By Mark Kinver
Science and nature reporter, BBC News
A potentially devastating tree disease is not to blame for the demise of about 200 English oaks in Leicestershire, say UK Forestry Commission scientists.
English oaks have a high degree of resistance to sudden oak death
Pathologists ruled out "sudden oak death", despite the infected trees having bleeding bark lesions, one of the disease's key symptoms.
The absence of a rhododendron species, which carries the disease, in the area meant it was not to blame, they said.
They added that further analysis was ongoing to identify the exact cause.
To date, sudden oak death fungus (Phytophthora ramorum) has not been recorded to affect the English oak (Quercus robur), which has a high resistance to the fungal infection.
A senior scientist for the Forestry Commission's research centre told BBC News that it was "unfortunate" that sudden oak death had been suggested as the cause of the infection in Booth Wood, near Loughborough.
"Unless you have infected Rhododendron ponticum in very close proximity to these trees, it can't possibly be sudden oak death," she explained.
"And there are no rhododendrons in this woodland, let alone infected ones."
Sudden oak death, which can attack the leaves and trunks of susceptible species, was first recorded in April 2002 at a garden centre.
In autumn 2004, a significant outbreak was discovered in Cornwall and a smaller one was found in South Wales, affecting a number of the evergreen holm oak (Quercus ilex).
The Forestry Commission says that unless the "levels are intense", the disease is unlikely to infect European species of oak, such as the English and sessile oak.
Broadleaf species that are at most risk include beech, sycamore and horse chestnut.
The exact cause of the infection in Booth Wood is still being investigated, and Forestry Commission researchers say they will report their findings in the coming months.