading appears to result in increased growth of lateral roots at the expense of the tap root. Development of the lateral root system may therefore ensure better anchorage of young trees subjected to wind loading under certain conditions.

RELATIONSHIP BETWEEN LIGNIN CONTENT AND QUALITY OF Pinus taeda SEEDLINGS1

“…Corroborating with the above, Tamasi et al (2005) reported that more robust and lignified roots from the upper third of the root system of Quercus robur L. seedlings conferred greater resistance to the swinging movement of the shoot and promoted greater anchoring of seedlings with the ground in response to the effects from wind strength. Voelker et al (2011) reported that a reduction in the survival of Populus spp seedlings hybrid was proportional to the lignin content found in the cell walls of the conducting vessels, thus reducing field survival up to 60%.…”

The effect of mechanical stimulation on root and shoot development of young containerised Quercus robur and Robinia pseudoacacia trees

“…Although not always unambiguous, several types of mechanical, morphological and biomass distribution responses have been observed so far (e.g. Berthier and Stokes 2005a, b;Danjon et al 2005;Goodman and Ennos 1998;Goodman and Ennos 1999;Nicoll and Ray 1996;Stokes et al 1995Stokes et al , 1997Tamasi et al 2005;Telewski 1995).…”

Towards developmental modelling of tree root systems

“…Danjon et al, 1999aDanjon et al, , 2005. The first method is generally more precise, but fairly time consuming, the second method cannot precisely record the geometry of non-rigid roots (Tamasi et al, 2005), and a certain amount of roots are lost during uprooting, though the amount of roots lost can be estimated with no extra measurements/data . The range of the most commonly used digitiser has a radius of 5 m, though longer roots can be measured either according to Danjon et al (1999b) or according to Edwards (2003).…”

“…Today, the most widely used method is 3D digitising with a Polhemus 3D low magnetic field digitiser, coding in the .mtg format and data checking and analysis with the AMAPmod software (e.g. Danjon et al, 1999aDanjon et al, , 2005Tamasi et al, 2005;. .…”