---
title: CODIT: How a Tree Seals Off Decay
url: https://battleborntreeservice.com/glossary/codit/
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)
---

- [Home](https://battleborntreeservice.com/)
- [Arborist glossary](https://battleborntreeservice.com/glossary/)
- CODIT (compartmentalization of decay in trees)

# What is CODIT?

CODIT stands for compartmentalization of decay in trees. It is a model, developed by tree biologist Alex Shigo, of how a tree walls off damaged and decayed wood so that the rot stays in one place and the tree keeps growing.

## How the model works

A tree does not heal an injury the way a person does. It surrounds the injured wood with chemical and physical barriers and grows new wood outside them. The model describes four walls: one stops decay moving up and down, one stops it moving inward toward the center, one stops it moving sideways around the trunk, and one, the strongest, is the barrier zone formed by the cambium after the wound. The three inner walls are weak points, and the fourth is the line the tree builds.

The practical point is that a tree's response is limited. A big wound, or many wounds in one place, can overwhelm it. See [woundwood](https://battleborntreeservice.com/glossary/woundwood/).

## Why it matters in Northern Nevada

Trees here make their walls on little water, and species differ. Species differ in how well they compartmentalize, and a stressed tree does it less well. That is one reason a tree that lost a limb to a snow storm and a flush cut can decay years later, and why old trees seem fine until a limb drops. It also explains why a hollow tree can stand: the wall around the decay may be sound. See [cavity](https://battleborntreeservice.com/glossary/cavity/).

This is a general model and individual trees vary, which is why an assessment looks at the tree in front of you.

## What an arborist does about it

CODIT is behind the standard advice: make small, correct cuts at the [branch collar](https://battleborntreeservice.com/glossary/branch-collar/), avoid unneeded wounds, never use a flush cut, and avoid cutting more than a tree can seal. It is also behind the recommendation against filling cavities and against painting cuts. The arborist reads old wounds to see whether the tree is coping, and recommends monitoring, support or removal on that basis.

### Sources

- [International Society of Arboriculture, Trees Are Good: Why Topping Hurts Trees (brochure)](https://www.treesaregood.org/Portals/0/TreesAreGood_Why%20Topping%20Hurts_0321.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/)
- [Root and trunk decay](https://battleborntreeservice.com/tree-guide/root-and-trunk-decay/)
- [Dead wooding explained](https://battleborntreeservice.com/guides/dead-wooding-explained/)
- [Arborist consultation](https://battleborntreeservice.com/tree-services/arborist-consultation/)

## See also

[Woundwood](https://battleborntreeservice.com/glossary/woundwood/) [Cambium](https://battleborntreeservice.com/glossary/cambium/) [Cavity](https://battleborntreeservice.com/glossary/cavity/) [Branch collar](https://battleborntreeservice.com/glossary/branch-collar/)

## Read it in context

[Should pruning cuts be sealed or painted?](https://battleborntreeservice.com/faq/pruning-and-trimming/should-pruning-cuts-be-sealed/)