What is a Clonal Seed Orchard and Why Does it Matter
A clonal seed orchard, often referred to as a CSO is a carefully designed collection of selected trees established to produce improved seed for future forestry and woodland creation.
At Future Trees Trust, clonal seed orchards are created using grafted copies of outstanding individual trees, known as plus trees. These parent trees are identified through extensive selection work across Britain and Ireland and are chosen for desirable characteristics such as timber form, growth performance, health and adaptability. Grafted copies of selected parent trees are planted together in an orchard where they can flower, cross-pollinate and produce seed for future generations of trees.
The resulting seed combines the genetics of carefully selected parent trees, helping to improve the quality, productivity and resilience of planting stock available to foresters, landowners and woodland managers.
An Oak CSO at Whitfield estate, Herefordshire
Why does Future Trees Trust use clonal seed orchards?
The long-term goal of Future Trees Trust is to increase the availability of improved broadleaved tree seed for the UK.
Many broadleaved species are planted for a range of objectives, including timber production, biodiversity enhancement, carbon sequestration and landscape resilience. The quality of future woodlands is heavily influenced by the quality of the planting material used to establish them.
By bringing together carefully selected parent trees from across Britain and Ireland into a single breeding population, Future Trees Trust can ensure that the outcomes of tree selection and breeding research are translated into improved seed for practical forestry use.
This approach allows the Trust to move beyond simply collecting seed from individual trees in the wider landscape. Instead, it creates managed breeding populations that can deliver improved seed while maintaining genetic diversity through cross-pollination between multiple selected parents.
Clonal seed orchards also provide an important link between tree breeding research and practical forestry. They enable the genetic gains achieved through selection and testing programmes to reach nurseries, woodland creation projects and future forest owners.
Silver Birch CSO at Maelor Forest Nurseries
Why not simply collect seed from outstanding trees?
Collecting seed from an outstanding tree does not guarantee that the resulting seedlings will inherit all of its desirable characteristics. The pollen parent also contributes to the next generation, meaning the quality of seed collected from individual trees can be difficult to predict.
Clonal seed orchards help address this challenge by bringing together many carefully selected parent trees within a managed breeding population. This increases the likelihood that seed will result from crosses between trees chosen for desirable characteristics such as timber form, growth performance and resilience.
From Plus Trees to Improved Seed
The process starts with the identification of exceptional trees in the landscape.
Researchers and partners identify plus trees that display desirable traits. Material is then collected from these trees and propagated by grafting to produce genetically identical copies. These grafted trees are planted within a clonal seed orchard where they can grow, flower and exchange pollen with other selected individuals.
Over time, the orchard produces seed that can be supplied as Qualified Forest Reproductive Material (FRM), providing a valuable resource for the forestry sector. Future Trees Trust complements this work with progeny testing, helping to evaluate how offspring perform under different growing conditions and informing future breeding decisions.
Delivering Improved Seed for Key Broadleaved Species
Future Trees Trust has established clonal seed orchards for several of the UK’s most important broadleaved tree species.
Current Qualified seed orchard programmes include:
- Silver birch (Betula pendula)
- Sycamore (Acer pseudoplatanus)
- Wild cherry (Prunus avium)
- Sessile oak (Quercus petraea)
- Pedunculate oak (Quercus robur)
- Sweet chestnut (Castanea sativa)
These orchards form the foundation of a long-term effort to improve the supply of high-quality seed for British forestry whilst supporting resilient and productive woodlands for future generations.
You can read more on this here:
Wild Cherry, Birch and Sycamore
Some of Future Trees Trust’s orchard programmes are already producing seed.
The Trust’s wild cherry, birch and sycamore orchards bring together selected parent trees from across their natural range, creating genetically diverse seed sources for future planting. Ongoing management work focuses on maintaining orchard performance and maximising the quality and diversity of future seed crops.
This improved seed is also supporting wider research initiatives, including projects investigating how genetics, nursery production and establishment techniques influence long-term tree performance.
Building the Next Generation of Oak Seed Orchards
Future Trees Trust continues to invest in new orchard development, including major oak initiatives at Craven Field.
The Craven Field sessile oak seed orchard will bring together around 60 selected parent trees sourced from across the UK and Ireland. Through grafting, these will become approximately 400 orchard trees, creating a nationally significant future seed resource. As the orchard matures, it is expected to provide a supply of improved acorns for woodland creation, timber production and long-term woodland resilience.
Alongside establishment work, Future Trees Trust continues to manage existing oak orchards, carrying out stocktakes, replacing missing clones and collecting graftwood to maintain orchard performance and genetic representation. This work helps ensure that valuable genetic resources are retained within the breeding population and remain available for future seed production.
2 year old Oak at nursery for planting out at Craven Field
Looking to the Future
Clonal seed orchards are a long-term investment. Some species may take many years before producing significant seed crops but once established they can provide improved reproductive material for decades.
For Future Trees Trust, these orchards are the practical delivery mechanism for the tree breeding programme. They bring together decades of tree selection, grafting, breeding and genetic evaluation to produce improved seed for future woodlands.
By combining tree selection, breeding, orchard management and progeny testing, Future Trees Trust is helping to ensure that the next generation of broadleaved trees will be better equipped to meet the challenges facing British forestry, from climate change and emerging pests and diseases to the need for sustainable domestic timber production.
References and Further Reading
Future Trees Trust. Guidance on Seed Use
View Guidance
Future Trees Trust. Orchard Data Sheets and Qualified Seed Orchard Information
Available through the Guidance on Seed Use resource above.
Jo Clark. Utilising Forest Genetic Resources: The Work of Future Trees Trust
View Presentation
Future Trees Trust. Craven Field Sessile Oak Seed Orchard Project Information
View Information Sheet
Future Trees Trust. Developing seed orchards for wild cherry
Future Trees Trust. Oak Clonal Seed Orchard Management Update
https://www.linkedin.com/company/future-trees-trust/