Plant shape

Trunk length

Increasing trunk length has the following effects:

  • Decreasing ground frost risk
  • Decreasing the beneficial effects of convected heat from the soil. Chaptal (1943) found that the average difference between maximum temperatures at 20 cm and 2 m above the soil was 1.6°C
  • Easing of manual operations. The optimum height for workers is 1.1 – 1.4m
  • Easing of weed control and mechanical harvesting
  • Increased starch storage, leading to more regular yields and increase in sugar levels
  • Decreased risk of downy mildew and grey rot
  • Decreased vigour due to increased resistance to sap flow
  • Increased drought sensitivity

Canopy shape

Features of an ideal canopy (for cool climates):

  • Maximum exposed leaf area
  • Homogeneous canopy density at 15 shoots/metre
  • Homogeneous canopy thickness of 1 leaf or less
  • 60% or more fruit exposed
  • 10 – 20 node shoot length
  • Renewal & fruiting zones well aerated and exposed to the sun
  • Shoots droop after veraison
  • Trellising is cheap to install and maintain
  • Plants establish themselves quickly, and husbandry costs are low
  • Machinery designed for its upkeep is available.