Here are the web links—plus some new material—from the Next Steps section at the back of Stikky Trees

Now that you know the most common trees, there is much more you can explore. We’ve included enough here to keep you busy.

If you know of a resource you feel we should list here, please email it to : insider1 (at) stikky.com.

More trees

Stikky Trees introduced the 15 most common types of tree in the us as a whole (according to the us Forest Service database). But you’ll find it helpful to know which of these are common in your area. We’ve listed the top 10 for each state at www.stikky.com/trees (click on “Insider”).

An excellent way to practice identifying trees is to pick an area near where you live—a piece of woodland, a park, or a tree-lined street—and make it a project to name every tree there. It helps to have a pocket guide:

  • James Kavanagh’s Pocket Naturalist series is a fold-out card featuring over 100 trees and each card in the series shows the trees local for a single us state.

  • Northwoods (www.northwoodsguides.com) publish a set of cards small enough to carry anywhere (one inch by four inches) featuring 36 trees.

  • Fandex: Trees from Workman Publishing covers 50 trees with several pictures and quite a bit of information for each. The only downside is that you have to have a large pocket.

  • Nature Study Guild’s Tree Finder, Winter Tree Finder, Desert Tree Finder, etc, are mini books that are a little slower to use (you work through a series of questions) but more comprehensive.
You will quickly come across trees we have not covered. Here are some of the easier-to-identify ones that don’t make the top 15:

Beech, which has smooth, gray bark that looks a lot like elephant skin. Beech leaves are easily confused with tupelos.

Tamarack (aka Larch) is a less-common needle tree that has lots of needles sprouting from the same point on the twig (rather than just a few, like pines).

Flowering Dogwood, also has smooth-edged leaves but adds white or pink flowers in spring.

Willow, has long, thin leaves (drooping on Weeping Willows).

Cherry, some of whom must have missed the lecture on photosynthesis and so produce deep red leaves instead of green.

Sassafras, wins the prize for the craziest-looking leaf (some look like three-toed feet, others like mittens), used to make tea and root beer.

Ginkgo, runner-up in the crazy leaves contest (its are fan-shaped), used for a herbal remedy supposed to improve memory.

Palm trees are not, according to purists, true trees. Their trunks are not made of real wood, they don’t get thicker each year, and they don’t branch. They are, perhaps, just large plants.

While we are on the topic of what a tree is: anything shorter than 20 feet is usually considered a shrub though this is a little unfair since they work in the same way.


Advanced tree identification

Though we have been talking in terms of ‘pines’ and ‘oaks’ there are, of course, several different types of pine and oak: the ponderosa pine, for instance, or the white oak. Technically, ‘oak’ is the genus (pronounced “jen-us”) and ‘white oak’ is the species.

There are over 800 different species of tree in North America and 80,000 worldwide. Again, the best way to learn is to identify every tree in an area you know well. To identify species, you’ll need a full field guide (see the next section).

In case you are interested, the top 10 species in the US are (most common first):

  1. Red Maple (whose scientific name is Acer rubrum, Acer is ‘maple’ and rubrum is ‘red’)
  2. Loblolly Pine (Pinus taeda)
  3. Sweetgum (Liquidambar styraciflua)
  4. Douglas-fir (Pseudotsuga menziesii)
  5. Quaking Aspen (Populus tremuloides)
  6. Sugar Maple (Acer saccharum)
  7. Balsam Fir (Abies balsamea)
  8. Flowering Dogwood (Cornus florida)
  9. Lodgepole Pine (Pinus contorta)
  10. White Oak (Quercus alba)


Field guides

There are several comprehensive field guide books on the market, though all seem to be organized for experts, so that it will often take you several minutes to identify a tree:

Peterson’s Field Guide to Eastern Trees and Field Guide to Western Trees were created before printing color of every page was economically viable, so the color photographs are separated from the descriptions making the guide very difficult to use.

The Audubon Society’s Field Guides do the same thing, but make a better fist of the illustrations.

