The ancient oak trees in Blenheim Park tell a story of hope

The natural diversity of species in ancient oak trees is greater than previously thought. This is the conclusion of research led by a Dutch botanist in a British forest with the highest density of ancient oaks in Europe.

“Here in this tribe, we have made an exciting discovery.” Aljos Farjon leans cautiously forward to look at the fallen hollow tree. “In the brown rot of old oak we found a very rare false scorpion (Dendrochernes cyrneus), a spider with the appearance of a scorpion. The insect lives in the mildew of the brown wood of the oak tree, just like many other insects.”

Farjon takes a handful of wood chips. “Look, this is the work of the brown tree ant that digs tunnels in the brown rot. The colony of ants lives in the oak tree. You can rarely see them, because they don’t like daylight. The oak ant.”

Nowhere in Europe are there so many huge oak trees clustered together as in the enclosed part of Blenheim Park near British Woodstock, called High Park. Farjon painted here 275 oak trees with a trunk circumference of more than five metres. All of them are mature trees that are between four hundred and eight hundred years old. “This is unprecedented. There is nowhere in Europe where there are so many old oak trees together,” says Varjon. For comparison: there are approximately 170 oak trees with a trunk circumference of more than five meters throughout the Netherlands.

strict conditions

The secret to Blenheim Park’s high density of mature trees is that the site was off-limits to the public for centuries. Scientists are not allowed to wander here except under strict conditions.

The unique oak forest, about 100 kilometers northwest of London, dates back to the Middle Ages. King Henry I of England used this forest for deer hunting since 1100. After the park came into the ancestral possession of Winston Churchill in 1764, the landscape designer decided to leave 150 hectares of woodland alone. This is due to the unique huge oak forest on the edge of Blenheim Park. Among the trees on the rolling hills, Blenheim Palace can be seen in the distance, the famous birthplace of the British Prime Minister with its round neck.

Farjon highlighted the existence of the exceptional oak forest in 2016 when he wrote a public book on the oldest oak trees in England:Old Oaks in the English landscape. Then it made the national news. “I was amazed at the amount of giants I could find here. This is when I came up with the idea to work with scientists to make an inventory of the biodiversity of this unique place.”

The 77-year-old Farjon (born in Hilversum) is a leading pine expert by training. His name is a scientific standard work in which all 615 species of conifers in the world are described. After retiring from the Royal Botanic Gardens Kew in London, he devoted himself to researching ancient oak trees.

The national tree

The oak is the British national tree. Hanging oak trees aren’t called English oaks for nothing. The National Trust for Nature and Culture has the oak leaf as its logo. Farjon: “You can tell from everything that old oak wood holds a special place in British culture, history and people’s hearts.”

The enclosed oak forest in Blenheim Park is Valhalla for lovers of ancient oaks. There is practically no maintenance here. The thick trees that are falling down remain lying there, just like broken branches. Farjon says the alternation of live and dead oak makes it a paradise for species diversity.

“The longer the wood remains, the more valuable it is as a habitat for beetles and fungi. Many insects are specialized and associated with a certain stage of oak decay. It also applies to mushrooms and fungi.” Moments later, Farjon plunged his head into the large hollow of a giant fallen oak tree. “In it, a mycologist discovered an extremely rare bright orange fungus. This was the second discovery in Britain.”

hollow inside

All old live oaks are hollow inside. This says nothing of their vitality, Farjon emphasizes the flabby lad. It is said that this tree may be a thousand years old. The tree is still in foliage and may also be producing acorns. As long as the cambium is in contact with part of the root system, the tree is alive. To properly understand a tree, you must realize that it is a completely different organism than an animal. If an animal loses a leg, it is doomed. The tree is divided. So if a tree loses a branch, it regenerates elsewhere in the tree.”

Elder oak trees are known to rank highly as hosts to hundreds of species of insects, fungi, and plants. Five years of environmental fieldwork at Blenheim Park has revealed staggering numbers. Figures that exceed the previously known biodiversity value of oak trees.

Led by Aljos Farjon, a team of fifty environmental experts studied the huge oak forest. Traps were set up over and around the logs to catch insects. Using magnifying lenses, the experts studied the bark of old oaks for lichens.

ice Age

“The lichen connoisseurs were especially lyrical,” says Farjon, as he walks among the giant oaks. “The lichen researchers were amazed at the number of species they found in ancient live and dead oak trees. They even found two new species in Britain.” The researchers identified 231 species of lichen and 480 species of fungi.

The abundance of insects also amazed the researchers. A total of 930 species of beetles, 684 species of moths and nearly 700 species of flies are found in and around the oak. Among them are many rarities associated with the old oak. This also applies to butterflies such as the great reflective butterfly and oak leaf.

What is the reason that oak trees in particular are so high in biodiversity? Farjon explains that this is a matter of evolution. “The longer a tree is in the ecosystem, the more species will enter into a relationship with this tree. Oaks have been growing in England since the last Ice Age, over ten thousand years ago. We are still learning about this tree’s value for biodiversity.”

cry along

The sum of five years of ecological field research on the ancient oak trees in and around Blenheim Park was overwhelming for Farjon. He’s working on a book with results. “We found approximately 4,100 species of organisms in a 130-hectare site.”

High Park Blenheim is now in the top three sites of highest biodiversity in the UK, along with the New Forest and Windsor Great Park. “But the other two places are places where research into biodiversity has been going on for decades. So I suspect Blenheim Park will score higher in the long run.”

The proven huge diversity of species in the ancient British Oak Forest is hopeful evidence for the Dutch world that nature is more powerful than we think. “There is a lot of talk in our time about how bad things are with nature. Concerns about climate change and species extinction dominate the news.”

“I find it unfortunate that so many conservationists cry with this story. Our research at Blenheim Park proves that biodiversity is very rich if you do proper research. The ancient, untouched oak trees here tell the story that everything in nature does not deteriorate.”

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