Does it work for laid hedges or recently coppiced hedges?

Yes for both. A newly-laid hedge measures very low porosity (the laid stems block most of the gaps) and that's the correct figure — it tells you the hedge is in early Building stage of the Adams cycle. A recently-coppiced hedge measures very high porosity (almost no structure) and that's also correct. The number is meaningful in context with the management history. The questionnaire captures that context for the report.

§ Method

How to photograph a hedgerow for porosity analysis

Published 6 May 2026 · 7 min read · Field technique

Hedgerows look easy to photograph — they’re short, you can walk up to them, and a phone gets the job done. The catch is that most hedges don’t live in tidy isolation. They share the background with the next hedge over, the field beyond, the road, the sky on a half-cloudy day. Get the framing wrong and the algorithm counts the wrong dark pixels.

This guide is the capture half of the method for hedgerows. It pairs with the measurement method (which is the same physics whichever vegetation type you point it at) and the shelterbelt capture guide if you also work with taller belts.

What you will learn

Where to stand and how far back — numbers for hedge heights
Which lighting conditions help and which make the result unreliable
Phone camera settings and which modes to avoid
How to handle the second-hedge-in-the-background problem
The five capture failures the algorithm cannot rescue
Whether season (in-leaf vs bare) changes the figure

Standing position

Perpendicular to the hedge. The line from camera to hedge should cross the hedge’s running direction at a right angle. Stand back 2–3 hedge-heights, measured horizontally. For a 2-metre stockproof hedge that is 4–6 metres back. For a 4-metre mature hedge, 8–12 metres. Closer than 2 H and the hedge fills too much of the frame, with no sky visible above. Further than 3 H and you start picking up foreground crop, grass, or another fence in the bottom half of the frame.

The camera should be held level. Tilt introduces trapezoidal distortion — the hedge appears wider at the bottom of the frame than the top, or vice versa. The analysis measures vertical slices through the hedge, and a trapezoidal projection biases the per-slice porosities systematically. The bubble level on a phone camera (most do this when you point it forward) is fine.

Aim the camera at mid-hedge height. Roughly 50–70% of the frame height should be the hedge itself, with a thin strip of sky above (10–25%) and as little ground below as you can manage (10–25%). The ground will be masked off in analysis, but less masking is better than more masking.

Light

Evenly overcast is ideal. A uniformly bright sky is the perfect background against which a hedge silhouettes cleanly — no colour cast, no directional shadows, no hot spots on the canopy, no deep sub-canopy shadows that look like gaps but aren’t. The measurement at 10:30 on a grey Tuesday is cleaner than the measurement at noon on a clear June day.

If you must shoot in direct sun, keep the sun behind you. Front-lit hedges show structure clearly, and the analysis handles the shadowed far side correctly. Back-lit hedges (sun behind the hedge) can work for thick stockproof hedges but are treacherous for laid or gappy hedges, because sunlight through the gaps creates bright spots that the algorithm reads as extra sky — porosity inflates by 5 to 15 points. Side-lit hedges are the worst case.

Avoid the first hour after sunrise and the last hour before sunset. Low-angle light creates long shadows through the hedge that look like structural gaps, so the porosity reads high.

Phone camera settings

The default 1x main camera on any modern phone is the right tool. Zoom optical lenses (2x, 3x) are also fine if you stay within their sweet spot. Two things to avoid:

Ultra-wide (0.5x). The edge distortion adds 5–10 percentage points to porosity readings near the sides of the frame. Always crop or recompose to use the main lens.
HDR, Night mode, Portrait mode, Scene Optimiser. These apply non-uniform tone mapping or selective sharpening that distorts canopy edges. Plain camera app, default exposure, highest JPEG quality.

The second hedge behind the first

The single most common capture failure on UK farms. A neighbouring hedge in the next field over appears in your photograph as dark pixels where the sky should be. The analysis counts those dark pixels as part of the subject hedge and undercounts porosity, sometimes by 10–15 points.

The fix is an angle change, not a post-processing step. Walk along the hedge until you find an angle where open sky is visible behind it for the whole length of frame. If you can only find a clear-sky angle for part of the hedge, shoot only that part, mark the rest as not-yet-measured, and come back another day from the opposite side.

Roads, woodland edges, and farm buildings cause the same problem. The rule is simple: sky must be visible through every gap you want measured.

