How can you determine if bark fungus has penetrated living tissue?

To determine if bark fungus has penetrated living tissue effectively, scraping the bark to reach the cambium layer is crucial. The cambium is a thin layer of living tissue located just beneath the bark, responsible for the growth of new wood and phloem. When you scrape away the outer bark, you can assess the condition of the cambium and determine if it's healthy or compromised by pathogens such as fungi.

If the cambium is discolored, mushy, or shows signs of decay, it indicates that the fungus has successfully invaded and is affecting the living tissues. This hands-on approach provides direct evidence of tissue integrity, which is vital when assessing tree health and making management decisions.

Visual inspection alone does not provide sufficient information about the health of the underlying living tissues, as external indicators may not reveal internal damage caused by fungal invasion. Monitoring growth patterns can offer some insight into a tree's health over time but lacks the immediacy and accuracy of directly inspecting the cambium layer. Measuring soil moisture levels is related to overall tree health but does not specifically indicate the presence of bark fungi or their effect on living tissues. Thus, scraping to the cambium provides the clearest and most direct evidence of fungus penetration.