Have you wondered how are your trees categorised in a Tree Survey? As part of all our tree surveys (or any survey that is completed to the British Standard 5837:2012), we categorise trees into one of four categories.
Category A
Category A trees are trees of high value. These trees are good examples of their species – they may be particularly visually impressive, be good habitats for birds or other wildlife or have other ecological or conservation value. Category A trees (especially when there is a high concentration of Category A trees in a small geographic area) are most likely to be subject to a Tree Protection Order. Tree Protection Orders can also cover a geographic area instead of being applied to a single tree and a high concentration of high-quality trees is likely to lead to a blanket TPO being applied to that area.
Category B
These are trees that are of moderate value. These trees are generally healthy and have some material or conservation value.
Category C
If a tree is Category C, it is of low value. These trees may offer some landscaping or visual benefits but are trees that have low growth potential or are not suitable for the local environment. These trees may be foreign varieties that have failed to thrive, or trees that are overmature and at the end of their life. All young trees are automatically categorised as category C trees; however, a comment should be made confirming this, so these trees are not accidentally removed.
Category U
Category U trees should be removed straight away – these are trees with irremediable defects, structural weakness, trees with infectious pathogens, trees that are inhabited by pests or trees that are already dead.
These four categories are used to provide a quick, easy way for you to assess the health of your trees. By having an assessment of your trees completed, you can complete a health-check on your trees and ensure that they remain healthy instead!
Why not find out more about ProHort’s Tree Survey service by visiting our services page?
Arboricultural Impact Assessment vs. Arboricultural Method Statement
Arboricultural Impact Assessments (AIAs) and a Arboricultural Method Statement (AMSs) are both documents that you may be required to provide at various stages during your building project. Both have slightly different functions, so read on to see which one you may require.
Arboricultural Impact Assessment
This document is often produced during the early stages of a project. Also, this discusses the planned works and the impact that they could have on the trees. This document is often submitted along with a tree survey before an exact working methodology has been formulated. The council, or any other bodies, are allowed to make an informed decision as to what is required. An AIA may also contain a draft AMS.
Arboricultural Method Statement
This document is a site-specific, project-specific method statement which details the exact measures that any contractors should follow whilst completing construction work on site. It is often issued as work is about to commence and will be issued to a foreman or site manager as is applicable. This document is normally requested by your contractor a couple of weeks before the work begins. AMS documents can be relatively generic, but if you have any protected trees, site specific requirements, or if you were using particular methods of construction then you may need to produce this document.
Which one do I need?
It depends which stage your project is in – if you are in the planning stages, we would recommend an AIA. This would identify any site issues which may lead to you commissioning a more detailed AMS as a result of the AIA. If your work is about to commence, and you are concerned about the health or status of a particular tree, then you may need to investigate an Arboricultural Method Statement.
Have you wondered what is ground heave? Ground Heave can have a long-term effect on any building work taking place, make sure you know how to remedy it.
What is Ground Heave?
Ground heave is the upward movement of soils which can occur at any stage of the building or development process. Ground heave is usually associated with clay soil which swells when wet. This then rises upwards – the effect is almost exactly the opposite of subsidence. Despite the actual ‘heave’ often being relatively small (less than 150mm), this can have a long-term effect on any building work taking place.
How do you know it is there?
Signs of ground heave can include vertical cracking to brickwork and windows (if the cracking is diagonal, this may be subsidence). It may also be evident through door frames warping so they are ‘not square’ and paths and patios lifting from their originally laid level.
What causes Ground Heave?
Ground heave is most commonly caused by the removal of established trees. As the roots die away and no longer draw water from the soil, the soil retains more water and will swell when wet. A soil analysis (to analyse the consistency of soil) or a tree survey (to identify the root protection areas of any established trees) can stop the problem developing before it begins.
Other causes of ground heave include soil being removed during excavation, a change in the level of the water table or broken drains. Nearby building works impacting ground drainage, extreme weather conditions or trapped water in the soil freezing and causing the soil to expand can also cause ground heave.
How can Ground Heave be Stopped?
As mentioned above, potential issues with ground heave can often be identified via a soil analysis or tree survey (including an arboricultural method statement if extensive building work is taking place). To stop ground heave, the root cause first needs to be identified and remedied. Once this has been done, depending on the severity of the heave, foundation work will need to take place – reaching down to sub soils that have not been affected by the heave. This can often be costly, as well as causing delays to projects. Advice should only be taken in consultation with a surveyor, who can fully assess the site in question.
Brackets (or bracket fungi) are fungi which appear on trees throughout spring, summer and autumn.
The dangers of fungal brackets:
The fungal bracket will have grown into the heartwood of the tree, which can cause severe weakening of the tree. If the tree has grown weak, it may topple at any time (and not necessarily just when the fungi is present).
How to identify fungal brackets:
The main identifier of bracket fungi is the large bracket body which will appear on the outside of the tree – these can be up to 60cm in diameter. By the time the bracket appears, there will usually have been significant decay inside the tree. A secondary identifier is falling branches, which shows that the heartwood has weakened. However, please be aware that many different factors may also cause the branches of a tree to fall.
What can be done about Bracket Fungi?
Unfortunately, once you have identified bracket fungi, there is often very little that can be done to save the tree. Chemical treatments will also have minimal impact. Bracket fungi enters the heartwood via any open wound or tear in the tree’s trunk – due to this, infestations of the fungi can spread quickly. Ash, beech and prunus trees are especially susceptible.
What to do if you think you have fungal brackets:
If you suspect that your tree has bracket fungi, we recommend that a tree survey is completed as soon as possible. This can help identify any weakness in the tree as well as ascertain whether the fungi present is bracket fungi or another fungi entirely. Regular tree surveys can also identify any wounds on trees, meaning that any susceptible trees are removed before the fungi can take hold.
Prohort Ltd provides comprehensive tree surveys to the BS5837-2012. Find out more about our tree survey service in our Services page.
Have you wondered how are your trees categorised in a Tree Survey? As part of all our tree surveys (or any survey that is completed to the British Standard 5837:2012), we categorise trees into one of four categories.
If a tree is Category C, it is of low value. These trees may offer some landscaping or visual benefits but are trees that have low growth potential or are not suitable for the local environment. These trees may be foreign varieties that have failed to thrive, or trees that are overmature and at the end of their life. All young trees are automatically categorised as category C trees; however, a comment should be made confirming this, so these trees are not accidentally removed.
This document is often produced during the early stages of a project. Also, this discusses the planned works and the impact that they could have on the trees. This document is often submitted along with a tree survey before an exact working methodology has been formulated. The council, or any other bodies, are allowed to make an informed decision as to what is required. An AIA may also contain a draft AMS.
