Tree Surveying and Tree Inspections

• The frequency and detail of a tree survey can vary from a less detailed “walk-through survey” to a highly detailed “individual tree survey”. Surveys are individually tailored to meet the specific requirements of each client. 

Level 1 (limited visual) Walkover/Basic

• Assessment involves a visual assessment of an individual tree or a population of trees near specified targets. Targets are buildings, cars, roads, people or events that could be affected by a tree or part of a tree failing. 
• This limited assessment is conducted from a specified perspective in order to identify certain obvious defects or specified conditions. A limited visual assessment typically focuses on identifying trees with imminent and/or probable likelihood of failure. 
• Level 1 assessments do not always meet all of the criteria for a risk assessment if they do not include analysis and evaluation of individual trees. 
• This level can be a drive-by or just a quick walkthrough. 

Level 2 (Full visual tree assessment VTA)

• A detailed visual assessment requires an Arboriculturist to walk completely 360 degrees around the tree.
• Tree dimensions are recorded using hand tools such as diameter tape, laser range finder, and measuring tape; then further information is gathered using basic decay detection tools such as sounding mallet, probes and fungal testing kits to determine initial safety and determine whether further investigation is required, using more detailed methods.
• The assessment provides information on the conditions of roots, buds and leaves together, providing an assessment of general tree health and vitality.
• Each and every tree on a site will be assessed, and all works will be recorded within a comprehensive inventory, e.g. trees' common name, Latin name, tree height, crown spread, DBH. Age, condition, and recommendations.
• Visual assessments of trees rely upon using Visual tree assessment (VTA), this is a non-invasive method of examining the health and structural conditions of individual trees, as written by Mattheck & Breloer Arboricultural Journal 1994.

Level 3 (Detailed Inspection)

• An advanced assessment is performed to provide detailed information on specific tree parts parts, defects orconditionsdition highlighted by the level 2 assessment
• Methods of assessment can include decay detection equipment resistograph, tomography and climbing inspections, root excavations, lean monitoring, pull tests.
• Assessment of defects are confirmed and measured through criteria of failure for hollow or decayed trees, damaged roots, and for tree that are healthy but high trees (H.D ratio).

Tree condition surveys focus on the health and condition of trees, making recommendations for good tree management based on the physiological and structural condition of the trees and local environmental conditions.

Tree Risk Assessment Explained:

• Tree risk assessment is a systematic process to identify, analyze and evaluate tree risk.
• Risk evaluation is the process of comparing the assessed risk against given criteria to determine the significance of the risk.
• Risk is evaluated by categorizing or quantifying both the likelihood/probability of occurrence and the severity of consequences.
• The risk can then be categorized or calculated and compared to tolerances to determine if the risk is acceptable.

Our team of qualified and experienced arboriculturists will focus on where there is an actual need for tree risk surveys by zoning your land holding based on the levels of usage and/or occupancy.

We can provide assistance with Veteran tree surveys using the Natural England ‘Specialist Survey’ for clients with special trees on historic parkland from small or large estates and land owners, our are designed to help landowners, private estate or organizations minimize the risk of injury caused by trees on their property

It is a legal requirement to maintain your land so that it doesnt harm visitors or trespassers. You may be liable for any damage to property or personal injuries which occur on your land. Which is why being aware of the state of any trees on your land is so important.

What is ash dieback?

• Ash dieback is a fungus that originated in Asia and arrived into the UK prior to 2006 when the fungus attacked UK ash trees including the Common ash also known as European ash. The resultant damage and tree death has been sweeping. The disease is now widespread throughout the UK and Europe. It’s thought that it will affect around 60 million trees in the UK alone. The Woodland Trust estimates that we will lose around 80% of our ash trees in the UK. This is going to have a devastating impact on the landscape and the biodiversity of our woodlands, as well as a major loss in connections between habitats as we lose hedges and individual trees outside of woods. Ash dieback is a fungus spread by spores from infected leaf litter. These spores are then blown to the next tree to infect. Once infected it does not take long for the newly infected tree to show signs and symptoms. The fungus will attack its leaves, get into the tree’s systems and block the water transport system. Trees can then die or become brittle. Whilst healthy trees have a flexibility and bend in the wind, branches and limbs on trees with ash dieback will fracture and snap in the wind.

How do I know if my trees have ash dieback?

• You should contact a qualified arboriculturist to survey and assess the situation. This should take place between July and September as trees need to be in full leaf to give an accurate reading. 
• Our team of trained arboriculturists can undertake Phase 1 surveys during this time. Below is our process for assessing the impact on large estates and large groups. We conduct ad hoc inspections on individual trees and create a treatment and monitoring plan accordingly.

Ash dieback survey process

Phase 1 surveys identify: 

• Areas of significance, levels of infection, clearance impact and classify the percentage of any dieback if found. The clearance impact is important because are moving one tree in a woodland will not have significant an impact on the landscape as removing a lone tree in a field.

Phase 2 surveys identify:

• The number of stems that need to be removed, management plan if appropriate and restocking levels.  Depending on the size of the plot, a Phase 2 survey can also be done at Phase 1 stage, or on a return visit.

After each survey phase we provide a full report with our findings

We can arrange for a full and comprehensive survey of your existing tree stock and provide geo-referenced tree location plans, alongside a detailed tree management plan and recommendations.  For large sites or multiple site owners, an appropriate and proportionate approach to tree risk management can be prepared to maximise the return from your budget.

• Decay is a natural process and does not necessarily mean a tree is unhealthy. However, depending on the extent and type of decay and its position on the tree, it can lead to loss of mechanical strength.
• Using tomography, we can ‘map’ the decay within a tree. Stress waves travel through sound wood faster than dysfunctional wood. So with sensors around the tree measuring the time it takes an impulse to travel through the wood and reach other sensors, we get an impression of the internal condition of a tree.
• Detailed analysis of the tomogram enables us to determine the loss of mechanical strength and quantify the extent of tree work required to reduce the risk of failure.
• There are occasionally circumstances where tomography is unsuitable, such as assessing the extent of decay in buttress roots. In these situations, we use a Resistograph. This  drill measures resistance as it travels through the wood, providing information on the tree's internal structure at the points of drilling.
• Usually, decayed wood has a lower resistance. So with this information, combined with expert arboricultural knowledge of tree species and the fungi involved, we can better understand the likely impact of decay on the tree's structural integrity.
• Data analysis enables us to produce a specification of works if required, to reduce the risk of failure.