Certified Arborist Test 2025 – 400 Free Practice Questions to Pass the Exam

Wall 4 is recognized as the strongest in the CODIT (Compartmentalization of Decay in Trees) model, which describes how trees respond to injury and decay. This wall forms in response to an injury and is composed of both the xylem and a significant amount of lignin, which imparts strength and resistance to pathogen invasion.

The strength of Wall 4 is critical because it serves as the primary barrier against the advancement of decay, effectively compartmentalizing the affected area from the healthy tissue. Its robust structure allows it to limit the spread of decay within the tree, ensuring that the tree can continue to thrive despite localized damage.

Understanding the function and strength of Wall 4 is vital for arborists, as it informs them about tree health and the effectiveness of management practices when dealing with tree injuries or diseases. Proper identification of the strength of each wall in CODIT helps in making informed decisions regarding maintenance and care of trees.