Slide 14 of 31
Chip mill distance is statistically and positively related to the age of stands, other variables held constant. Because chip mills often have only been on the land for a few years, their existence post-dates the FIA survey whose stand age is being modeled, because they are somewhat mobile, and because they are often quite small, these findings are somewhat surprising. What this relationship is probably revealing is one of or a combination of two causes: chip mills are sited so that they are close to young stands. Another explanation is that chip mill locations are close to where remote log concentration yards located; chip mills replaced many of these, which were causally linked to stand age.