Tree Safety surveys are typically carried out by Arboricultural Consultants or by experienced staff that are trained as tree safety inspectors. These people will visit the tree, carry out the inspection and record the results using the Tree Survey or Estate Survey Android™ applications (on their mobile phone or tablet), or the data can be noted down and later entered directly into the OTISS website.

Viewing the Tree Safety Data

The TreeSafety button shows the trees as rows on a table/spreadsheet. Read more about how to sort and filter the data and edit the data. The spreadsheet can be used to select/filter trees, and then various reports can be created.

The survey form can be customised to suit your own working practice and for each individual client’s requirement – see below.

The table (at bottom of this page) lists the data that is recorded for each tree inspection.


Use the Species fields to assign a genus/species by Common or Botanical name. The Variety field allows for further distinctions to be recorded (if required) – enter some text or select from the configurable dropdown list.

If the Structure is a Group, Hedge, Shrubs or Woodland (displayed as either a linear oblong or a polygon), then you can record multiple species with a Variety and NumTrees for each one. The NumTrees for each species are automatically added up and the total stored in the NumTrees field for the group.

OTISS provides several regional lists of tree species (e.g. UK/Europe, Australia, New Zealand, etc.). Each list contains 100s of native and common species for that region. These lists also include entries for the genus (e.g. Willow sp.) for when species level identification is not required. You select the regional list at registration and never need to worry about it again. You cannot add or change these lists – they are shared between all OTISS users.

For each estate, you can build up a list of Estate Tree Species to augment the common species. On the survey forms, the two sets are presented as a single list of species. Use the Estate-> Tree Species website page to configure the species list. New species can also be added when using the OTISS survey apps.

If you find a species that you think should be added to the shared, regional OTISS lists, then please email the details to

Tree reference/tag numbers

When you plot a new tree, OTISS ‘suggests’ a suitable reference/tag number to use. But this is only a suggestion – you can change it to whatever you like! There are three different methods for making this suggestion. Choose the one that best suits your requirements.

  1. Arb Standard – T01, G01, H01, T02, T03, G02, …
  2. Arb Single – T01, G02, H03, T04, T05, T06, G07, …
  3. OTISS Flexible – ABC-001, ABC-002, ABC-003, …

Read more about Tree Numbering…

Measurements – DBH

The DBH (Stem Diameter) recorded EITHER as milli-metres or centi-metres. On the Customise Survey webpage add “(mm)” or “(cm)” in the DBH field name.

Measurements – Crown Spread

The crown spread can be recorded EITHER as a single value OR separate values for North/East/South/West directions. The asymmetric crown can be displayed on the maps pages. On the Customise Survey webpage you can make the Crown Radius field visible (and it will hide the other 4 fields). For other projects, simply make the one of the N/E/S/W fields visible and it will automatically show all four fields (and hide the average crown radius field).

Measurements – Value or Ranges

In most cases, OTISS wants you to enter numeric values for DBH, Height and Crown Radius. OTISS can then chaeck them and use them one scaled maps and drawings.

You can also have a picklist of ranges for the DBH, Height and Crown Radius fields. For example, on the Customise Survey webpage add picklist for Height as “Up to 10m=10, 10m-15m=15, 15m and more=30”. We still store a single number in the database, but you can present it on the survey form and reports as a range.

Survey Notes…

The Description and Survey Notes fields allow for free text entry. But to speed up the survey process we provide a means of quickly entering your commonly used sentences and phrases. Below each field there is another button that allows you to select from a list of commonly used sentences and phrases, these are appended to the text field and can then be modified to suit this particular inspection. You can customise this list of commonly used sentences and phrases via the Customise Survey button on the TreeSafety page – see below.

The Description field is commonly used to describe the location of the tree and for Risk Assessment, anything that may be a target for tree safety purposes. These details tend not to change between surveys.

The three Survey Notes fields are used to describe various aspects about the tree itself – its phsyiological and structural defects, fungus, pests and diseases, etc.


The survey form has three separate Recommendation fields to record what work is required. Each recommendation field has a separate Timescale/priority, so that you can itemise short and long term work/maintenance recommendations. The Timescale fields record your suggestion of how quickly the work should be carried out; e.g. Urgent, 3 months, 1 year, etc. On the Maps page, you can colour code the icons based on when the recommendation/work is due for completion. Read more…

Work Done…

Each of the Recommendations above also have a set of fields that are used to record the work actually carried out. We record the date the work was done, the name of the OTISS user (i.e. who was part of the team who actually did the work – or who did a followup visit to check everything was done) and some work notes. The work notes may be useful when the job was not straight-forward. You can record reasons why all the work was not completed, or why extra work was carried when more issues were uncovered. Read more…

Trees, Groups and Hedges

On the map page, there are separate buttons to allow you to add individual Trees, linear Hedges, Groups of trees.

