The environmental consultancy says the issue is because of the prolonged period of lack of rain, especially in the east and south-east of England where Christmas trees are planted on light sandy soils.
ADAS says in contrast, trees planted last autumn have stood the early summer very well, but as these reach the end of their growing period, even these are beginning to show drought stress.
June saw several cases of tortrix moth caterpillars causing damage to the needles, stems and buds of some true firs grown as Christmas trees. In some cases, this damage has now been identified as being caused by caterpillars of the light brown apple moth. This is an established pest of Christmas tree species in the UK, where it has been recorded as causing damage, sometimes severe, to Fraser and Douglas firs as well as to spruce trees and some pines.
In the UK the moth a pest of many fruit crops (including apples), shrubs, trees and herbaceous plants. The damage to Christmas trees in the UK has so far been mainly restricted to Nordman and Fraser fir.
Pheromone trap lures are available. Caterpillars of the second generation cause the most damage. Control can be achieved by the application of an insecticide containing indoxacarb.