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Seed Source

Why is seed source important

Many British native trees have been growing in the UK for over 8,000 years. During that time they have become well adapted to their local growing conditions, i.e. the climate, altitude and soil fertility. Seed collected from these trees will therefore produce the most suitable progeny for planting back into that locality when compared to using plants from continental Europe for example. For many years, plant specifiers have not asked enough questions regarding the source of the nursery stock they are planting. Much of the stock used to plant native woodlands has come from unsuitable sources outside the UK.

Local provenance - What does it mean? Why is it important?

The Forestry Commission has divided the UK into four Regions of Provenance; 10, 20, 30 and 40. These are then subdivided into ‘local seed zone provenances’ as shown on the Forestry Commission seed zone map. The local provenance boundaries are mainly based on natural boundaries formed by geological and climatic features of the UK. Maelor Forest Nurseries Ltd has been a key player in promoting the use of British seed sources, and endeavours to supply planting stock from as wide a range of UK provenances as possible each year. We recommend the use of the Forestry Commission’s map of Seed Collection Areas (see below) and the associated table of native species to be encouraged in each zone. These are published in Forestry Commission Practice Note no. 8 and are helpful when choosing the right species for the right location. At Maelor, our seed collections are batched according to these areas. Plant specifiers should use the map as a tool for describing to nurserymen the provenance from which they wish to buy stock. The seed zone identity numbers shown on the map are listed in our catalogue against each batch of native plants.

There are a number of reasons for using local provenance stock for native woodland creation purposes:

Improved survival rates and productivity

Trees grown from British seed sources are able to withstand British weather conditions. Generations of trees living and reproducing in one location results in the trees adapting to expect, and thrive on, the local prevailing amount of rain, warmth, light etc. Trees subjected to a differing climate than their genetic origin has programmed them for will probably be less productive than local provenance trees, if indeed they even survive.

Protection of Environment and Wildlife

If a tree from Italy, France or even the south of England is planted in Scotland it is likely to flush (open buds) much earlier than the existing local trees, as its genetics require a much shorter cold period to convince it that winter is over and spring has begun than the local trees do. Differences like this will have knock on effects, for example the wrong amounts or types of food or shelter may be available at critical times of year. Leaves, flowers or fruits may not develop in time for when local insects or animals require them, or may develop too early and be damaged e.g. by late frosts.

Conservation of genetic material

Importing of European tree sources has resulted in hybridisation of tree genetics which could result in significant changes to the aesthetics and ecology of our landscape, for example there are very few native black poplar left in the UK – virtually all poplar seeds contain either hybrid or entirely introduced genetics.

However...

As the UK’s climate alters the trees that have adapted well to the previous weather patterns may begin to struggle! Woodland management approaches are altering; creating productive woodlands for the future will probably be best achieved by planting a carefully considered variety of species and provenances.

Effects of climate change on tree planting

Global climate change is widely accepted – wetter, warmer winters are predicted in the UK coupled with hotter drier summers, in the near future. Although this pattern hasn’t been clearly seen in recent summers or winters, it is apparent that the UK weather is changing.

Concerns over the productivity of British woodlands in the future British climate have led to much debate and consultation regarding the sourcing of planting stock, and research is currently underway regarding this topic. The overriding conclusion seems to be that we cannot predict the future weather, and the only prediction we can make is that we expect more frequent and more extreme weather events.

The recurring ideas regarding insurance against a changing climate seem to include:

  • Plant species mixtures – not all species will be affected to the same extent and some will be much more tolerant to varying conditions than others. The range of tolerance of any given species is important to be aware of, as extreme weather events (e.g. sharp winter frosts / storms or summer heatwaves/ droughts / floods) may end the survival of some species that previously survived in Britain.
  • Provenance mixtures will provide some insurance, however tree species should be well matched to site conditions, e.g. trees from southern provenances may suffer frost damage in spring if planted on a more northerly site. The actual characteristics of the planting site must be considered, i.e. altitude, climate and even aspect when selecting planting stock. A damp north-westerly facing slope may suit an entirely different provenance or species than a warm dry south-easterly facing slope in a nearby location.

Provenance is everything when selecting planting stock, whether it is for native woodland creation or commercial timber production. Plant buyers should be fully aware of the characteristics of their site and their requirements, and request the most suitably sourced stock from nurseries to achieve maximum productivity in the long run. Forestry Commission bulletin 124 An Ecological Site Classification for Forestry in Great Britain (2001), by G. Pyatt, D. Ray and J. Fletcher is applicable to all types of woodland. It matches key site factors including soil classification with the ecological requirements of different tree species / woodland communities, and is a useful forest planning tool for a wide range of management objectives.

Where are our trees sourced from?

We produce the majority of our broadleaf stock from our own seed collections in all corners of the UK; we are therefore always on the look out for new seed collectors and new sites to collect seed from. If you are interested in collecting seed, or are a landowner or manager with a native woodland or large hedgerow that may be suitable for seed collections, then please contact Nikolay Cvetkov by emailing seed@maelor.co.uk or telephoning 01948 710606. Rates of pay for seed collections / landownership royalties on asking.

Our coniferous stock for productive commercial forestry is propagated or raised from the very best genetic material. Seed is obtained from seed orchards or specific stands with desirable characteristics. We are keeping up to date with current thinking and keeping aware of plans for forestry in the future, and selecting our seed sources accordingly to produce stock that will achieve the maximum possible productivity throughout its lifetime, even in the face of a changing climate. Our seed sourcing extends beyond the UK and we have links with companies across Europe and North America, this network allows our seed to be sourced from the best the world has to offer for a given species.

Seed Testing Station

Maelor Forest Nurseries has been appointed as an official facilty to carry out statutory seed testing in Great Britain. This allows us to carry out official tests on seed for sale.