A Multispectral Way of Seeing if Bare-Rooted Trees Are Still Alive

Using infrared photography to spot life before the leaves appear

Planting bare-rooted trees always feels a bit like an act of faith.
You put what looks suspiciously like a bundle of sticks into the ground, water it, mulch it… and then wait. Sometimes for weeks. Sometimes for months.

But what if you didn’t have to wait?

🌱 The problem with bare-root trees

In winter or early spring, bare-root trees:

• Have no leaves

• Show no visible growth

• Can look identical whether alive, dormant… or dead

Traditional checks (scratching the bark, bending twigs) are crude and localised. They tell you what’s happening in one tiny spot, not across the whole plant.

That’s where multispectral imaging comes in.

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👁️ Seeing what the eye can’t: Near-Infrared

Healthy plants strongly reflect near-infrared (NIR) light because of the internal structure of their cells.
Dead or stressed plant tissue reflects much less.

Even without leaves, living cambium, buds, and internal moisture can still produce a detectable NIR signal.

Using:

• A multispectral or IR-converted camera

• Or an IR filter (e.g. 720 nm long-pass)

you can compare:

• Visible light → looks lifeless

• Infrared → quietly glowing with activity

In false-colour IR images:

• Living tissue often appears bright red or pink

• Dead wood stays dark or dull

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🧪 Why this works (the science bit)

Infrared reflectance depends on:

• Cell wall structure

• Water content

• Internal air spaces

Even before photosynthesis ramps up in spring, living tissue still interacts with IR light very differently to dead material.

It’s the same principle used in:

• Crop stress detection

• Satellite NDVI vegetation maps

• Drought monitoring

You’re just doing it… in the garden.

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🌳 Practical uses

This approach can help you:

• Check newly planted bare-root fruit trees

• Compare multiple saplings quickly

• Decide whether to wait or replace a failed tree

• Monitor recovery after transplant shock

It’s non-destructive, fast, and strangely reassuring.

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🔍 A quiet reminder

Just because something looks dead…
doesn’t mean nothing is happening.

Sometimes you just need the right wavelength to see it.