Yield class is an index used in Britain of the potential productivity of even-aged stands of trees. It is based on the maximum mean annual increment of cumulative timber volume achieved by a given tree species growing on a given site and managed according to a standard management prescription.
Yield Class It is measured
- in cubic metres / hectare / year
- in multiples of 2 (even number)
- i.e. 12, 14, 16, etc. Example:
- a crop of yield class 14 is capable of growing an average of 14 m3/ha/year over its lifetime Crops should be at least 12 - 15 years old before assessment
- as all site factors will have come in to play
Yield Class Sitka spruce
- Yield Class varies from 14 – 24
- Greater yields have been achieved
- Sites that are not considered able to achieve Yield Class 14 with Sitka spruce are not grant-aided Lodgepole pine
- Yield Class varies from 8 – 16 Broadleaves
- Yield Class varies from 4 - 12