What wood moisture content will prevent fungus growth?

Fungal growth in wood occurs when the moisture content is at a level that supports microbial activity. Generally, wood that has a moisture content of 20% or higher is susceptible to fungus growth. Maintaining the moisture content of wood below 20% is crucial because once it rises above this threshold, the conditions become favorable for fungi to thrive.

This moisture level is a standard target in practices related to wood preservation and storage, as it ensures longevity and structural integrity. Therefore, the correct choice indicates a moisture content that effectively limits the possibility of fungus, making it an essential guideline for anyone working with wood in environments where it may be exposed to moisture.

Focusing on the other options: while a moisture content below 15% is ideal for preventing not only fungal issues but also other wood damage, the 20% threshold is the most appropriate standard to ensure prevention of initial fungal growth, which is why it is the correct answer in this context.