Using Tree Anatomy and Physiology for Identification

How a Tree's Parts Determing Tree Species Nomenclature

Douglas Fir Section On Display. Steve Brown/Flickr

Trees are among the earth's most useful and beautiful products of nature. Trees have been crucial to mankind's survival. The oxygen we breath is released by trees and other plants; trees prevent erosion; trees provide food, shelter, and material for animals and man.

Worldwide, the number of tree species may exceed 50,000. With this said, I would like to point you in a direction that will help you identify and name the 100 most common of 700 tree species that are native to North America. A bit ambitious, maybe, but this is one small step toward using the Internet to learn about trees and their names.

Oh, and you just might want to consider making a leaf collection as you study this identification guide. A leaf collection will become a permanent field guide to trees you have identified. Learn How To Make a Tree Leaf Collection and use it as your personal reference for future identifications.

What is a tree?

Let's start with the definition of a tree. A tree is a woody plant with a single erect perennial trunk at least 3 inches in diameter at breast height (DBH). Most trees have definitely formed crowns of foliage and attains heights in excess of 13 feet. In contrast, a shrub is a small, low growing woody plant with multiple stems. A vine is a woody plant that depends on an erect substrate to grow on.

Just knowing a plant is a tree, as opposed to a vine or a shrub, is the first step in it's identification.

Identification is really quite simple if you use these next three "helps":

  • Find out what your tree and its parts look like.
  • Find out if your tree will or won't grow in a particular region.

Tips: Collecting a branch and/or leaf and/or fruit will help you in the next discussions. If you are really industrious, you need to make a collection of wax paper leaf pressings.

Using Tree Parts and Natural Ranges for Species Identification

Help #1 - Find out what your tree and its parts look like.

Tree botanical parts like leaves, flowers, bark, twigs, shape, and fruit are all used to identify tree species. These "markers" are unique - and in combination - can make quick work of identifying a tree. Colors, textures, smells, and even taste will also help in finding the name of a particular tree. You will find reference to all of these identification markers in the links I have provided. You might also want to use my Tree ID Glossary for terms used to describe the markers.

Help #2 - Find out if your tree will or won't grow in a particular area.

Tree species are not distributed at random but are associated with unique habitats. This is another way to help you discern a tree's name. You can possibly (but not always) eliminate trees that don't normally live wild in the forest where your tree lives. There are unique timber types located throughout North America.

The northern coniferous forests of spruces and firs extend across Canada and into the northeastern United States and down the Appalachian Mountains. You will find unique hardwood species in the eastern deciduous forests , pine in the forests of the South, Tamarack in the bogs of Canada, the Jack pine in the Great Lakes region , the Doug Fir of the Pacific Northwest , the Ponderosa Pine forests of the southern Rockies.

Help #3 - Find a key.

Many sources of identification use a key. A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. Keys consist of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step.

Here is a great tree key you can use from Virginia Tech: A Twig Key - used during tree dormancy when leaves are not available...

Online Tree Identification

You now have real information to help identify and name nearly any tree in North America. The problem is finding a specific source describing a specific tree.

The good news is that I have found sites that help in identifying specific trees. Review these sites for more information on tree identification. If you have a particular tree that needs a name, start right here:

Top 100 North American Trees
A heavily linked guide to conifers and hardwoods.

VT Dendrology Home Page
Virginia Tech's excellent site.

Gymnosperm Database at
A great site on conifers by Christopher J. Earl.