Tree inspection and assesment

Anyone with keen eye will have most probably already seen plastic or even metal tags nailed to trees in parks, usually at the height of two or three metres. These tags are uniquely numbered and indicate that the tree is part of a tree register. This register keeps track of the condition of the trees, changes in their condition, the interventions that have been carried out and those that are still needed, or even the time of the next inspection. The inventory of trees is preceded by a visual tree inspection, during which we record the tree's data and give it a unique identification. 

Since this tree inventory system works very well in parks, some people have already asked whether it would be possible to do this even for trees in their private gardens. It is not uncommon for a large yard to have up to a dozen large trees, but we have also worked in the gardens of condominiums where there were as many as forty to fifty trees. Therefore the demand and the need for this is quite understandable, so we have expanded our services and are now registering all trees  where there is a request. The client will receive documentation of the tree and will be kept informed of any inspections or interventions that are due. 

The process of visual tree assessment may seem trivial, but it is a complex and important task. Usually, when one thinks of a tree, one imagines a trunk and a canopy. 

When my colleagues and I carry out a visual tree assessment, the first thing we look at is the root zone, which is usually an area of 1,5 metres from the edge of the crown. Here we can see a lot of warning signs: roots running on the surface, cracks in the soil, but even a rut caused by cars can indicate a number of problems. 

Then, starting at the bottom and working our way upwards, we continue with the investigation. The tree flare is one of the most sensitive parts of the tree and it is often damaged by string trimmers. The condition of the tree flare often indicates the condition of the root system as well. 

Looking further at the tree, we study the trunk. It's a resilient and well-regenerating part of the tree and also easy to inspect, so if we find a fault here, we're not alarmed. 

The scaffold branches that form the crown start growing from the base of the crown. This is another very sensitive point in trees. It's usually harder to see, but the angles between the branches are telling a lot of information. 

Most often clients call us because of the visible defects in the crown of the trees since a dry branch is easy to spot. We always look at the length of the twigs at the ends of the branches. Just like a diary, trees also tell us what has happened to them in previous years through its branches. 

Once the tree has been examined as a whole, it is also necessary to observe its wider surroundings, because even the demolition of a building close to the tree can create new wind tunnels that can affect the tree and alter the conditions around it. 

A visual tree inspection cannot reveal two key areas: the tree's internal structure and its root system. Fortunately, modern, non-invasive tools can now provide accurate assessments of both. 

The ArborSonic 3D Acoustic Tomograph measures the speed of sound traveling through the wood to determine the internal condition of the tree and shows with extreme precision the load the tree is bearing at the height of the measurement. This inspection and its evaluation is always carried out by my colleagues who are qualified tree assessment specialists. 

The tree assessment methods are a great help to be able to tell the condition of trees and to take them into an inventory, but they do not replace professional tree care. Both visual and instrumental inspection are only complementary to it.