Tree Constraints Plan: what it shows and how it is made

A Tree Constraints Plan shows the surveyed trees on a plan of the site, at a stated scale.²

• Each tree and its number. Leeds City Council asks for tree names and ID numbers on the plan.²
• The BS 5837 category. Plans show the category in the BS colours, green for A, blue for B, grey for C and dark red for U.^{2 3}
• The root protection area (RPA). The RPA starts as a circle centred on the base of the stem. Where roads, walls or other site conditions make root growth uneven, a polygon of the same area can replace the circle.²
• The crown spread. Leeds asks for the RPAs as well as the canopies, not the canopies only.²
• Trees off the site. Trees outside the boundary can affect the site through their crowns, RPAs and future growth.²

Some plans also show the shade each tree can cast. Tree Atlas draws a shading segment from north-west round to east, with a radius equal to the tree height.

The developer and the design team need it, before they fix the layout. Leeds City Council calls a tree survey a pre-requisite before it considers development that affects trees.²

Councils ask for tree information when a planning application can affect trees on or next to the site.⁴ Each council sets its own list in its local validation list, so check with the planning authority.⁴

BS 5837:2012 Table B.1 sets out the tree information for each stage of the planning process. Leeds City Council reproduces it in its guidance. In summary:²

The tree survey records the trees. The other documents use the survey to plan the design and to protect the trees during the work.

Leeds City Council asks for the full tree information, including RPAs, on all the main layouts, including engineering layouts such as drainage.² The architect and engineer draw those layouts in CAD, so they need the trees as CAD data.

Tree Atlas exports a DXF in British National Grid, in metres. It has a layer for each category: TREES_A, CROWNS_A and RPA_A, and the same for B, C and U. It also has layers for the site boundary, shading, trees to remove, groups, woodland and hedges, and notes. Tree Atlas does not export DWG.

Tree Atlas draws the plan from the survey records. You do not draw it by hand.

• Each sheet is A3 landscape, at a standard scale from 1:100 to 1:1250. A large site is split into numbered sheets with match lines and a key plan.
• Trees are placed in British National Grid at true scale. North is grid north.
• Each RPA is drawn dashed in the category colour. It is the rpa-v1 circle, or an adjusted shape of the same area when you record one.
• Each crown is drawn through the four measured spreads: north, east, south and west.
• Labels read category and number, such as A·T1. A TPO tree has a dagger and a veteran tree has a star. Category U and trees to fell have a removal cross.
• Groups, woodland and hedges are drawn with their RPA buffers. The feature RPA rule is marked provisional on the plan.
• The sheet has a key, numbered notes, a scale bar, a north arrow and a title block with the drawing number, status and revisions.

The plan is part of the BS 5837 report PDF, straight after the cover. The web desk also lists it as its own PDF. The plan shows no base mapping at present: survey data only. Use the DXF to put the trees on your own base drawing.

The category letter is printed on every label, so the plan reads in black and white.

Tree Atlas records the survey on site and produces the report, the Tree Constraints Plan, the schedule CSV and the DXF from the same records. It does not produce an AIA, a TPP or an AMS.