The Fruiting Habits of Junipers

Tiger and I were wandering around out at Jackrabbit Mountain earlier in the week, and we noticed that many of the juniper trees (Juniperus osteosperma) were packed with cones. The trees were so loaded with fruit that they appeared white (not that you can tell from this picture). In any case, we got to wondering about whether this kind of cone crop was a normal yearly occurrence. Because not every tree was covered with cones, I first wondered if Utah juniper trees were dioecious. (I can't pronounce that, but it means, essentially, that there are female trees and male trees.) Nope. According to the entry on Wikipedia, the Utah juniper is largely monoecious, with both sexes on one tree. So, then I wondered about the tree's periodicity. (I can't pronounce that either, but it simply refers to the typical time period between good cone crops.) I couldn't find any information about the periodicity of the Utah juniper, so I looked up two closely related trees. The western juniper (Juniperus occidentalis) produces good seed crops nearly every year, while the Rocky Mountain juniper (Juniperus scopulorum) produces heavy seed crops every two to five years. Assuming a similar cone production habit for Utah juniper, we shouldn't have been surprised by the good crop, it probably happens every year or two.