by Matt Parratt and co, Forestry Commission, GB
Seed collecting trips often seem to be to exotic locations, gathering taxa from far flung corners of the world to add to collections held by botanic gardens back in the UK. However, as a recent trip to southern Italy demonstrates, there is also great value in collecting much closer to home.
The UK National Arboretum Westonbirt is home to some 15,000 specimens encompassing 4,000 taxa. The arboretum is best known for its stunning displays of autumn colour, but it also has an important role to play in plant conservation and research. As part of the ongoing expansion and enrichment of the collection the arboretum has an active programme of seed collecting expeditions, most recently to southern Italy.
Our first stop was Sicily where we hoped to track down two populations of Tilia platyphyllos subspecies pseudorubra. Local knowledge is key to these trips, and without the assistance of Professor Giovanni Spampinato and Dott.ssa Vittoria Coletta we would almost certainly never have found these trees. The first population consisted of just a few trees, perched high on the walls of a deep ravine formed by a seasonal river in the Riserva Naturale Orientale Fiumedinisi a Monte Scuderi.
The accessible trees had already lost much foliage due to the hard drought in the region this year, but we were able to secure a good sized sample of fruits which cut tests in the field showed to have healthy contents. Interestingly, the foliar characteristics didn’t match those of subspecies pseudorubra, but as seed of T. platyphyllos had never been collected from Sicily before this was an important accession.
The second population was more speculative, the location having come from a herbarium sample taken over a decade ago. As we drew closer to the co-ordinates the track deteriorated significantly forcing us to leave our vehicle behind and continue up the steep hill on foot. It became obvious that there were no Tilia trees in the vicinity, and the exposed, hot dry habitat was unlikely to have been home to them in the recent past. Despite disappointment this still constitutes a positive result, disproving the existence of a population is still useful!
From Sicily we hopped across the strait of Messina to mainland Italy and the Stretto Papaleo wildlife refuge in Parco Nazionale dell’Aspromonte. As on Sicily we had to negotiate a steep sided ravine, but this time we had to contend with a shallow but fast flowing river – getting wet feet was essential! After a fruitless recce up a steep side valley we started to see the distinctive winged bracts and fruits of Tilia on the gravelly river banks and suddenly there were the trees! Another small population of a few trees, but this time matching the descriptions for subsp. pseudorubra and therefore a first accession of the subspecies from Italy for Westonbirt.
Buoyed up by our success the next day we headed up into a different part of Aspromonte, and on to a different species – Abies alba. This part of Italy is the location for several glacial refugia for this species and one population in particular at Serra San Bruno has sparked much interest in forestry circles. However, our target population was further south, near Gambarie in Aspromonte National Park. There were lots of cones, but the vast majority were out of reach – and many were less ripe than we had hoped. Again, without local knowledge we could have spent a long time searching for suitable trees, but Dott. Antonio Siclari was able to take us right to the most likely areas – and fortunately for us spotted a Southern Italian Asp (Vipera aspis hugyi) before any of us could get within striking distance! Having neatly avoided the venomous reptile we found sufficient cones to make a collection albeit via some intricate pole pruner work. Westonbirt propagator Penny Jones is hopeful she will be able to harvest sufficient viable seed to grow back in the UK.
As with all seed collected on these trips this will be x-rayed by Forest Research colleagues at Alice Holt which will not only give us insight into the number of filled seeds, but also the presence of insect larvae which is an important biosecurity measure. Together with a collection made by local foresters from Serra San Bruno we hope that some of the plants produced from this seed will be available for research into potential future provenances for forestry in the UK.
After just three days we already had two of our three target species in the bag, but for the home of the National Collection of Maples, the collections of Acer lobelii were especially important. The species is reasonably widespread in cultivation in the UK, but Westonbirt Dendrologist Dan Crowley suspects that the vast majority of these are from just one or two clones. Our first two locations were superbly co-ordinated locally by Dott. Pasquale Santalucia and Dott.ssa Daniela Rinaldi from Regione Campania. Pasquale had mobilised a group of local foresters who had already tracked down one population and collected a good amount of seed for us which gave us a little more time to focus on a high elevation population growing in the vicinity of the Santuario della Madonna di Nova Velia, perched at 1700m AMSL atop Monte Gelbison. Apparently the views here are spectacular, unfortunately we were surrounded by thick drizzle and mist – though that did lend a lot of atmosphere to the location. The trees here were already turning colour, but thankfully there was also plentiful seed, a lot of which was filled with bright green embryos. Another excellent collection!
We had one final location to visit, this time in the Parco Nazionale del Pollino. Our local contact, Dott.ssa Vittoria Marchianò had recently located another Acer lobelii with seed on, but as we only had time to visit one site the following day our only option was to head out the evening we arrived in Pollino National Park and collect the seed by torchlight! The following day we headed across the Park to the Riserva Statale Valle del Fiume Argentino, a steep sided wooded valley which Vittoria had visited earlier in the year to confirm that they were bearing a good crop of fruits. More nimble pole pruner work was required, but we secured our final collection from a mature tree on the riverbank at 206m AMSL, 500m below the minimum altitudes stated in the literature. With these 7 accessions from different populations of A. lobelii, the species is now considerably better represented in cultivation – provided germination is successful! Whilst collecting this species it was increasingly apparent that there is a considerable morphological variation, particularly in characters such as the glaucousness of young stems, and the hairiness of leaf undersides; hopefully the plants raised from these accessions will exhibit this range too.
Without the knowledge and help of local colleagues these important collections wouldn’t have been possible. Our thanks for their help, their expertise, and also for their incredibly warm welcomes go to Prof. Giovanni Spampinato and Dott.ssa Vittoria Coletta of the Mediterranean University of Reggio Calabria, Dott. Antonino Siclari of Parco Nazionale dell’Aspromonte, Dott. Pasquale Santalucia and Dott.ssa Daniela Rinaldi of Regione Campania, Dott. ssa Vittoria Marchianò and Dott. Giuseppe De Vivo of Parco Nazionale del Pollino, and Dr. Fulvio Ducci of the Council for Agricultural Research and Economics (CREA) and Forestry Research Centre (CREA-SEL).