The Structure field is used to control how an item is displayed (and stored). Individual trees are shown as POINT icons. Groups, Hedges, Shrub and Woodland areas are shown as POLYGON or LINE STRING shapes. Simply select a structure and press press Save – the location co-ordinates will be automatically converted to the required shape.

The location coordinates are shown in the standard Well Known Text (WKT) representation for GIS objects. We don’t expect that you will ever need to edit these coordinates directly. It is recommended to change the shape and location on the Map page. Valid WKT formats are as follows:-

  • POINT (x y)
  • LINE STRING(x1 y1, x2 y2, x3 y3, …)
  • POLYGON ((x1 y1, x2 y2, x3 y3, …, x1 y1)) – NB: the last set of coordinates must be the same as the first.

Risk Assessment

OTISS now supports various tree safety risk assessment methodologies (e.g. ISA 2013, Matheny and Clark 1994, THREATS). As part of each tree inspection, you fill in the risk factors that are used to automatically calculate a resulting risk category. OTISS supports many standard methodologies, and we provide two configurable algorithms to setup your own method. Read more…

Map Icon Colours

The colour of the map icons can be configured based on the data values assigned to some of the survey fields – e.g. condition, work due, customText.

On the Maps page, use the Tree Safety Options panel to (a) select which colour configuration to use, (b) to show the Colour Key/Legend, and (c) the Colour Config button takes you to the TreeSafety Map Colours web page.

The TreeSafety Map Colours web page (also found via the Customise Survey button on the TreeSafety page), is used to setup the required mappings from data value to colour.

Each colour row has: (a) a Display Text that is shown in the Colour Key; (b) a separate Data Value that is used to match with the data; and (c) the map colours to use for the icon and text.

  • The Display Text and the order of the rows in the Colour Key can be changed in any way you want. The little arrows on each row allow you to adjust the order of items so they appear in a sensible order in the Colour Key/Legend.

  • The Data Value determines which colour to use for each tree/item. The ‘~ Other’ data value is used when no match is found – i.e. ‘Otherwise use this colour’.

  • Numeric Data Values will be treated as ranges; e.g. a set of rows with Data Values of 0, 1, 5, 15.5, 30 will match the values 0, 1+, 5+, 15.5+, 30+ respectively. In this case the ‘~ Other’ data value will match any negative numbers.

The Populate Colours button allows you to pick one of the supported fields and it will create/update the colour key for that field. It will search the surveyed trees and add a value-colour entry for all the data values found. You can then use the edit/pen icon on each row to change the icon and text colours.

The Work Due value is calculated as the number of ‘days’ from today until the date the work is due to be completed (i.e. date of the inspection plus the recommended timescale). Different colours can be setup to represent the priority of the required works. For example: GREEN: no recommendations/no work required, RED: work already overdue (negative values), RED: work due within the next year (i.e. 1+ days), ORANGE: work due after 1 year (365+ days)

Survey/Client Templates

OTISS provides a set of standard TreeSafety and Risk Assessment survey forms with all the required fields and a few additional fields that may (or may not) be useful for you. Many people will use our standard survey form, but many users like to customise the survey form (a) to suit their own working practice and preferences, and/or (b) to accommodate a clients’ specific requirements.

We recommend that you setup a survey form that reflects your preferences and use that on all your clients. This is achieved using the ‘Client Templates‘ feature. You can create one or more ‘client templates’. These template ‘clients’ are not used for doing surveys or real projects – they are just an easy/familiar way for setting up and storing your ideal survey forms (and some other settings). Here is what you have to do.

  1. Create a client with a suitable name (e.g. ‘Tree Survey #1’).
  2. Select that client and customise it’s Survey Forms to be your ideal ‘standard’ – i.e. customise the field names, picklists of common values, mandatory fields, etc.
  3. Now every time you create a new a client, make sure to select ‘Tree Survey #1’ in the Client template field. The survey forms (and other settings) will be copied from the selected template.
  4. If required, the new client’s surveys can be customised further – without changing your template.

As you learn more about using OTISS, you can keep returning to the template client and tweaking it to make improvements. Then subsequent new clients will use your newly improved forms, or you can copy the changes into a specific client using the Survey Templates button as described below.

Customise the Survey Form

Each client has its own survey form which can be adapted to accommodate any specific requirements. Customizing a survey form for one client does not change the survey forms for your other clients. You can customise most of the fields on the survey form via the Customise Survey button on the TreeSafety page – i.e. all fields except those field marked with a * in the table below.