Smithsonian Handbooks: Trees has the distinct advantage of putting color photographs and text descriptions on the same page. But it doesn’t tell you much of interest about each tree and it insists on using the Latin names in the key at the front (you have to go to the index instead).

A Natural History of Eastern Trees and A Natural History of Western Trees, both by Donald Culross Peattie, are classics. They aren’t really identification guides (they have no color photos, for instance) but connect American history to each species in a unique and fascinating way. Highly recommended.

The definitive volume in trees is Michael Dirr’s 1200-page Manual of Woody Landscape Plants which has as much detail as you could want, and then some.

There are also several online guides including:

Eric Haines’ identification guide and tree quiz (www.realtimerendering.com/trees/trees.html)

The National Arbor Day Foundation’s What Tree is That? (www.arborday.org/trees/treeID.cfm)

and About.com (http://forestry.about.com/cs/treeid/a/tree_id_web.htm).

You may be able to find a tree identification site specific to your local area if you Google your state name and “tree identification”.

Michigan State University has a thorough example at http://forestry.msu.edu/uptreeid.


How trees work (in a nutshell)

  1. Trees make food by the magic of photosynthesis in their leaves. Photosynthesis takes carbon dioxide from the air and converts it to carbohydrate (ie, starch). To do this, leaves need sunlight. So the tree, the trunk, the branches, and all are basically a means to get as much sunlight as possible.

  2. But there’s a problem. Water evaporates through the same holes in the leaves that carbon dioxide comes in through. In fact, a large tree will lose 80 gallons of water a day! Where does all this water come from?

  3. The answer is: that’s the job of the tree’s roots. They suck water from the earth. They can usually find enough water near the surface, so roots spread out rather than digging deep into the ground as most people imagine.

  4. But the roots have to get the water up to the leaves. So the trunk contains a set of very small pipes that pump the water up. This works well, until air gets in the system which effectively puts a pipe out of action. Since the tree has no way to repair it, it has to make more pipes.

  5. So new pipes are made each year and the old pipes are drained and abandoned. This is how the trunk gets fatter: the new pipes are in the new ring added to the outside of the trunk (just underneath the bark, whose job is to protect the pipes) and the old pipes become the dead wood at the heart of the trunk.

  6. All this plumbing takes energy to build and maintain. Where does the energy come from? From the food that the leaves are manufacturing.

    There’s more to the story (as usual) and an excellent book that tells it is Peter Thomas’s Trees: Their Natural History.


The five biggest enemies of trees

Trees do not suffer from old age the way animals do. The main living part of a tree—the layer just underneath its bark—is regenerated each year and so is forever young. Instead, trees’ main enemies are these five: fire, wind, beavers, disease, and loggers.

With a little ingenuity, you can read the clues in a wooded landscape and figure out which of these five was most recently at work. When you combine this with knowledge about the age of the surviving trees, you can build quite a detailed picture of the history of the area. (This section is based on Tom Wessels superb book Reading the Forested Landscape.)

  1. Fire. Though younger trees die, older trees, with larger trunks, often survive fires. They may display large scars at the base where dead leaves burned. (Incidentally, the same scars appear if the tree has been hit by something such as an automobile.) If you can see old trees and young trees but little in between, the young trees may have grown since the last fire.

  2. Wind. When trees are blown over their roots pull up a mound of earth. Even years after the trunks have rotted away, the mounds will be visible, with a depression next to them where the tree stood.

  3. Beavers. Stumps left by beavers show evidence of gnawing. There will be a pond and possibly a dam nearby.

  4. Disease. If one species of tree has fallen and others survive, disease is the most likely culprit: beech bark scale disease, Dutch elm disease, white pine blister rust, gypsy moth (attacks oaks), and woolly adelgid (hemlock).

  5. Loggers. If logging killed the trees, the felled trunks will not be on view. The cut stumps may re-grow, giving rise to multi-trunked trees (though this could also indicate fire or beavers).

Trees are not defenseless to all of these enemies; they have evolved protection such as resin, gum, and latex, to heal over wounds and to keep enemies out. Notice that all of these have sealing properties that humans have found valuable too.

