Specifying replacement trees that actually survive

A replacement tree specification that produces a living tree in ten years is mostly about three things: matching the species to the site, choosing a stock size the site can support, and paying for aftercare. Most planning conditions requiring replacement planting say almost nothing about any of them, which is why so much conditioned planting is dead within three summers. The British Standard on trees from nursery to independence in the landscape sets out what a specification should cover, and using it as the spine of your submission makes the condition dischargeable and the tree likely to survive.

Matching species to soil, exposure and space

Start with the constraints rather than with a wish list. Soil pH and texture, drainage, exposure to wind and salt, the space available above and below ground, and the proximity of buildings, drains and services all narrow the field before aesthetics comes into it.

Two errors recur. The first is planting a large forest species in a space that will never accommodate its mature canopy or its rooting volume, which produces a tree that is topped or removed within twenty years. The second is choosing a single species for a whole scheme, which is efficient to buy and vulnerable to one pest or disease arriving.

Where a condition requires replacement of a particular tree, check whether it specifies a like for like species or leaves the choice open. If the original was in poor condition because the species was wrong for the site, say so and propose an alternative with reasons. Officers accept that argument when it is made with evidence rather than convenience.

Biosecurity is worth a sentence in the specification. Ask for stock grown in the country of planting where possible, request evidence of plant passporting, and inspect on delivery.

Stock size and why the biggest tree is rarely best

Nursery stock runs from whips and transplants, through feathered trees and standards, to heavy and extra heavy standards and semi-mature trees. Larger stock gives instant effect. It also carries a smaller proportion of its root system, takes longer to establish, needs far more water, and is far more likely to fail.

A standard planted alongside an extra heavy standard will often be the larger tree within ten to fifteen years, because it establishes quickly and puts its energy into growth rather than survival. Where a condition specifies a minimum girth, that is usually a planning judgement about visual effect rather than an arboricultural one, and a case for smaller stock with better establishment can be made at discharge stage.

Planting season and handling on site

Bare root and rootballed stock is lifted and planted during dormancy, roughly November to March. Container grown stock can go in at other times but needs irrigation to survive its first summer.

But the window is shorter than the season suggests. Planting into waterlogged or frozen ground damages soil structure and the roots, so the practical opportunity is the dry spells within the dormant period.

Handling is where good stock is ruined:

1. Order early and agree a delivery date matched to the ground being ready, not to the nursery's convenience.
2. Protect roots from wind and sun in transit and on site, keeping bare root material covered and moist at all times.
3. Heel in immediately if planting is delayed by more than a day or two.
4. Plant at the same depth the tree grew at the nursery, with the root collar visible at finished level.
5. Backfill with the excavated soil rather than an imported rich mix, so roots move out into the surrounding ground.
6. Firm without compacting, and water in thoroughly at planting even in wet weather.

Point four causes more losses than any other single error. A tree planted 100 millimetres too deep, then mulched over the collar, will decline slowly and nobody will connect the cause to the effect.

Staking, guards and mulch specification

Staking is support for the root plate, not for the stem. A short stake, roughly the lower third of the stem height, driven outside the root ball and tied with a single adjustable tie, lets the stem flex and thicken while holding the roots still. Tall stakes tied high produce a tree that snaps when the stake is removed.

Specify removal. A stake left for a decade girdles the stem, and the tie is the thing that kills the tree. Two to three years is normal, and the specification should say who checks and when.

Guards depend on the threat. Spiral guards deal with rabbits, mesh guards with deer, and a full cage with livestock or vandalism. Each has a removal date too.

Mulch is the cheapest effective measure available. A layer of composted bark 75 to 100 millimetres deep over a circle around the tree suppresses grass competition, holds moisture and moderates soil temperature. Keep it clear of the stem by a hand's width. Grass growing to the trunk is a bigger constraint on establishment than most people expect.

Aftercare, watering and the establishment period

Establishment takes years, not months, and the standard planning condition requiring replacement of failures within five years is effectively a maintenance obligation for that period.

Write the watering regime into the specification with volumes and frequency rather than as an instruction to water as necessary. A regime that specifies a stated volume per tree at a stated interval through the growing season, for the first two or three seasons, with a trigger for additional watering in dry spells, is something a contractor can price and a client can check.

Also specify:

• Weed-free maintenance of the mulched circle, by hand or by approved treatment, for the establishment period.
• Annual inspection of ties and stakes with adjustment or removal.
• Formative pruning in the first years to establish structure, done at the right season for the species.
• A written record of watering and inspections, dated.

That record is the document that protects you if the council serves a breach of condition notice in year four. Losses happen. And losses with a maintenance log look like bad luck, and losses without one look like neglect.

Wording the specification for a planning condition

Discharge is easier when the submitted document maps onto the condition. Include a schedule listing species, stock size and form, quantity, planting positions cross referenced to a drawing, soil and pit preparation, staking and guards, mulch, and the aftercare regime with its duration.

Reference the British Standard on tree establishment in the specification rather than reproducing it, and state the planting season in which the works will be carried out. Where the condition includes a replacement clause, restate it so the contractor and the client both know the obligation runs beyond practical completion.

The Landscape Strategy submitted with the application is the right place to establish the planting principle and the species palette, with the detailed specification approved later at discharge. Where existing trees are being removed to make way for the new planting, the Tree Survey prepared to BS 5837:2012 provides the baseline the council will compare against.

This is general guidance, not legal advice, and condition wording differs between authorities, so check the requirements with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.

Browse the report types on PlanScope if you are putting together the landscape evidence for a small site.