Genuine native crab apples (Malus sylvestris) are notoriously difficult to identify with certainty. In a 1979 survey, only 1% of 3,000 hedgerow crab apple trees in County Durham ticked all the boxes as being the authentic native species. Most candidates are descended from discarded cores of domesticated orchard apples, complex hybrids whose ancestors came from the Tian Shan mountains of Kazakhstan.
I’ve long suspected that one venerable example, in a fragment of ancient oak wood that lies within the boundary of the Prince Bishops’ deer park, might be the genuine article. Bark, leaves, flowers and fruit match descriptions in field guides but I’ve harboured lingering doubts that perhaps it, too, might be descended from a culinary apple core, cast aside during a picnic in the park, long ago.
This summer Dr Heather Knight, one of my former colleagues at Durham University’s biosciences department, tried a hi-tech approach to verifying its credentials. She took a sample back to the laboratory for DNA barcoding, a technology that matches DNA sequences unique to each species against a national reference database.
The results are promising but tantalisingly ambiguous, with a DNA sequence that almost matches several closely related apple species. So, thanks to generations of cross pollination by bees, the ancestry of this tree is perhaps too tangled to ever be absolutely sure of its true identity.
No matter: it is a beautiful old specimen, which lights up its secluded valley in spring with an exuberant display of blossom that belies its age. It plays host to countless insects that collect its nectar and pollen, or feed on its leaves and fruit. But its days are numbered; large branches are dying, its trunk is hollow. An autumn gale might easily deliver a fatal blow. Grazing sheep prevent natural regeneration by its seedlings.
So yesterday, on a warm, hazy autumn afternoon, I returned to collect some seed before it finally succumbs to old age. A faint aroma of cider hung in the air, rising from the carpet of small greenish-yellow apples fermenting under the boughs.
I bit into one to extract a pip: indescribably sour. In flavour, at least, it’s untouched by any hint of domestication.
