Transcript
JULIA COOKE
An oak woodland is an ecosystem. That is a biological community of organisms that interact with each other and their physical environment. Quercus robur woodland occurs in the United Kingdom on predominantly clay soils where there is a temperate climate.
Oak woodlands host a unique diversity of plants and animals. And because of their size, the oaks themselves play an important role. Oak leaves, trunks, acorns and roots provide food and shelter for many other organisms, including animals and fungi. There are many species that coexist with the pedunculate oak. For example, purple hairstreak butterflies and various species of fungi.
Some organisms have a mutualistic relationship with the oak, meaning both species benefit. Jays eat many acorns, but they help disperse the seeds too.
Other species are parasitic, such as the knopper gall wasps that form acorn galls, gaining nutrients from the oak, but reducing the number of acorns produced. Oaks can support hundreds of species of invertebrates.
Oak woodlands consist of a suite of plant species that can include bluebells, hyacinthoides non-scripta, and bracken, Pteridium aquilinum. The plant species are often the easiest way to designate an ecosystem. But animals and fungi are key components too.
The plants, animals and other life forms such as fungi, interact in an ecosystem. Here is an example of a food web in an oak woodland. The arrows indicate the flow of energy between different components. Looking at one pathway, the winter moth caterpillars eat oak leaves and so an arrow points from the leaf to the caterpillar, because energy is transferred from the oak to the caterpillar. This energy is then transferred to the blue tit and the sparrowhawk, as one eats the other.
Common types of ecosystem damage are land clearing and heavy grazing, which can destroy an ecosystem, reduce its size, or compromise its resilience by reducing the number of species in the food web.
In the past, forests would have covered much more of the United Kingdom. But today, only pockets remain. Most of these have experienced some form of forestry or other disturbance, such as grazing.
One area of ancient oak woodland is High Park at Blenheim Palace. It's 0.5 kilometres squared. Blenheim Palace was the ancestral home of the Duke of Marlborough. The Palace Gardens, adjacent to the woods, were designed by Capability Brown.
In High Park, there are many very old trees. King Henry protected the forest by establishing it as a rural hunting park sometime during his life from 1068 to 1135. Presumably, some of the forest was cleared when Blenheim was built by the first Duke of Marlborough in 1705. And the oak woodland was also changed through deer grazing.
Here you can see an estate map in 1789, which shows High Wood. Today, the ancient woodland is not pristine or unaltered by humans. But as a deer park, it was afforded an unusual level of protection. Therefore, in part because of the ancient trees, it's a very valuable site.
Woodlands, particularly those with ancient oaks, are highly valued for their biodiversity today. The forest at Blenheim is a site of special scientific interest. The large number of species of animal and fungi that depend on oaks in these ecosystems is extraordinary. There are now few ancient patches remaining. We need to conserve not just individual species, but ecosystems as whole entities.