---
title: Cambium: The Thin Layer That Grows a Tree
url: https://battleborntreeservice.com/glossary/cambium/
business: Battle Born Tree Service
address: 6301 US Highway 50 East, Carson City, NV 89701
phone: 775.232.8243
hours: Office Monday-Friday 8:30 am-5:00 pm; phones answered seven days a week; 24-hour emergency service
credentials: ISA Certified Arborist WE-11728A on staff; Nevada Business License # 20131580674; fully insured
type: Tree service (removal, crane work, pruning, stump grinding, defensible space, snow removal, firewood)
---

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- Cambium

# What is the cambium?

The cambium is a thin layer of actively dividing cells between the bark and the wood. Each growing season it adds new wood inward and new bark outward, which is how a trunk gets thicker.

## Why it matters

Water moves up the tree through the outer layers of wood, and sugars made in the leaves travel down through the inner bark. The cambium sits between the two. Damage it around the whole trunk and the tree is cut off from the roots; damage it on one side and that side dies back. This is why a strip of bark removed from a trunk can be fatal and why a mower or string trimmer scar on a young tree is serious.

The cambium is also what seals over wounds, by growing [woundwood](https://battleborntreeservice.com/glossary/woundwood/) at the edges of a cut.

## Why it matters in Northern Nevada

Winter sun on a smooth, thin-barked trunk and cold nights can split the bark on young trees. Rodents and deer chew bark in snowy years. Mowers, trimmers and vehicles scar trunks near the ground. All of these are cambium injuries. Aspens have particularly thin, living bark; see [quaking aspen](https://battleborntreeservice.com/tree-guide/quaking-aspen/).

Pine beetles feed in the cambium region, which is why attacked pines can go from healthy to dead so quickly. See [bark beetles in pines](https://battleborntreeservice.com/tree-guide/bark-beetles-in-pines/).

## What an arborist does about it

When a tree has a trunk wound, the arborist checks how far around it goes. A scar covering a third of the trunk is a different problem from one that circles it. Tidy cuts to the edge of a wound are sometimes done, but the advice for owners is to protect the trunk at the base from equipment and to call before the wound is old. If the cambium is dead all the way round, no pruning will bring the tree back, and the options come down to monitoring or removal. A fresh scar on an otherwise good tree is worth a call while the damage is easy to measure.

### Sources

- [International Society of Arboriculture, Trees Are Good: Pruning Mature Trees (brochure)](https://www.treesaregood.org/Portals/0/siteContent/pdf/Web%20TAG%20brochures/TAG_CBweb_Pruning%20Mature%20Trees_v3.pdf) (read October 17, 2026)

### Talk to the office

[775.232.8243](tel:775.232.8243)

| Monday to Friday | 8:30 am - 5:00 pm |
|---|---|
| Saturday and Sunday | Office closed, phones answered |

Phones answered seven days a week. 24-hour emergency service.

[Free estimate](#quote)

### Keep reading

- [Arborist glossary](https://battleborntreeservice.com/glossary/)
- [Bark beetles in pines](https://battleborntreeservice.com/tree-guide/bark-beetles-in-pines/)
- [Drought stress and dieback](https://battleborntreeservice.com/tree-guide/drought-stress-and-dieback/)
- [How to tell if a tree is dead or dying](https://battleborntreeservice.com/guides/is-my-tree-dead-or-dying/)

## See also

[Climbing spurs](https://battleborntreeservice.com/glossary/climbing-spurs/) [Woundwood](https://battleborntreeservice.com/glossary/woundwood/) [Heartwood and sapwood](https://battleborntreeservice.com/glossary/heartwood-and-sapwood/) [CODIT (compartmentalization of decay in trees)](https://battleborntreeservice.com/glossary/codit/)

## Where this comes up

[Mower and string-trimmer damage: the quiet young-tree killer](https://battleborntreeservice.com/guides/mower-and-trimmer-damage-to-trees/) [Drought stress and dieback](https://battleborntreeservice.com/tree-guide/drought-stress-and-dieback/) [Callery (flowering) pear](https://battleborntreeservice.com/tree-guide/callery-flowering-pear/)