Spring Has Sprung: Tree Terminology for Arbor Day: April 28

Arboreus is Latin for "tree." You'll see this in other tree-related words like arbor, a trellis used for training climbing plants, arboretum, a botanical garden focused on trees, and Arbor Day, a holiday that encourages people to plant trees.

Bough is another word for branch, below, though it usually refers to bigger ones connected directly to the trunk.

In Greek, konos means both the geometric solid and the seed-bearing parts of conifers, below.

You can see cone in conifer, which makes sense since coniferous trees like pines grow their seeds inside cones. They also don't drop their needles in the winter, and tend to have much softer, more bendable wood than deciduous trees. That's because keeping their needles means that their branches need to bend under the weight of heavy snow.

A Middle English word, copse refers to a thickly grown area of forest that is more easily walked around than through.

Unlike conifers, above, deciduous trees drop their leaves in the fall. Also generically known as "hardwoods," deciduous species include species like oak and maple. deciduus is a Latin word meaning "hanging down" or "falling."

A gall is a lump on the side of a tree trunk or branch caused by an insect laying its eggs inside the bark. The galls from oak trees, because of their dark discoloration, have been used to make ink and dye for centuries.

Phlóos is Greek for "tree bark," and the phloem form part of a tree's circulatory system, which is located just beneath its bark. If phloem sounds like "flow," that's not a coincidence; fluum, the Latin word that "flow" comes from, shares an Indo-European root with it.

Photo is Greek for "light," and synthesis means "composition." Trees use energy from sunlight plus carbon dioxide from the atmosphere to create carbohydrates that fuel their cells. As a byproduct of this reaction, they give off oxygen. This is why deforestation is accelerating climate change: trees remove greenhouse gases from the atmosphere.

Sap is the liquid that flows up from the roots to provide water and nutrients to a tree. The sap from maple trees is probably the most famous kind, because when it's boiled down it becomes maple syrup. Sweet! Sap as a verb means "to weaken," the way draining too much sap from a tree would cause its leaves to droop.

An Old English word with Germanic origins, timber refers to wood used for construction. Most famously, it's sometimes shouted by lumberjacks to warn others that a tree is about to fall.

Zylom means "wood" in Greek. Xylem, along with phloem comprise the circulatory system of trees, bringing water and nutrients up from the roots and sugars from photosynthesis in the leaves to all the cells of the tree.