First of all, I don't know exactly how it was introduced. I know we've done a lot of research, and have brought about a stronger white pine that can be resistant to blister rust. I can't tell you exactly how it was introduced. I can say that there are a number of tree diseases or pests that are brought in unintentionally, often with imports of trees or pallets.
The pallet industry is a major way that nematodes or fungi can come in. So you're seeing on the forest industry side—and I just know that because I have another life in the forestry world—there are way more protocols about what's required from the phytosanitary rules about how to bring in products that have wood wrappings or wood pallets in order to avoid that. So that's the unintentional side of invasive species, but the majority do come in intentionally, not unintentionally.