When a decision-maker requests a 'tree survey', typically to support a planning application, do you know what should be included as part of the requested survey? Well, based on our experience, we believe most environmental practitioners are not aware of the specific detail surrounding 'tree surveys' and what they should comprise.
Generally speaking, tree surveys can be divided into two distinct categories - Basic Tree Survey & Inspection and Detailed Tree Survey. Regardless, it's important that each respective survey type (including bespoke tree surveys) should only be undertaken by a suitably trained and qualified professional. So if there is any doubt, then ask the respective individual to produce evidence of their experience and qualifications.
This week's blog focusses on Basic Tree Survey & Inspection. But, do you know what's involved with this simplest form of tree survey? Well, quite simply, it’s a ground level visual assessment of individual and/or groups of trees within a site. In addition to gathering physical data such as tree height, the key purpose of the survey is to recognise and report on hazardous trees.
As with any site work, prior to undertaking a site visit, it's important to establish the limits of the survey scope with your client, in terms of the information they need to inform their decision-making process. In addition, it is also advisable to ensure that your client has arranged all the necessary land access to a site and wider study area, and that all related health and safety considerations have been assessed, including a requirement for any necessary PPE.
A Basic Tree Survey & Inspection should take cognisance of relevant legislation, applicable local, regional and national planning policy and good practice guidance, for example, British Standard 5837 (2012): Trees in Relation to Deign, Demolition and Construction - Recommendations.
A Basic Tree Survey & Inspection should seek to record information that is relevant, factual, consistent and accurate. It is important to note that while the ‘tree survey’ aspect of the survey gathers factual information e.g. tree location or height, the ‘tree inspection’ aspect of the survey gathers information that is opinion based e.g. tree condition and/or life expectancy.
As with a Preliminary Ecological Appraisal, a desk study should be undertaken prior to completion of a site visit. The desk study should comprise a search of publicly available information sources to provide an understanding of the arboricultural context of a site, for example, relevant tree and woodland planning policy, proximity of ancient woodland and presence of Tree Preservation Order (TPO) trees and/or areas.
When it comes to assessing trees as part of a site visit, what parameters should be recorded by the surveyor? Well, the answer to the question is that it varies for each site because it depends on the species, age and number of trees present, coupled with the prevailing ground conditions within a given site. Generally speaking, for each tree, the survey should seek to record the presence and provide a description of the following:
crown density and any evidence of crown die-back
dead wood, hanging or broken branches;
cracks, splits and damaged branches;
holes and/or cavities;
swelling in branches or the main tree stem;
damage to the bark;
fungi on tree branches, stem and roots;
damage to tree roots; and
cracks in the soil around the trees roosts.
Where appropriate, individual trees can be photographed and/or tagged as part of a site visit using a small numbered metal disk or a more expensive arboricultural plastic tree tag.
The resulting report should describe the purpose of the survey, applicability of relevant legislation, planning policy and good practice guidelines, and provide a description of the baseline conditions established by the desk study and field survey. In addition, the report should also provide a description of any required action along with an indication of priority. Unless the survey did not establish the presence of trees within a site, the report should be accompanied by a tree plan presented on a 1:10,000 OS digital base, which should show the location and ID of each tree recorded within the survey area and where applicable, delineated root protection zones.
Image Credit: TETRIX Ecology & Pixaby User (ID: Baba Mu & 127071)