What are some threats to North America's forests?

The threats to North America's forests include logging, non-native species, and wildfires. Logging poses a significant risk as it involves cutting down trees for timber, which can lead to habitat loss, soil erosion, and disruption of local ecosystems. Non-native species can further threaten forests by outcompeting native plants and altering the local ecological balance, which can lead to decreased biodiversity. Wildfires, while a natural part of many forest ecosystems, can become destructive, particularly when exacerbated by climate change and human activities, leading to large-scale forest destruction.

In contrast, the other choices include elements that are either less relevant to the threat posed to forests or do not typically have a direct negative impact on forest health. For example, tourism can have both positive and negative impacts but is generally not considered a primary threat compared to logging or invasive species. The reference to organic farming and fishing in some options indicates practices that, while they can affect environments, do not directly constitute significant threats to the integrity of forest ecosystems.