The remarkable story of how Hong Kong’s loneliest tree could save a species, via Scotland
- The tree was remarkable in quality rather than appearance, so could have been easily missed by the average hiker
- And yet it could change the fate of a species in the city, offering hope that it could be revitalised
Decades ago, sitting alone on a slope of Hong Kong’s highest peak, stood a remarkable tree.
The simple conifer, which would have been passed without a second thought, is a gem because it was a female. Today, it has become a key that unlocked an attempt to resurrect a species of tree that had nearly gone extinct in the city.
“Most, if not all of the remaining trees of Amentotaxus argotaenia in Hong Kong show signs of having been cut down in the past. It is a very slow growing species with durable timber and would have been prized for that,” said Craig Williams, the head of horticulture at Kadoorie Farm and Botanic Garden in Hong Kong.
“The drastic cutting would have left the trees open to infection, which is likely the cause of the decline in health in a number of the remaining individuals.”
Around 2018 Williams believed he had found a healthy tree in, of all places, Scotland. It had been grown from seeds found by the Royal Botanic Garden Edinburgh in the 1970s from our lonely tree in Hong Kong.
Martin Gardner, the coordinator of the Edinburgh-based International Conifer Conservation Programme said: “When I visited in 1993 there was only one tree in its native habitat of Tai Mo Shan Country Park, in the New Territories. It was a small, female, multi-stemmed tree of five metres in height but known to be sterile.
“This appears to be the location – and, therefore, the specimen from which seed was located by Royal Botanic Garden Edinburgh in the 1970s. Therefore, it is most likely we are bringing the story full circle,” he said.
Once the tree in Scotland was discovered, the gardens in the UK and Hong Kong began to work together. In Scotland, cuttings were taken from the catkin-yew and carefully nurtured until they were strong enough to transport.
When they arrived in Hong Kong in 2020, they went through a strict procedure to ensure they did not carry foreign pathogens, were planted on a managed site and began their journey towards reforestation.
“There are no seedlings in the vicinity, and we have not observed any elsewhere, so despite this, natural recovery does not appear to be happening at all,” said Williams.
He said he hoped the story could inspire a nugget of hope for the role botanic gardens can play in reforestation projects.
“This is a great example of the genuine conservation potential of botanic gardens’ living collections. We aim to provide interpretation alongside a few specimens in our public display areas to explain the story of their amazing journey from one tree in Edinburgh,” he said.
In Hong Kong, another species of tree, Podocarpus neriifolius, has been nursed back to viability. Similarly to the catkin-yew, the scientists were at first only aware of one tree in the city, which lived in the New Territories.
A colleague of Williams was able to propagate and grow other trees from its cuttings, which were male. The scientists then located a female on Hong Kong Island and planted cuttings close to the males, hoping that they would reproduce.
“The important point is whether the remaining individuals are able to grow, cross-pollinate, set seed and recruit offspring,” said Williams.
“Often we find that these basic processes have been disrupted and are no longer working, and so the species is effectively functionally extinct. There is a worrying number of species that match this description in Hong Kong.”
