Trees of Bristol   Sites   Species   Collections   Search   Photos   About   Help  


Tree data collection

These notes are intended to help in the collection of data for inclusion in the website https://bristoltrees.space.
Data for the site can be provided in spreadsheet format if available from existing systems. We have to load each new source of data separately and this allows us to adapt and change the data to fit but it is much easier if the data is close to what we hold.
Mobile capture of this data is under development but is not yet robust enough for general use. In the meantime, new data can be collected and recorded on a spreadsheet and sent to the webmaster. You can find a template (as CSV) : save and open in your favourite spreadsheet program eg OpenOffice. The three rows show the headings,the units and an example.
The blog post Tree data standardization provides some background discussion.

Fields

Identifier

Each tree on the site needs a unique identifer. To ensure uniqueness across multiple sources of data, a binomial identifier is used, comprising a domain identifier followed by an identifer which is unique to that domain. For Bristol City Council, we use a prefix of BCC and the asset number used by BCC to create a combined identifier e.g. BCC-33528. The domain identifier can be added during data loading or included in the source data. Because of the way identifiers are used to create a unique page reference for every tree, the characters used in the domain identifier are restricted to upper and lowercase letters, digits, full-stop, hyphen and underscore. It may be convienient for data collection purposes to structure this code by creating a prefix for an area such as a park, or for each surveyor and then numbering trees within that prefix.

Species name

It is good to be able to identify the species of the tree as accurately as possible. We use the latin or botanical name of the tree as the prime name with common name being used for confirmation. The format of botantical names follows standard nomenclature in the way Genus, species, varieties, cultivars and forms are written. The RHS guide is useful (although not all forms are recognised in BristolTrees). Please see the list of names of all species currently in BristolTrees. Whilst it is good to be as precise as possible, at least Genus and species should be provided. Care is needed in writing the latin name since they are easy to misspell. However corrections can be made when the data is loaded.
The common name of the tree can also be added. If the latin name is unknown, this will be used to find the botanical name but it is sometimes ambiguous so the botanical name is preferable.

Location

The geographic location can be given in several formats : latitude/longitude; easting/northing; OS grid reference. The database stores the location as latitude and longitude and can convert from the other forms if needed. However if using a smartphone to gather locations, this will normally be given as latitude/longitude. A precision of 6 decimal digits is sufficient to place a tree with 1 metre accuracy, which will exceed the the accuracy of the smartphone. It is possible to check and amend the location after loading with reference to Google Map imagery.
Trees are also located in a wider geographical area such as a park or street. The site name should be provided with a site code if there is one in common use.

Tree dimensions

Dimensions change over time so it is important to know when the measurements where made. Accuracy here is not important so this date will be set to the date of uploading if not given.

Girth

Girth is the easiest dimension to take and there is guidance especially on the way to handle tricky situations. In Bristol Trees we measure the girth in centimeters. This is suffciently precise and can be easily measured with a long flexible tape measure. Aboriculturalists use DBH (Diameter at Breast Height) but direct measurement requires a specially calibrated tape measure and in any case, conversion between the two is simple.

Height (optional)

Height is harder to measure but smartphone apps have proved useful here. However it is difficult to be accurate.

Width (optional)

This is the average width of the tree canopy in meters

State

A code indicating the current state of this tree/or tree site: Tree;Stump;Tree pit;Dead Tree; Group; Sculpture; Tree to be planted
For a new tree survey, State will generally be 'Tree' but other values may occur.

Date of Planting (optional)

This may be known when it has been recently planted or a commemorative tree. Date format is dd/mm/yyyy

Form (optional)

This records the form of the tree eg pollarded, lapsed pollard. Terminology in BristolTrees has not yet been standardised.

Condition (optional)

This records the general condition of the tree - damaged, fungal infection etc

Description (optional)

This records any notable features of this tree, for example if it is commemorative, newsworthy or especiailly loved. A tree may be also be species champion in its county, or display particular uncommon features for its species, or be growing in a unique manner or location.

Photos

Photos can be added to the site after the base data has been checked and loaded. If you are taking photos during the survey, make sure that you have a record of the tree identifier used so that the photo can be attached to the correct tree.