• Drought is a prolonged period of dryness, causing extensive damage to vegetation and preventing successful growth.
  • The impact of drought on trees varies on an annual basis, based on weather and site conditions.
  • Drought damage is caused by periods of dry soil conditions and can affect all tree and shrub species.

Drought affecting jack pine

Symptoms and damage

  • Drought can have significant impacts on trees in a short period of time.
  • Symptoms can include wilted foliage, sparse canopy, leaf scorch, yellowing, leaf drop and pre-mature fall colouration.
  • Trees may respond to drought with pre-mature leaf drop and in long lasting or severe drought periods, branch and crown dieback may occur.
  • Drought damage is often very patchy throughout a forest stand due to variable site conditions.
  • Growth for several seasons may be stunted even if there is sufficient rainfall after a drought event.
  • Often trees suffering drought are more prone to invasion by insects and disease causing organisms, as the trees are in a weakened state.

Leaf scorch on red oak caused by drought

Control measures

Trees that have been damaged can be helped by ensuring they are well-watered during the growing season. Slow, deep watering of roots under the tree canopy is the preferred method.