And, occasionally, a tree performs an amazing act of survival. A ginkgo tree that grew near the epicenter of the Hiroshima explosion survived and re-grew from its base.


Where new trees come from

If trees want to create offspring, they have to overcome one big problem: they can’t move. That means they have to come up with ingenious ways to (a) find a mate and (b) send their progeny off to new ground. Here’s how they do it:

  1. A tree’s equivalent of sperm is pollen. It is usually thrown into the wind in the hope it will land on the female part (the stigma) of a nearby tree of the same species. This is rather like trying to send a letter to a friend by making thousands of copies and throwing them from a tall building. Since this is a hit and miss affair, trees produce a lot of pollen. A single birch catkin can contain five million grains. (And so, for some humans, hay fever.)

  2. Some trees—the ones that flower in the spring such as flowering dogwood and cherry—make use of insects to spread their pollen instead of the wind. These trees need to attract the insects, who are suckers for bright petals, scent, and nectar, hence the flowers.

  3. In case pollen dispersal—by wind or animal carrier—fails, some trees can fall back on self-pollination as a last resort.

  4. Pollen is dispersed in spring and, if successful in arriving at a stigma, the result, sometime later, is a seed. The next problem is to get the seed to fertile new ground.

  5. Cone-bearing trees (pines, spruce, fir, etc) simply throw the seed into the wind, the same way they disperse pollen. Other trees wrap the seed up with some food, like a spaceship ready to colonize a new world.

  6. There is an enormous variety of these seed spaceships: acorns (from oak trees), nuts, fruit (eg, from apple trees), winged samaras (little helicopters, from maples for example), etc. Technically, all of these are fruit. They may be scattered by the wind, buried by squirrels, or eaten but not completely digested by birds.

  7. The vast majority of seeds perish. One oak acorn in a thousand becomes a seedling. And one seedling in a thousand ends the journey as a mature oak.


Visiting trees

Botanical gardens and arboreta present the ideal opportunity to practice and extend your tree identification skills. They have trees from all around the country (sometime all around the world) and they are, for the most part, labeled. A word of warning, though: if you simply read the labels, you won’t learn much. Instead, try to name the tree before looking at its label.

There are over 100 gardens and arboreta in the us. The American Association of Botanical Gardens and Arboreta has a searchable database of many—but not all—of them (www.aabga.org). Here are some of the larger ones:


Many university campuses have created online maps and walks of their trees and that access to them is free. Google your nearest.

If you’d rather sample a real forest, the US Forest Service has detailed information, visitor maps, and links for 150 of them at www.fs.fed.us. Alternatively, try a national park: the National Park Service is at www.nps.gov.

If all else fails, you can grow your own tree. Several online tree stores will help you figure out which trees are likely to grow well in your climate and soil—and then ship you a sapling (unless your state Department of Agriculture imposes restrictions, as do ak, az, ca, hi and others). Try www.arborday.org, www.naturehills.com, or www.historictrees.org (which, somewhat bizarrely, sells descendants of “famous” trees such as the Graceland sweetgum and Gettysburg address honeylocust).


Stikky recommended websites

There are hundreds of websites related to trees. Here are a few more of our favorites:

  • www.americanforests.com, a non-profit, includes the National Register of Big Trees, and American Forests magazine

  • http://tree.ltrr.arizona.edu, the Laboratory of Tree-Ring Research, will teach you to date the age of a tree by counting the number of rings in the trunk. Traditionally, this required having a cross section of the trunk (so the tree would have to be cut down). These days investigators use special tools to drill into the tree, producing a thin sample that does not harm the tree.

  • Both http://plants.usda.gov (the United States Department of Agriculture’s Plants Database) and www.hort.uconn.edu/plants (the University of Connecticut Plant Database) include photographs, scientific information, and distribution maps (showing where the tree grows) for just about every us tree.

  • www.wikipedia.com, an enormous, free, and surprisingly high quality encyclopedia has dozens of entries on trees.