For all future stewards of the earth -- and that's all of us -- here's a quick quiz. What is the most renewable and sustainable material with which to build our homes? How can we turn some of the CO2 we're putting into the atmosphere into an asset? And how can we make the world more beautiful and green?

The answer to all these questions is... trees. 

Trees make up about 90 percent of all the living biomass on Earth. And forests serve as home to the majority of species on the planet. We use thousands of products -- many every day -- that come from trees. Some are obvious like wood and paper and many not so obvious like microcrystalline cellulose, a key ingredient in many medicines.

Anyway, who doesn't love trees? 

Yet trees, especially in the last few decades, have become very controversial. People are divided into two broad camps. One group sees trees as a critical source of renewable material and of renewable energy. This group generally favors planting trees and making use of the many products derived from them. The other group emphasizes the value of forests as ecosystems to provide a protected habitat for threatened species. This group prefers to see forests off-limits to commercial use. 

The arguments between these two groups can get pretty heated. But here's the good news: if we do it right, we can use our trees and enjoy them, too. Before I explain how, I need to define two terms: The first is "forestry," which means the creation, management, and use of forests. The second term is "deforestation," which means the permanent loss of forests. 

There are two widespread misconceptions about forestry. The first misconception is that forestry, as practiced by the forest industry, is responsible for deforestation. We may think that when we buy wood from a lumberyard we are causing a bit of forest to be lost somewhere. But what we are really doing is sending a signal to the marketplace to plant more trees to produce more wood to supply the demand in the lumberyard. It is no different from any other renewable crop. It's just that trees take longer to mature than annual farm crops. The giant paper company Boise Cascade is just as much in the business of planting trees as it is in harvesting them. 

The key point is it's not the harvesting of trees that causes deforestation. Deforestation is the result of harvesting and then not replanting a forest, or not letting it grow back naturally, which it would do if just left alone. 

Deforestation sounds like a bad word -- and it can be -- but usually it's not. All it means is that after the trees are harvested, the land is used for a different purpose. The largest cause of deforestation is agriculture, the creation of new farmland.  But farming is important. After all, the world has seven billion people to feed. Another reason for deforestation is to make way for towns and cities. Manhattan was once a great forest. Now it's a great city. 

The second misconception about forestry is the tendency to judge landscapes by how they look to our eyes. We easily make the mistake of using our sense of what is beautiful and what is unsightly to judge the ecology of the land. This results in repulsion at the sight of a recently logged landscape because it looks ravaged, destroyed, and unsightly. We don't react this way to a landscape of pasture with sheep peacefully grazing or a wheat-field waving in the wind. Yet both are examples of deforestation.  Where there once was a biodiverse natural forest we now have a ranch or a farm. In other words, we judge the book by the cover and equate beauty with ecological health and unsightliness with destruction of nature.

These impressions have led many environmentalists to support cutting fewer trees, as if our forests are disappearing. But they're not. There is the same area of forest in the U.S. and Canada today as there was 100 years ago. If anything, it's growing. This despite the fact that the population has tripled. But the professional environmentalists are never satisfied. They behave as if every tree should be protected and that the products they yield are unnecessary.

This is badly misguided. The correct position, from a purely environmental perspective, is to grow more trees, the world's most abundant renewable resource, and use more wood. We can do both. In the end, we're all tree huggers. 

I'm Patrick Moore, co-founder of Greenpeace, for Prager University.