Oregon Public Broadcasting

Discussions continue later this month about management of Forest Park. April Baer reports scientific research casts doubt on the health of the park’s key resource: its trees.

Later this month, an advisory committee submits its recommendations for how cyclists use Forest Park.

That discussion may be informed by Nancy Broshot’s scientific study. She’s a biology professor at Linfield College.

Broshot has hiked through Forest Park observing saplings for seventeen years. Her view of the park splits into three sections: One is smack in the middle of the city, one is slightly farther out, and a third lies in less populated areas.

Nancy Broshot  “When I went out in '93, There were very few saplings and seedlings  in city section of the park, but when I got out in the middle and far sections of the park and up in the old growth, I had all kind of seedlings and saplings at my sides.”

At the time, she figured urbanization in the city-end of the park was taking its toll. But starting in 2003, she went back and did the same measurements again, with results Broshot  says she found astounding.

Nancy Broshot  “The first thing I noticed – they were gone.”

Sapling mortality for all three areas had gone up significantly – not just in the parts of the park near the city.

Broshot says she thinks there’s a connection between her results and the urbanization of the forest – more people living nearby, more impermeable surfaces, more invasive species.

But she says it’s much too early to limit park use – she’s not in favor of that.

Portland Parks officials are interested in Broshot’s data, with the understanding that it’s just one study.

Dan Moeller is the Natural Areas Supervisor for Portland Parks and Rec.

Dan Moeller “Nancy studied a number of sites in the park. I have no reason to interpret it one way or the other. Certainly it’s good information and  what it’s done for me is just indicate that more research needs to be done.”

Parks officials note Broshot gathered information at trailheads and perimeter edges. They say they’d like to see expanded studies in the park’s green interior.