Goodbye Sycamore
Release date: November 28th 2008

It was with great regret that the decision was recently taken to fell the impressive sycamore that has stood for so many years outside the entrance to the Nicholsons nursery. The Notice of Intent was published on November 14th by Forester, Adam Quant. It read as follows:

"In approximately two weeks time we intend to remove the sycamore tree which stands next to the main entrance gates of Nicholson Nurseries."

"Externally there are no signs of decay in the main stem. However, over the past two years we have been monitoring the main stem with Picus Tomography. As a result of last year’s tomograms we decided to reduce the tree by removing the upper crown which was already receding. This left a tree with good shape and vigor but, as result of the most recent tomogram, we now believe it is not safe enough to be retained."

"The most recent tomogram shows that decay is starting to reach the outside of the tree. There is an increasing probability that this tree could fail catastrophically during a storm. Given the tree is adjacent to both the public road and bus stop for the school we consider it the best option to remove the tree."

Since then, Syril has been successfully felled. Examination of the main stem confirmed that the extent of the internal decay was just as serious as the surveys had predicted. So, what is a Tomogram?

Background to Picus Tomography

Measurements using Picus Tomography are based on the fact that sound wood is a better sound wave conductor than wood damaged by decay. The device uses a series of sonic sensors which detect waves induced and propagated through the wood. A small tap on a metal pin is all that is required to send sound waves through the tree, which are received and measured by all the other sensors

The resultant tomography provides a clear and precise indication as to the extent of any damage within the stem at the test location. The different colors on the image represent different degree of problems from dark brown, representing sound wood, through to light blue or white, which indicates a cavity.

The upper scan shows the state of the tree approximately 1 metre above ground level, while the second shows the extent of the decay at 2 metres. These can be compared with the actual results, revealed after felling, as illustrated by the accompanying photographs.

We regularly use this method for assessing the condition of trees when carrying out Duty of Care assessments for farmers and landowners. If you would like to find out more about this service, please don't hesitate to Contact us.