Ace the Certified Arborist Test 2026 – Branch Out and Leaf Your Mark!

In the CODIT (Compartmentalization Of Decay In Trees) model, Wall 4 plays a crucial role in inhibiting the lateral spread of decay. This wall is formed by the tree's reaction to injury or infection, involving the development of specialized tissues that restrict decay from moving sideways into adjacent healthy wood.

Wall 4 is created by the accumulation of tyloses, resin, and other compounds in the xylem, contributing to the formation of barrier zones. These barriers effectively limit the spread of decay organisms by stopping them from traveling beyond the point of infection. By preserving the integrity of healthy tissues, Wall 4 helps the tree maintain its overall health and structure despite the presence of decay.

The function of the other walls in the CODIT model is different. While each wall contributes to the tree's ability to compartmentalize and manage decay, only Wall 4 specifically focuses on minimizing lateral spread. Understanding Wall 4's role is essential for properly assessing tree health and effectively managing diseases or wounds in arboriculture.