Foreground and ground

Hedgerows usually have grass, stubble, or a margin strip right at their base — a much closer ground line than a shelterbelt typically has. Three things help:

Stand at the right distance. The 2–3 hedge-height rule keeps the ground line in the bottom 20–30% of the frame, where the analyser’s ground-cutoff mask handles it cleanly.
Avoid tall foreground crops. Mature OSR, barley, or maize between you and the hedge intrudes into the bottom of the frame and biases the measurement low. Shoot from a track, margin, or the field side rather than across a tall crop.
Move the cutoff slider in analysis. If a photograph has more grass than usual at the base, the per-image cutoff control lets you mask it out without affecting the rest of the batch.

Five capture failures the algorithm cannot rescue

Background hedge. Already covered — the fix is angle change, not editing.
Motion blur. Handheld on a windy day below 1/250s shutter. Silhouettes soften, porosity reads high. Steady the camera against a gate post or bump the ISO.
Side-lit canopy. Low-angle sun from one side produces bright and shadowed halves the algorithm reads inconsistently.
Tilted horizon. The hedge appears trapezoidal. Use the phone’s level indicator.
Ultra-wide phone lens. 0.5x mode inflates porosity at the edges. Always shoot with the 1x main lens.

Season — in-leaf or bare-branch?

Both are valid measurements but they describe different things. Summer in-leaf captures show the porosity that matters for shelter, biodiversity, and wind reduction in the growing season. Winter bare-branch captures show the structural porosity — the skeleton of the hedge, with all the gaps that the leaves were hiding. For grant-evidence work and Adams-cycle lifecycle classification, summer in-leaf is the standard. For deciding when to coppice or gap-up plant, winter is more diagnostic.

Whichever you pick, be consistent. Year-on-year tracking of a hedge only works if you photograph it in roughly the same season each time. Tag the season in the filename or notes when you shoot.

A reproducible field protocol

A working protocol for a routine farm hedgerow inspection:

Conditions: overcast, mid-morning to mid-afternoon, no rain on the lens
Camera: phone main lens (1x), no HDR, no Scene mode
Stand perpendicular, 2–3 hedge-heights back, camera level
Frame: hedge fills 50–70% of frame height, narrow sky strip above, minimal grass below
One frame every 5–10 metres of hedge length, walking the whole side
Tag each frame with GPS (most phones do this automatically)
Note the season (in-leaf vs bare) and last management date in a notes file
Import as a batch to the analyzer in hedgerow mode

Doing this consistently produces a time series that supports Adams-cycle progression, gap-up planting decisions, and SFI compliance audits without any extra fieldwork.

Run your hedge captures through the analyzer

The per-photo quality scoring will tell you which frames survived capture and which to reshoot. Drop a folder in and see.

Try the hedgerow analyzer →

Frequently asked questions

How is photographing a hedgerow different from a shelterbelt?

Hedgerows are shorter (typically 1.5–4 metres vs 8–15 metres for shelterbelts), denser at the base, and usually have grass or crop right against the bottom of the hedge rather than open ground. The capture rules are the same in spirit (perpendicular, level, sky behind, multiple frames), but the working distances are smaller (5–10 metres back rather than 15–30) and the ground-mask cutoff is more important because the bottom of the hedge usually touches the grass or stubble line.

Do I need a drone for hedgerows?

Almost never. A phone at chest or waist height covers a hedge of any normal height. Drones earn their keep on shelterbelts taller than about 5 metres where standing-on-foot framing breaks down. For hedgerows under that height, the phone is faster, simpler, and produces equally accurate measurements.

What if the field behind the hedge has another hedge in it?

This is the single most common capture mistake on UK farms. A second hedge behind the subject hedge appears in the photograph as dark pixels where the sky should be, and the analysis counts those dark pixels as hedge material. Porosity reads low by 10–15 points. The fix is to walk along the hedge until you find an angle where open sky is visible behind it for the full length of frame.

How tall does the hedge need to be?

Anything from a recently-trimmed metre-high stockproof hedge up through a 4–5 metre tall mature hedge works. The main constraint is that the photograph needs sky visible above the hedge.

Does the season matter?

Yes. In-leaf summer captures and bare-branch winter captures of the same hedge produce different porosity numbers because what’s being measured is different. For grant evidence and Adams-cycle classification, summer in-leaf is the standard. For management decisions, winter bare-branch shows structural gaps more clearly.

Does it work for laid or recently coppiced hedges?

Yes for both. A newly-laid hedge measures very low porosity (the laid stems block most of the gaps) which is the correct figure for an early Building-stage hedge. A recently-coppiced hedge measures very high porosity (almost no structure) which is also correct. Context matters, and the questionnaire captures that.