"Pennsylvania has some of the most productive forests in the world, but we can't get them to regenerate," Dr. Alt added.

The national parks in Norway are mostly located in mountain areas; about 2% of the productive forests in the country are protected.

The most productive forest is located in the central and eastern portions of the state.

An even larger percentage of the productive forest has been logged.

Much of the land is rock, ice, muskeg, or less productive forest on steep slopes.

The ashy soil holds moisture during the dry season and supports a productive spruce-fir forest.

The municipality has few productive forests, but there are some spruce trees planted in sheltered areas.

Stewardship plans also motivate landowners to become actively involved in planning and managing their land which eventually can lead healthier and more productive forests.

Studies have suggested that it is a more productive forest now.

Commercially productive forest stands at about 108,225 hectares with about sixty percent of the trees able to be sold.