This article is about hype in the sense of overstating positive effects by ignoring contradictory evidence. It relies on a two-pronged approach to demonstrate that popular and widespread claims about common mycorrhizal networks (CMNs) in forests are not well supported. CMNs can be roughly defined as a below-ground network of fungi that connect roots of multiple plants, including trees. First, the authors review the literature and examine 3 main claims: (1) CMNs are widespread in forests; (2) resources are transferred through CMNs, resulting in increased tree seedling performance; and (3) mature trees can warn each other of threats via CMNs.

The authors discovered that there was limited support for these claims. This was due to a combination of factors such as insufficient information, wide variations in results from different field studies, overlooked possible alternative explanations, and an overgeneralization of results. Then they manually examine whether citations received by 18 influential field studies were supported (i.e., with strong evidence for the claim) or unsupported (i.e., weak or not evidence to support the claim, or possible consistent alternative explanations). The analysis revealed that results were frequently misinterpreted and poorly communicated, with a significant bias towards studies that reported a positive effect of CMNs.

Their conclusion is that scientists may inadvertently propagate unsubstantiated claims and contribute to an inaccurate public narrative on the topic. They strongly urge the scientific community to conduct more rigorous studies and interpretations to prevent the concept of CMNs, also known as the wood-wide web, from becoming a mere fantasy.