A PhD study into native acorns and oak seedlings has been undertaken in partnership with Future Trees Trust.

Based at the School of Agriculture, Policy and Development, University of Reading, the 3.5-year doctorate study aims to understand the factors which influence oak masting to inform a strategy to supply native acorns and oak seedlings for conservation and reforestation purposes. It is important for both industry and the wider environmental considerations of climate change adaptation and natural regeneration of oak forests.

The key questions to be addressed by this PhD are:

WHAT ARE THE MAIN DRIVERS OF OAK MASTING IN THE UK?

How does acorn production vary between individual trees and populations from local to landscape level? Is it possible for oak seed orchards to produce a good crop of acorns every year?

OAK FLOWERS EVERY YEAR IN THE UK, BUT WHY DO ACORNS NOT DEVELOP?

  • Flowering phenology: what environmental factors influence pollen and pollination and subsequent acorn development?

IS POLLEN SUPPLY LIMITING? ARE THERE DIFFERENCES IN THE TWO SPECIES?

  • Seed quality: which acorns produce the best seedlings? What are the environmental conditions that produce the best acorns in terms of size, germination, vigour?
  • Annual masting: what can we do to promote annual oak masting in the UK? Are there interventions such as tree density and soil water supply that we could undertake for oaks to mast every year?

The PhD, undertaken by Ryan McClory, will make use of existing wide networks of connections and collaboration with the UK forest industry. The PhD falls within the remit of Action Oak supported by the UK government.

Ryan has recently completed his Master’s degree at Stockholm University, where his thesis was ‘Impact of phenology and shade on growth and survival of oak seedlings and their interactions with pathogens and herbivores’. In addition to his Master’s thesis, Ryan has co-authored one published paper and is the sole author of another.

The oak, for most people an iconic feature of the British countryside, is in fact two species: sessile oak (Quercus robur) and pedunculate oak (Quercus petraea).

Both are native to Britain and hence well adapted to a range of environmental conditions typical for the country. However, the oaks are now facing many pressures, such as air and soil pollution, increasing pests and disease pressure and changing climatic patterns. Records show that the health and survival of established oaks is declining and that natural regeneration of these trees is limited.

Oak is the most important broadleaf species in British forestry and the cornerstone of many valued and much-loved forests, woodlands and copses. Currently it is the most planted broadleaf, and yet the supply of acorns adapted to British conditions to tree nurseries is invariably limited. The demand for oak seedlings is sometimes met by imports of acorns from continental Europe, with the full knowledge that these may represent ecotypes not well adapted to British growing conditions.

Similar to many other tree species, oak produces acorns in a masting cycle, where low production over several years is followed by a large crop. Oak flowers each year, and yet only masts every 5–7 years.

The acorns cannot be stored for long periods of time, increasing the importance of understanding and harnessing the masting cycle for successful native oak regeneration.

The study is funded with support from the Patsy Wood Trust, Action Oak, the Scottish Forestry Trust, the Mabel Cooper Charity, the ALA Green Charitable Trust and the D. G. Albright Charitable Trust.

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