Can You Get More Than 11 Right on This Tree Knowledge Quiz?

Trees aren't annuals, they're perennials. That means they'll keep coming back, season after season, until they've reached the end of their lifespans.

All trees are woody creatures. The qualities of that wood varies greatly by species, location and health.

To be sure, there are plenty of shorter trees in the world. But most trees grow to a height of at least 20 feet, and often much, much taller.

Some trees have rough bark, others have smooth, skin-like bark. But all bark is the same in that it's meant to offer protection from the environment.

In Utah, there is a colony of aspens called Pando, the Trembling Giant. The colony has about 47,000 trees (more than 6,600 tons) regarded as one organism ... perhaps the second-largest organism on the planet (after a huge Oregon fungal colony).

Trees generally have long branches that reach to the skies. These branches terminate in a leafy crown that makes trees so distinctive.

Each year, deciduous trees lose their leaves at the end of the growing season. Then, the following year, those leaves begin growing back, starting with buds.

In California's White mountains you'll find Methuselah, perhaps the world's oldest tree. Scientists estimate this tree is around 4,700 years old.

Methuselah, a tree in California, is a bristlecone pine that's more than 4,700 years old. The tree's location is kept secret to prevent attention-seeking vandals from destroying it.

Evergreens are also conifers because they produce cones. Cones fall to the ground and scatter the plant's seeds, ensuring future generations.

Every year, trees typically grow a bit in the wet season, and then cell production slows during dry or cold periods. The growth rings of these cells are useful in determining the tree's age.

In the Giant Forest of Sequoia National Park of California, you'll find the General Sherman tree, a huge giant sequoia. From base to tippy top, the tree is nearly 275 feet tall. It is -- by mass -- the world's biggest tree.

Trees are incredibly useful to humans. Not only do they provide precious shade, but they filter our air, provide certain types of medicine, and much more.

Unlike most creatures, trees don't die of old age. They succumb to many other threats, though, from diseases to environmental changes and more.

Trees grow in almost all of Earth's climates and regions, from deserts to mountaintops. There are about 60,000 different species.

Tree bark is vital to the plant's health, offering protection from all manner of hazards. The bark is made up of dead cells that have desiccated on the plant's exterior.

Trees have all sorts of defense mechanisms. Volatile phenolic compounds are one way the plants ward off pests -- the chemicals may call in predators that keep invaders at bay.

At the tree trunk's core is the heartwood. The heartwood is typically darker in color than the rest of the truck, and it's important in providing stiffness to the trunk.

Some types of trees, like pines and firs, are known as evergreens. Their iconic green needles remain on the tree's branches for years, unlike deciduous leaves, which are shed annually.

In California, there exists a tree named Hyperion, a 380-foot tall redwood. Like other prized trees, the location of this one is secret so that no one will be tempted to damage it.

Pine trees are robust creatures capable of withstanding many environments. The only continent where they're not found is Antarctica.

As homeowners know, large oaks can generate copious numbers of acorns. A big tree might hurl 10,000 -- or more -- acorns in one season.

The next time you see a pine tree, you can start guessing -- is it dropping boy or girl cones? All cones carry just one sex in hopes of reproducing the species.

In Mexico you'll find the Arbol del Tule, a Montezuma cypress. This enormous tree is more than 38 feet in diameter ... perhaps making your first aparment look small by comparison.

In forests, not all trees are the same. Central "mother" trees often use fungal networks in the soil to send excess nutrients to smaller trees ... thereby strengthening the forest as a whole.

Trees are common, but species aren't always widespread. In fact, a little more than half of all known tree species grow in a single country, demonstrating how important it is for each nation to conserve its resources.

Plants need water, and that water must move somehow. Xylem cells have particularly thick walls that make them appropriate for their purpose -- water transportation.

Trees require a lot of water; the bigger the tree, the more water it needs. A huge oak might chug 100 gallons of water in a single day.

Trees are new kids on the block. Earth is about 4.5 billion years old. Trees didn't appear until about 400 million years ago.

The Earth has far fewer trees than it did before humans began cultivating crops. Agriculture and its associated land usage has cut tree numbers by about half since 12,000 years ago.

Many trees put down deep roots. But in most cases, tree roots are found no more than 18 inches deep.

The Amazon rainforest is vital to oxygen production on Earth. Each year, this 2.1 million square mile area generates about 20 percent of the planet's oxygen.

In tropical and subtropical regions, it's not seasons that trigger leaves to fall. Instead, it's rainfall (or lack thereof) that starts this process each year.

You'll have to forgive the white birch for the messes it makes. It leaves ragged horizontal strips of bark as it move through its life cycle.

In a discovery that still floors researchers, in 1994, the Wollemia (a cone-bearing evergreen) was found living in Australia. The catch? Scientists were sure it had gone extinct 150 million years earlier.