ONE of the joys of being officially retired is that I can now choose what to do with all of my time, not just evenings and weekends. I don’t need to graft to earn a crust any more but, like many of my peers, I am able to offer my services to any deserving cause that takes my fancy.

I’ve turned out for the Yorkshire Wildlife Trust and North York Moors National Park for a while now but this year saw me starting to volunteer for another organisation - Kew Gardens or, to give it its official Sunday name, the Royal Botanical Gardens at Kew.

My commitment doesn’t involve travelling down to London (thank goodness) because the experts at Kew are in the middle of an ambitious undertaking which involves the whole country.

It’s called the UK National Tree Seed Project and its aim is to create a repository of viable seeds from all the important native tree and shrub species in the country at the Millennium Seed Bank.

The impetus for the scheme came in 2012 when the infamous ash dieback disease was first recorded in Britain. This event highlighted just how vulnerable our native species are to such attacks and the Tree Seed Project was started the following year funded by players of People’s Postcode Lottery.

The Royal Botanical Gardens have living examples of our native trees and shrubs, either at Kew or its sister site at Wakehurst in Sussex, so in my naivety I thought they could just collect seeds from there and put them in the freezer – not so apparently.

To preserve the full genetic diversity of the UK’s trees, collections need to be made from all corners of the country, North Yorkshire included, and will involve an enormous number of people, trees and seeds.

The project isn’t even halfway through yet and already 12.5 million seeds have been collected from more than 8,000 trees. My contribution as a minion in the North Yorkshire volunteer team has been much more understated but, I’ve got to say, very satisfying.

In the last few months, under the guidance of our Kew-trained leader Nigel, we have concentrated our efforts on three species within the North York Moors – bird cherry, crab apple and guelder rose.

Kew’s collecting parameters are very exacting; all of our trees needed to be growing in or near ancient woodland to ensure their native provenance, and close enough to each other to be regarded as a related population.

Our first job for each species was to find at least 15 individual trees which fitted the criteria and the time of year to do this varied for each type of tree. Bird cherries for instance, with their tiny black fruits containing just one seed, are quite difficult to spot in August when the fruits are ripe but springtime is a very different matter.

In May the whole tree is festooned with spectacular, candelabra-shaped flower stalks, each bearing scores of white blooms. The foam-covered-canopy effect was visible right across the Murk Esk Valley at Beckhole, where the collection was made, so mapping the trees to return to in late summer was a relatively easy task, armed with a pair of binoculars.

Trying the same strategy for our crab apples wouldn’t have worked as the trees and flowers are almost indistinguishable from the domestic apple which isn’t a native species – it originates from the Tian Shan mountains of Kazakhstan would you believe.

We needed to wait until the small, yellow fruits appeared in September to be sure that we had Malus sylvestris and not Malus domestica.

It was while the team was collecting our 3,000 crab apples from the wonderful Levisham Woods that we noticed some guelder roses growing in nearby hedgerows.

They may be small and relatively inconspicuous bushes but their berries gave them away, being just about the most intense crimson colour to be found anywhere in the plant kingdom.

As we would find out later, the berry juice stains clothes and skin the same bright red and, bizarrely, smells unpleasantly of mouldy cheese.

Our collecting season is over for 2018 and Nigel has posted the team’s hard-gotten seeds off down south to represent North Yorkshire’s gene pool for three of our special native trees. I’m already looking forward to 2019 and wondering what our target species will be next year.

If you would like to know more about the project then have a look at kew.org/blogs/kew-science