Eve Lonnquist’s family has owned a forest in the mountains of northwest Oregon since her grandmother bought the land in 1919. Her 95-year-old father still lives on the 157-acre property. And she and her wife often drive up from their home just outside Portland. But lately, Ms. Lonnquist, 59 and recently retired, has been thinking about the future of her family’s land. Like many small-forest owners, they draw some income from logging and would like to keep doing so.