This mature Beech (Fagus sylvatica) tree from a garden in Headley, Surrey showed signs of a 'compression fork' which needed to be addressed. A compression fork is a genetic defect common to Beech trees that occurs when the trunk splits into two stems that subsequently grow very closely to each other. Over time incremental growth on each of the stems acts to push the stems apart as if a car jack was positioned between them. The problem can only get worse with time and frequently is the site of 'included bark' where the bark of the two stems is trapped but not joined. Add to this the 'windloading' effect of having a full canopy on each of the stems, and the danger of one of the stems breaking out is very real.
Rather than remove the tree completely, or fell one half which could leave the tree unstable and create large entry points for decay fungi; Surrey Tree Surgeons reduced the canopy to lessen the tree's 'sail area' in the wind. The smaller the leaf area, the less resistance the tree presents to the wind, and thus the smaller the force exerted upon the weak union.
A 'cable brace' was also installed between the two stems. This is a section of high tensile polypropylene rope bound to the two stems which helps to share the wind load. Modern cable braces are designed to flex with the growth of the tree, and can be monitored by Surrey tree surgeons from the ground for signs that they require adjustment. Installing the cable brace Installing the 'cable brace'.
The solution we achieved was satisfactory to the client as it allowed for the tree to be retained, whilst mitigating the risk that the stems may rip out. This solution will however need periodic maintenance to reduce the sail area of the crown and adjust the tension on the cable brace.
It is worth remembering however, that the need for procedures such as this, is greatly reduced through early tree inspections and 'formative' pruning.