Delivering Britain’s first Tested Oak Seed orchard
Sharing valuable genetic resources for oak tree planting across the UK.
Oak is a fundamental component of British broadleaved forestry, but sourcing sufficient high-quality acorns is a persistent UK-wide challenge.
Oak is a masting species (meaning it produces varying acorn crops each year, with occasional bumper crops typically occurring every four to seven years). Acorns are recalcitrant, meaning they cannot be stored, therefore having a reliable source of acorns is important.
At present there are no productive seed orchards for oak and acorns must be collected from seed stands (groups of trees that have been set aside specifically as a seed source). Although there are many oak seed stands on the national register, many are not well maintained, making acorn collection difficult.
Collection from orchards is easier and more cost-effective, while retaining high levels of genetic diversity. Seed orchards are therefore an attractive alternative where ground vegetation can be easily controlled, trees are widely spaced to promote flowering and can be fertilised to help promote fruiting.
What we are doing
With funding from the Forestry Commission, under their Seed Sourcing Grant programme, the Future Trees Trust is working with Earth Trust and The Sotterley Estate, in Suffolk to develop two dedicated oak orchards for pedunculate oak (Quercus robur) and sessile oak (Quercus petraea) trees– the first of their kind in the UK.
Leading the project, Future Trees Trust will identify and manage trial sites at both Earth Trust and The Sotterley Estate.
The project will begin with the thinning of the trial sites in order to remove brash and other oak species to produce single-species orchards. Future Trees Trust will develop rogueing strategies (a process of selecting genetically favourable trees, and marking out those that do not fit for thinning/removing). Using the data collected across the entire progeny trial series, a desk study will design individual rogueing strategies for each site that sets out which trees will be removed over several rounds of thinning to produce Tested seed orchards.
The orchards will continue to be monitored as increased thinning will be necessary to maintaining large open crowns for flower and acorn development.
The impact we hope to see
The creation of single species trial sites will enable the orchards to be placed on the FRM register. We will further thin these progeny trials, removing a small percentage of the poorest performing families. We will also look at individual tree performance by family, again removing the poorer performers in terms of vigour and form. We will then calculate genetic gains which will increase with increased thinning, without compromising levels of genetic diversity.
This project aims to significantly contribute to the maintenance and restoration of resilient, healthy species of oak stocks across the UK, while also contributing to learning about techniques for managing and planting new woodland.
The quantities of tested acorns available to industry will increase as the trees grow and mature.
The Forestry Commission’s Seed Sourcing Grant programme was established to enhance the quality, quantity and diversity of tree seed sources in England, also underpinning the Government’s renewed commitment to net zero targets.
Forestry Commission blog
Read more about how the Forestry Commission are addressing the need for seed and tackling the demand for quality trees