Supersizing Broadleaves

Supersizing Broadleaves is an innovative project investigating seed source, nursery stock production and tree establishment in the UK. It asks, ‘What happens when you take the best seed available, raise it with the best practice for the particular species and site, and establish it in the best possible way?’

Future Trees Trust has been working over the last twenty years to identify superb examples (called plus trees) of oak, sycamore, birch and cherry.  We have brought these plus trees together in grafted clonal seed orchards to produce qualified seed for industry.  In 2023, we established progeny trials for these species to understand adaptive traits and assess family performance in a range of environments.  By selecting the best trees, it should be possible to grow higher quality timber in terms of form and vigour.  However, genetics only accounts for a small amount of variation in growing timber.  Variation occurs at every step of the tree production process whether this is selecting the biggest acorns, growing trees in cells rather than bare rooted and thus reducing root damage, or having a more sheltered or fertile site. All influence how well a tree gets established.

This project seeks to investigate some of these variables to help trees get established more quickly and therefore reduce the need for weed control. So far, we have planted three full factorial trials of pedunculate oak, silver birch and sycamore using source identified and qualified material on a range of sites in northern England. We expect that qualified material that is cell grown and planted with good weed control will establish more quickly than source identified material with no weed control, and that where nutrients are limited, an addition of NPK fertiliser will improve growth.

Furthermore, the quality of the plants produced in terms of root architecture can have a significant influence on how quickly trees get established.  We have carried out root architecture assessments on six of each bare rooted and cell grown species, of both qualified and source identified material and calculate root shoot ratios on a further six trees of each seedlot to give baseline data on root structure.  FTT will also carry out some ‘destructive sampling’ (the removal of material from a specimen for research purposes) two years after planting to reevaluate the root architecture and tie this back to performance.  We will therefore destructively sample 288 trees from each trial site (six trees from each of 48 treatments) to see how well the trees have performed.

In addition to establishing research trials, four monographs (in depth literature reviews) for the species being studied, and also wild cherry, Prunus avium, have been written to help forestry practitioners decide on which species to plant, which nursery production method to use, and which management interventions are needed (you can download these at the bottom of the page).

Trial establishment, root architecture assessments and collection of baseline data was carried out in winter 23/24, and we have collected year 1 height data in November 24.