There are more trees now, but they're young, so protection of old-growth forests is key. (Photo: Tatiana Marcinkowski/Shutterstock)

The numbers are in.

In the United States, which contains 8 percent of the world's forests, there are more trees than there were 100 years ago. According to the Food and Agriculture Organization (FAO), "Forest growth nationally has exceeded harvest since the 1940s. By 1997, forest growth exceeded harvest by 42 percent and the volume of forest growth was 380 percent greater than it had been in 1920." The greatest gains have been seen on the East Coast (with average volumes of wood per acre almost doubling since the '50s) which was the area most heavily logged by European settlers beginning in the 1600s, soon after their arrival.

This is great news for those who care about the environment because trees store CO2, produce oxygen — which is necessary for all life on Earth — remove toxins from the air, and create habitat for animals, insects and more basic forms of life. Well-managed forest plantations like those overseen by the Forest Stewardship Council also furnish us with wood, a renewable material that can be used for building, furniture, paper products and more, and all of which are biodegradable at the end of their lifecycle.

The increase in trees is due to a number of factors, including conservation and preservation of national parks, responsible tree growing within plantations — which have been planting more trees than they harvest — and the movement of the majority of the population from rural areas to more densely populated areas, such as cities and suburbs. Tree planting efforts that started in the 1950s are paying off, and there is more public awareness about the importance of trees and forests. Finally, 63 percent of the forest land in the United States is privately owned, and many landowners are leaving their land intact instead of using it for agriculture or logging (at least partially because many of these activities have shifted overseas).

The average age of forests in the United States is younger than it was before European settlement. The greatest diversity is found in the oldest forests, so there may be more forest now, but because it is so young, it is home for fewer animals, plants, insects and other organisms than a fully developed, mature forest ecosystem. It also means that protecting old growth forests is imperative.

As a society, we are likely in the middle of our cultural (and scientific understanding) of the value of forests. The history of conservation in this country is still young, after all. According to Chuck Leavell, director of Environmental Affairs at MNN and a tree farmer, "It was during the Theodore Roosevelt administration that conservation began to take hold, and along with Roosevelt, figures like Gifford Pinchot, John Muir and others began to warn Americans about overuse of our natural resources. Eventually, programs were put into place that encouraged landowners to plant trees ... in some cases encouraging farmers to convert some of their farm lands into forests."

We can't go back and reverse what we've done to the forests, but we can support current conservation efforts. While our forests are recovering, their protection will only encourage what Leavell calls, " ... a remarkable restoration of American forests."

Spotted owls are key indicators of the health of old-growth forests in Oregon. (Photo: Oregon Fish & Wildlife)

One of the main reasons forests are recovering is the role of government, which now agrees that responsible management practices are important for future forest ecosystem health. In 1992, the United Nations adopted the "Forest Principles" which kicked off the latest round of modern sustainable forest management initiatives in the U.S. and abroad.

The definition of sustainable forest management, as understood by the FAO is: The stewardship and use of forests and forest lands in a way, and at a rate, that maintains their biodiversity, productivity, regeneration capacity, vitality and their potential to fulfill, now and in the future, relevant ecological, economic and social functions, at local, national, and global levels, and that does not cause damage to other ecosystems. These rules now govern how forests are managed.

Trees do more than protect water resources and produce oxygen, they are also good carbon sinks, which is more and more important in a warming world (carbon dioxide is one of the main global warming gases). As they grow, trees use and store CO2, making them popular bulwarks against climate change. In fact, quite a few carbon offsetting companies include tree planting as part of their portfolio.

Basically, the more trees, the more oxygen, and less carbon dioxide, (though there may be exceptions to this rule in northern latitudes, according to climate models). "At present, the U.S. does not have any type of carbon tax or cap-and-trade system," says Leavell. "Europe does, with mixed reviews and mixed success. But there is not a doubt that the forests of the world sequester more carbon than anything else."

Leavell points out that many of America's national parks were originally set aside as a "wood resource" though they are largely unlogged today, though there are still some controversial moves in old-growth areas. Only about 7 percent of U.S. forests are part of national or state parks, but many of those now encompass what we consider to be "environmentally sensitive" areas, or unique ecosystems. (Think California's redwoods or small patches of old growth forests on the East Coast.)

Moving forward, we will continue to have more trees, and more forests than in years past. It's important that we encourage foresters and governments in Third World countries, where deforestation is still occurring at an alarming rate, to do the same.

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.