This report covers the current state of a specimen of Phytolacca dioica. It is done after a visit during the week of the 7th July, 2014, as requested by the Course Director at Real Club de Golf Las Brisas at Marbella.
It is decided to inspect several trees of this species to assess the risk of falling after one them was found broken in the same area.
1. Location
The specimen is located at the Real Club de Golf Las Brisas at Marbella. It is placed close to the cart path on the 18th hole and at the limits of the course and adjacent to the boundary.
2. Decription
These Phytolacca dioica trees are not part of the original project by Gerald Huggan. Instead, they were planted around the 1989-90.
This tree has a typical wide base, with an estimate surface of 4 square metres. From this base evolve 5 trunks with an average diameter of 45cms each. Each branch measures around 9 metres. So the tree presents an asymmetric top with wider canopy in the North/South axis, probably due to past pruning.
From a mechanical point of view, this species develops a good number of branches that form a complex web, laying one on top of another, forming a very stable structure in a three dimensional web. In this case, we can find many scars from previous pruning.
We found several areas of rotting at the base, so surgery is recommended to check the inside and to decide future actions. One can smell the typical odour after fermentation, coming from decomposed fibres found in each wound.
Figure 1. Points of infection with rotten base.
3. Assessment
We used a visual evaluation and a tree surgery to analyse the tree.
After the surgery, a wide part of the base were found with a bacterial infection, not linked with any fungi, but to confirm this point a sample should be sent to the lab.
Figure 2. Rotten area at the base before surgery.
Figure 3. Healthy wood after surgery.
We found a discontinuity between fibres, due to included bark in the branch union, which becomes a structural failure where the branch can break apart in a relative short period of time.
Figure 4. Detail of the structural failure.
4. Corrective measures
We have decided to clean all the infected area flushing it with water under pressure, and spraying with pure garlic extract (antiseptic potential) and with Trichoderma (to colonise the area protecting from further invasions).
Figure 5. Area of failure and proposed cut point (in red)
It is important to cut one of the main trunks, marked in red in the picture, since it presents included bark in the union (in green) which is a weak structural point. This is crucial since the tree presents a wide target (high risk to damage).
This problem is the same that caused the other tree to fall down.
Figure 6. Phytolaca fell a few days before due to the same reasons, structural problems.
The big hole done after the surgery needs to be filled with soil to prevent from future water accumulation, which will favour bacterial infection.
In the future, the tree will be reassessed to study the evolution of the damage. If the infection has colonised new tissue, tree felling is recommended.