Sunday, January 15, 2012

Native Evergreen Conifers in North Georgia

As a companion piece to my posts last year on Winter Twigs and Leaf Identification, this post gives some tips for learning how to identify some of the more common native evergreen conifers that grow in north Georgia.  As you may know, not all evergreens are conifers (think of hollies and rhododendrons), and not all conifers are evergreen (think of bald cypress). But since most conifers ARE evergreen, we've got a few things to work with here.

Blue-green foliage of white pine



Tsuga, hemlock










In the great kingdom of Plantae, conifers in Georgia are found in the Division Coniferophyta, in the Class Pinopsida, and in the Order Pinales, which has five families.  And within the Pinales Order, only two families are represented in Georgia: Cupressaceae and Pinaceae.  That is to say, there aren’t many conifer families in Georgia!  Of note: we are just outside the natural range of Abies (fir) and Thuja (arborvitae).




Tsuga canadensis foliage
The Pinaceae family is where most of Georgia’s evergreen conifers reside yet it is represented by just 2 out of the nine genera here: Pinus and TsugaTsuga, known as hemlock, has two species: Tsuga canadensis is more prevalent than Tsuga caroliniana.  Hemlock is very shade tolerant and is generally found in mountain communities, but it does fairly well in gardens as well.

Hemlock is easily noted by its flattened, short needles; it's graceful, drooping form; and by the tiny, flexible cones it produces. The needles are single and are two-ranked along the stem, meaning they reside in a horizontal plane.



Pines have round needles that surround the stem (not two-ranked), often lose their lower branches over time, and have stiff cones that sometimes have prickles.  The needles are arranged in bundles along the stem.

With the common pines of north Georgia I find that looking at the needles is the quickest way to make an identification.  If you were to look at a list of the pines (Pinus spp.) that are native to Georgia, this might seem a little daunting. But if you live in north Georgia like I do, there are really only four and, with just a little help, I think you can learn to tell them apart.  If you live elsewhere, perhaps you can pick some tips on how to identify them in general.

The four pines that you are likely to find in north Georgia are: Pinus echinata (shortleaf pine), Pinus strobus (eastern white pine), Pinus taeda (loblolly pine), and Pinus virginiana (Virginia pine).  The needles are arranged in bundles within a fascicle at the base of a bundle, so you need to examine how many there are, how long they are, and if they are straight or twisted.

From top to bottom, the picture above shows:

loblolly (usually 3 needles per bundle, length is 5-8 inches); 
eastern white pine (5 needles per bundle, color is bluish-green); 
shortleaf pine (2-3 needles per bundle, length is 3-4 inches); 
Virginia pine (2 needles per bundle, needles are short and twisted).



Below are some pictures of the cones:
Pinus taeda: large cones with prickles

Pinus strobus: long cones, no prickles

Pinus echinata, short cones stay on
tree; small prickle

Pinus virginiana, short cones stay on
tree but prickle is long and sharp























White pine branches




White pine does have one interesting growth characteristic - the branches tend to encircle the tree, like spokes on a wheel. So, if the branches are intact, you might be able to confirm it by looking at the trunk.

By the way, pines do lose their leaves (that is, their needles), just not all at once.  The loblolly pines in my yard drop some needles in the fall, about the same time that deciduous trees are dropping theirs too.






The Cupressaceae family is represented by 3 genera in Georgia: Chamaecyparis, Juniperus, and TaxodiumTaxodium, a genus perhaps most familiar to people by the species Taxodium distichum (bald cypress), will not be covered here because it is deciduous (a trivia question for your family: "Name a deciduous conifer"). Chamaecyparis is represented in Georgia by Chamaecyparis thyoides (Atlantic white cedar) but that is not indigenous to north Georgia (although people do grow it here). That leaves us with Juniperus virginiana which is found throughout Georgia; however, it is best known by its common name, eastern redcedar.  People are often surprised when you tell them it is a juniper.

I learned something when I was researching Juniperus virginiana for this article.  I was certainly familiar with the plant - it grows everywhere around here, and I've dug up many a small one. However, I had not seen one with fruit so I decided to try and find one.  I looked at a lot of trees before I found one, but I was puzzled when I did.  The foliage didn't look right.  As I dug into my references a little deeper, I found the answer.  The mature foliage is different!  Juvenile foliage is needle-like and prickly - what I was used to seeing; the mature foliage is "awl-like" and scaly with overlapping sections - not prickly.

Berries and mature foliage, Juniperus virginiana
Juvenile foliage, Juniperus virginiana


It is also curious to think that junipers have berries - why would a conifer have berries instead of cones?  Well, the "berries" are actually cones with fleshy scales that have fused together, creating the appearance of a berry.









So now that you know a little bit more about identifying these plants, spend some time outside practicing your identification skills.  Those fragrant green trees with needles are not all alike; the differences are there for you to discover.





Good tree identification references for the southeastern U.S.:

Native Trees of the Southeast: An Identification Guide by Kirkman, Brown and Leopold
Woody Plants of the Southeastern United States by Ron Lance
Guide to Southern Trees by Harrar and Harrar (Dover publication) – you can get this used on Amazon for as little as $1.50 plus shipping; it’s a great starter for young people and the line drawings are excellent.

2 comments:

  1. Thanks for this, I often have trouble with distinguishing between Virginia Pine and Short-Leaf Pine. (I hate calling it Short-Leaf, I want to call it Short-Needle)

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  2. I asked my family your trivia question: "Name a deciduous conifer". They said Larry if it's a boy and Susan if it's a girl.

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