Improved Sitka spruce produces bigger quality yields

Genetically improved Sitka spruce can produce significantly greater yields of quality timber per hectare, new research from the Forestry Commission has found.

Results from the study show an improvement of up to 130% in volumes of high quality green logs and sawn timber, due to more trees surviving to maturity and more logs available from each tree.

Genetically improved Sitka spruce trees are grown from seeds that have been selected because of the desirable characteristics of their lineage, such as fast growth rates, timber density, straightness, stiffness and low incidence of knots.

It was also discovered that despite faster growth rates, meaning less density in the wood, there was “no significant difference in strength grading pass rates a the sawmill” compared with unimproved stock, making the material available for construction use as C16 and C24 strength-graded structural timber.

However, the Forestry Commission added the study was based on a single site and “caution is required before extrapolating the results to the whole of Britain”.

Earlier research had already found improved Sitka spruce stocks should achieve a 29% increase in quantity compared with unimproved Sitka spruce.