By Michael “House” Tain
More than a few arborists have been frustrated or amused by the tree identification skills, or lack thereof, of some of their customers, or even fellow tree care professionals. After all, spending the time and energy to do a free bid on a homeowner-described big pine that just died and lost all its needles, only to realize it’s a larch, which loses its needles every fall, can be a little trying. And let’s not forget that classic line of many a “tree cutter,” the always popular, “Well I don’t know what she is, but I’ll get her down for you.”
Knowing what type of tree is being dealt with is obviously important to be considered a tree care professional. After all, vital information such as probable diseases/pests, strength of wood, lifespan, decay resistance, etc. is all learned from identifying the tree in question. But the opportunity to educate the customer about their tree or trees is also important; and what better way to appear knowledgeable and professional than to readily identify the tree and its habits. This doesn’t mean that an arborist must know every species of tree in existence. Much as a lawyer might need to refer to case law or a doctor run additional tests, an arborist cannot be expected to immediately identify every individual within the wide variety of cultivars, exotics and ornamentals existing in the landscape. But some level of basic knowledge of tree identification should be part and parcel of every tree crew member’s skill set. It’s not going to do any good for the foreman to send Johnny B. O’Doughnuts to the backyard to deadwood the maple, only to discover later that Johnny just spent three hours in the oak that wasn’t part of the bid.
From a safety standpoint, rigging and anchor points in a willow or cottonwood are going to be much different from those in an oak; and if Johnny can’t tell the trees apart, rather serious consequences could be the result. There are a wide variety of tools and resources available for tree identification, ranging from the OFG (original forest gangsta) books and guides to the cutting-edge apps on smart phones. But regardless of what tools might be used, some basic understanding of identifying features and principles for tree identification will help speed the learning process along.
Typically the first thing that will be noticed about the tree is how it is shaped. This, in the context of tree identification, refers to a species’ typical shape or outline; and though, in most cases, it should not be considered a definitive indicator of a tree’s species, as there is certainly more than a little variety among all individuals of the same species, it can certainly start the identification process in a general direction, particularly when viewed from a distance.
Getting closer into the tree, the bark is typically noticed next; and although it may not provide every bit of information needed to identify the tree, it can start weeding out the possibilities. The knowledge of different species’ typical bark texture, color, and other general characteristics can be quite valuable in tree identification; and is very useful with larger trees when a visual examination of leaves or buds is challenging. In some cases, trees are readily identifiable simply from their very distinctive bark, but caution should be employed as there are species where the bark can vary with age or environmental conditions.
Leaf arrangement is a topic that can be challenging to new tree identification students, as some species leaves may seem to have no pattern. But some minor study and attention to detail can help distinguish the different patterns and terms used to separate one species from another. This term refers to the pattern in which the leaves or needles are attached or “arranged” on the stem or twigs, and can often give the identifying party an excellent clue as to what tree species they should be considering. Leaf arrangement is typically referred to as one of three types: whorled, opposite, or alternate. A whorled leaf arrangement will have multiple leaves around the stem at the same spot, while an opposite one will have two leaves on either side of the stem at the same location, and in an alternate arrangement the leaves will be “staggered” or alternating on either side of the stem.
Although buds may seem to be a topic that won’t help with tree identification, they can actually be quite important. Tree identification in winter, or when leaves are simply not present, can be quite challenging; and knowledge of the form, shape, and structure of different species’ buds can be quite helpful in this regard. Obviously, the bud arrangement is going to fall into the same categories as the leaf arrangement previously discussed, but particular bud characteristics such as scale location or bud shape are very useful and can identify individual species once known and understood.
This identifying characteristic may not always be easily seen, but when it is, a good data collector will take full advantage of it. The pith is the interior wood structure of a twig on or from a particular tree, and can also offer information of value to the identifying arborist. Although, in many cases, the twigs may not be readily available, or their pith all that distinctive, trees such as a walnut and its pith, which has multiple small cells or chambers, are quite easily identified in this manner.
Leaves and needles are the “go to” method of tree identification. And although a thorough examination of tree leaves or needles for distinctive characteristics may seem easy and obvious, this method requires more than a small amount of knowledge of different terms and characteristics. These many terms and the characteristics they describe can seem confusing and contrary at first, but some time with a guidebook or online examples will help them become second nature.
Among these characteristics are ones such as whether a leaf is simple or compound; if simple, is its margin entire or lobed; if compound, is it pinnate or palmate; and many more. A simple leaf is just that, simply one leaf springing from a bud, while a compound leaf has multiple leaflets springing from its petiole which arises from a bud on the stem. A compound leaf that is pinnate has leaflets attached along its petiole, much like a feather, thus the name, while a palmate leaf can look like the fingers off the palm of a hand with leaflets attached at the end of the petiole. A simple leaf with an entire margin is one in which the edge of the leaf is smooth with no serration, while a lobed leaf has distinctive and severe indentations in its margin. Needles may appear singularly or in bunches of various numbers; and may also be scale or awl-like. All of these multiple characteristics provide the tree care professional with information that, once understood and deciphered, can provide the tree’s identification quite readily.
Fruits and flowers are identifying characteristics that have to be caught at the right time of year, but when present, can provide ready identification of an individual species. In the case of conifers, cones often linger on the ground or, in some cases, on the tree for an extended period of time; and, in larger trees, can provide evidence of what species the tree is even when the needles are far beyond view. (Care must be taken not to be misled by adjoining trees’ cones, or a mischievous squirrel that has chosen to confuse a climbing arborist by clever cone placement.)
The difficulties of learning the scientific, botanical or Latin names of trees has been the terror of more than a few tree care professionals’ existence; and more than a few simply refuse to do it, feeling it shows them to be a “Mr. or Ms. Fancy Britches.” Although learning the scientific names can be pretty challenging, it’s important to at least attempt to for several reasons. Common names cannot only be confusing in discussions with fellow professionals or customers, they can also be misleading, and sometimes result in incorrect treatments or work practices. There are many trees of extremely different species and even genus that have the same common name, leading to confusion; and other species whose common name misleads the user as to its true identity, such as firs that are not firs. Additionally, though no one need be fluent in Latin to take advantage of this feature, the scientific names of trees can, and often do, describe a characteristic of the tree. An example of this would be the Big-leaf maple whose scientific name is [ital>Acer macrophyllum<ITAL], P leaves.
This is obviously just a brief introduction to tree identification. After all, this is a subject that fills a vast number of print volumes, not to mention all kinds of bytes online. But, like so many subjects of knowledge in the tree care profession, a small start can quickly open up vast amounts of valuable information to the dedicated tree student. The basic terms and principles discussed here used in conjunction with a guidebook or smart phone app can help every crew member to get to a place where they not only know what kind of tree they are climbing, but also how strong and safe it may or may not be.
Michael “House” Tain is a contract climber, splicer, educator and writer associated with North American Training Solutions www.northamericantrainingsolutions.com and Arbor Canada Training and Education www.arborcanada.com. He is currently located in Lancaster, Ky., and can be reached via e-mail at firstname.lastname@example.org.