Edit each field to customise the following:-

  • Each field has a ‘Field Id’ which is what OTISS uses (internally) to identify each field on the survey form and when generating reports.
  • The field’s ‘name‘ is what actually appears on the survey forms and reports. You can change the Field Name. A shorter name is suitable for columns in tables and spreadsheets, whereas a more informative name can be used on the survey forms.
  • A picklist of common values will speed up data entry on the mobile devices. This can be ‘suggestion’ list where you pick an item from the list but can also entry a value manually; or you can tick the “Value must be one of the list below” box, which means that you can only select from the list (i.e. manual entry is not allowed). It may be worthwhile adding ‘not applicable’ or ‘not recorded’ to the picklist for when an actual/sensible value is not appropriate.
  • Set some fields as mandatory so that you do not forget to provide a value when filling out the survey form.
  • Hide any unwanted fields to make the survey forms shorter and uncluttered.
  • You can configure minimum and maximum values for the numeric fields.
  • Use the up/down arrows to change the order of the fields on the Android survey apps. Note: only the Android survey form is changed – the web version of the survey form is unchanged (for now).

With the Survey Templates button, you can copy a survey that you setup for a different client or from one of your client templates. Use that as a starting point and then modify it further as required for this client.

Any suggestions?

OTISS is constantly developing to suit our users’ requirements. Please contact us if you have suggestions for features or options that you would like to see.

Tree Safety Data Fields

Survey & Site * Each inspection is carried out within a Survey. The Survey dictates the site for this tree.
LocationThe location – stored as longitude/latitude in the GIS database. Also displayed as national grid references.
Reference * A reference name or number. e.g. T01, G14.
Reference2A TPO number, other reference(s) or tag number.
SpeciesA species selected from a list of tree species. The Common Species and the Estate Species are are presented as a single list. If the Tree Structure is a Group, Hedge, Shrubs or Woodland, then you can record multiple species and a variety and numTrees for each one.
VarietyA variety or cultivar (text).
DescriptionA detailed description of the tree. For example: its general structure, its location, potential targets at risk, etc. This information tends to be unchanging between inspections.
Tree StructureOne of: Tree, Multi-stemmed tree, Group, Hedge, Stump, etc. This field determines whether the icon is a point or a polygon.
Life Stage (Age Class) One of: Newly Planted, Young, Early Mature, Mature, Over Mature, Veteran.
Life ExpectancyEstimate life expectancy or “remaining contribution” in years, e.g. 10+, 20+, etc.
Number of StemsNumber of stems in a multi-stemmed tree.

If the Structure is a Group, Hedge, Shrubs or Woodland, then the NumTrees for each species are automatically added up and the total stored in the this field for the group.
Inspection CycleHow long before this tree should be inspected again, e.g. 1 Year, 2 Years, 5 Years, etc.
ConditionA summary of the overall condition: good, fair, poor, dead
pConditionA summary of the Physiological Condition: good, fair, poor, diseased, dead
sConditionA summary of the Structural Condition: good, fair, poor, collapsing, decaying
HeightA measurement or estimate of the height in metres.
DBHA measurement or estimate of the DBH in centi-metres. DBH means the diameter at breast height 1.5m. You can use this as milli-metres – just change the label.
Crown RadiusA measurement or estimate of the average crown radius in metres.
Crown Spread: N/E/S/WComing soon! A measurement or estimate of the crown radius in metres in the four compass directions. This allows an asymmetric crown to be displayed on the map.
Survey Notes1
Survey Notes2
Survey Notes3
Detailed notes of what was seen during this inspection. Three separate multiline text fields.
Risk AssessmentFour configurable riskFactor fields to record risks and a configurable riskCategory to show the final result. Alternatively, all five fields can simply be customised as extra fields in your survey – in exactly the same was as the other custom fields.
Recommendation 1
Timescale 1
WorkDone 1
A set of recommendations for maintenance work or further inspections required. A timescale for these recommendations, e.g. No Action, Urgent, 6 Months, 1 Year, 2 Years, etc.

During any follow-up work, you can use the WorkDone fields to record when, by whom and some notes about what work was actually carried out. These WorkDone fields are often hidden whilst doing the surveying, and then made visible for the follow-up work.
Recommendation 2
Timescale 2
WorkDone 2
Another set of recommendations for maintenance work or further inspections required. As above… These fields are often hidden if you only want to have one set of recommendations.
Recommendation 3
Timescale 3
WorkDone 3
Another set of recommendations for maintenance work or further inspections required. As above… These fields are often hidden if you only want to have one set of recommendations.
CustomText1A configurable text field (max 50 letters).
CustomText2A configurable text field (max 50 letters).
CustomText3A configurable text field (max 50 letters).
CustomNum1A configurable decimal number.
CustomNum2A configurable decimal number.
CustomNum3A configurable decimal number.
Date Inspected * The date on which the item was inspected.
User Name * The name of the person who carried out the inspection.
RemovedWhen an item is ticked as ‘removed’, then it will no longer appear on the maps or reports showing the ‘most recent’ survey data for that site. The previous survey data is retained, and can be seen when a specific survey is selected.