The duty of ensuring that any trees on a property, or piece of land, are safe falls on the owner of the land in question. It is essential to ensure that the trees do not present any safety or health risk, if the land is open to the public. To make sure that some trees are safe, bracing may be necessary.
The prescribed method of collecting any accurate information on trees located on a piece of land is a tree survey. Details ranging from the age and species to the location and number of trees are among the data collected during tree surveys. The provisions laid out under BS 5837:2012 are followed if a pre-property development inspection is required for a potential construction site. A tree health survey can also capture other information relating to the health, damage, dimensions, and presence of infestation or disease of the trees under consideration.
A professional tree health survey follows the process described below.
Step 1: Pre-planning
To pick up on certain diseases and infestations, it is important to properly time the survey. No tree should be left out of the exercise, and the entire area must be covered. As such, some level of pre-planning is needed. To apportion a large area into manageable sections, four recognized methods can be used.
- Radius Survey Method – It is best to create a circular survey area covering a set radius, that will be extended bit by bit (by a few metres each time), when surveying large areas of tree cover.
- Complete Survey Method – This method involves covering every tree of a specific species under consideration, making it the most comprehensive survey type.
- Quarter Point Transects Method – In this method you identify a diseased tree and then move in the four cardinal compass directions (north, south, east and west) marking down any other affected trees along the way.
- Line Transects Method – This approach uses a series of evenly spaced transect lines. You check the trees to your left and right as you move along each line.
You will do most of the survey work at ground level. You might need to use the necessary safety equipment in cases where you are required to conduct the survey work from an elevated position, like when you need to inspect the cavities and crowns of trees.
Tree Health Survey Process
You will need to document all the necessary details of each tree, identifying their location and species using tree tags, as you make your way through them. Depending on the type and extent of damage identified, each tree will be defined as poor, fair, or good. The following details will be required:
- Tree Species
- Coordinates of the tree’s location
- Life expectancy and current age of the tree
- Tree’s physical condition including notes on damaged branches and deadwood
- Crown spread and overall size of the tree
- Colour of leaves
- Canopy condition
- Root condition
- Ivy presence
- Fungus presence
- Impact Assessment Preparation
You will make a suggestion on the trees that require removal and the most appropriate ones to be used in replacing them using an AIA (Arboricultural Impact Assessment). You must follow British Standard 5837:2012 when conducting a Tree Constraints Plan and Arboricultural Survey. For readers in Kent, you may want to see ‘tree surveys Kent‘.
Any signs pointing towards a pest or disease infestation in the trees need to be documented in all reports. All parts of a tree can be seriously damaged by a pest infestation. The tree may end up dying or with a weakened structure. It goes without saying that a weakened tree poses a significant safety risk to the general public. Any hidden damage can be detected using sensors and tomographs.