By the end of this month, about 3,110 acres of private forestland outside Northwest Portland will become part of Oregon State University’s new research forest. OSU announced Friday that it’s finalizing its purchase of land northwest of Portland’s Forest Park for $27 million, all of it covered by federal and regional grants. This area, which OSU calls the Tualatin Mountain Forest, had been managed as a timber plantation by forest products giant Weyerhaeuser Company. As such, most of the trees are no older than 35 years. OSU leaders say this landscape will become more ecologically diverse under the university’s ownership. The plan is to research what effects different types of logging practices have on tree diseases, pests and fire resilience. …This land acquisition comes a year and a half after OSU suddenly backed away from yearslong plans to manage the Elliott State Forest near the Oregon Coast as a research forest.