Here are the
web linksplus some new materialfrom 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.
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:
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:
- 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
- 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.
which has smooth, gray bark that looks a lot like elephant skin. Beech leaves
are easily confused with tupelos.
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).
some of whom must have missed the lecture on photosynthesis and so produce
deep red leaves instead of green.
the prize for the craziest-looking leaf (some look like three-toed feet,
others like mittens), used to make tea and root beer.
runner-up in the crazy leaves contest (its are fan-shaped), used for a herbal
remedy supposed to improve memory.
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
- Red Maple (whose scientific name is Acer rubrum,
Acer is ‘maple’ and rubrum is ‘red’)
- Loblolly Pine (Pinus taeda)
- Sweetgum (Liquidambar styraciflua)
- Douglas-fir (Pseudotsuga menziesii)
- Quaking Aspen (Populus tremuloides)
- Sugar Maple (Acer saccharum)
- Balsam Fir (Abies balsamea)
- Flowering Dogwood (Cornus florida)
- Lodgepole Pine (Pinus contorta)
- White Oak (Quercus alba)
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
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
The National Arbor Day Foundation’s What Tree is That?
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)
- 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.
- 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
- 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.
- 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
- 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.
- 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.)
- 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.
- 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
- Beavers. Stumps left by beavers show evidence of
gnawing. There will be a pond and possibly a dam nearby.
- 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).
- 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
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:
- 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.)
- 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.
- In case pollen dispersal—by wind or animal carrier—fails,
some trees can fall back on self-pollination as a last resort.
- 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.
- 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.
- 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.
- 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
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:
- Arnold Arboretum of Harvard
University, Jamaica Plain, MA, www.arboretum.harvard.edu
- Brooklyn Botanic Garden, Brooklyn, NY, www.bbg.org
- Cornell Plantations, Ithaca, NY, www.plantations.cornell.edu
- Dawes Arboretum, Newark, OH, www.dawesarb.org
- Denver Botanic Garden, www.botanicgardens.org
- Garvan Woodland Gardens, Hot Springs, AR, www.garvangardens.org
- Holden Arboretum, Kirtland, OH, www.holdenarb.org
- Minnesota Landscape Arboretum, www.arboretum.umn.edu
- Morris Arboretum, Philadelphia, PA, www.business-services.upenn.edu/arboretum/
- Morton Arboretum, Lisle, IL, www.mortonarb.org
- Muir Woods National Monument, Mill Valley, CA, www.visitmuirwoods.com
- New York Botanical Garden, Bronx, NY, www.nybg.org
- North Carolina Arboretum, Asheville, NC, www.ncarboretum.org
- Red Butte Garden, Salt Lake City, UT, www.redbuttegarden.org
- San Francisco Botanical Garden, www.strybing.org
- The Arboretum at Flagstaff, AZ, www.thearb.org
- United States Botanical Garden, Washington D.C.,
- United States National Arboretum, Washington D.C.,
- University of California Botanical Garden, Berkeley,
- Washington Park Arboretum, Seattle, WA, http://depts.washington.edu/wpa
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).
(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
a non-profit, includes the National Register of Big Trees, and American
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
- Both http://plants.usda.gov
(the United States Department of Agriculture’s Plants Database)
(the University of Connecticut Plant Database) include photographs,
scientific information, and distribution maps (showing where the tree
grows) for just about every us tree.
an enormous, free, and surprisingly high quality encyclopedia has dozens
of entries on trees.