Tree planting – dormancy delayed due to warm weather

The autumn colouring of the foliage of trees has been spectacular. The brightness and intensity of colour have been very special this autumn/early winter. I mention early winter intentionally, as the trees have been very slow to drop their leaves. However, looking at the hedges surrounding the fields, another factor has been clearly displayed: differences in the way the trees have reacted to the warmer weather. Take for example, mature oak trees: looking at similar oaks in the same hedge, some have now lost their leaves, while others comparable in size and age are still holding on to their splendid deep yellow coloured foliage.

These effects are due to the very high summer temperatures and droughty conditions. Cracks in the soil made it possible for the hot air –average temperatures in the UK have been about 2°C above normal – to travel deep into the sub soil. The resulting effects are now clearly visible. Trees in general are hanging on to their foliage for approximately 3 weeks longer than normal.

This has had an effect on trees in the nursery. In short, the lifting of fruit trees has to be delayed because the roots of the trees are still growing, which in turn is delaying dormancy. To lift fruit trees BEFORE dormancy will harm them. It will be possible to begin lifting trees only in the week after Christmas.

Oak trees, November 2018, showing different stages of leaf yellowing