Examining Tree Size and Age

The Colebrook Land Conservancy is compiling a list of the largest or most interesting trees in town.  Flyers were circulated around Colebrook in 2006 asking for the public’s input, and now that the results are in, a map and text will be made available sharing this information.

The first thing usually asked about an old, large tree is “How old is it?â€�  It is almost impossible to answer this due to the difficulty or impossibility in counting growth rings.  In temperate climates such as ours, trees produce annual growth rings, but unless the tree is cut down, there is no way to make an accurate determination, as trees of the same species will vary greatly in the amount of wood fiber they produce annually depending upon where they are growing.  Rock maples, for example, growing in or next to wetlands will have a slower growth rate than another maple whose roots are in richer, well-drained soil, even though they may have started from seeds from the same parent tree.

There is a device called a corer that is able to bore into a tree and extract a plug that will allow for the counting of the annual growth rings, but this process has drawbacks. Coring can be detrimental to the well being of the tree, as it could allow bacteria to gain assess; the center of the tree is not necessarily where the center of the growth rings are, and most corers are 20 inches long, allowing for a core to be extracted having a radius of 20 inches or a diameter of 40 inches, or a circumference of 10 feet (120 inches).  

This would be a pretty good-sized tree, but probably not in contention as a champion tree.  Many times the largest trees will prove to have rotten centers, which permanently destroys the growth record, so that leaves any reasonable estimate as to age to finding written records that mention when a specific tree or row of trees were planted.  

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It is not uncommon in Colebrook and the surrounding towns to find rows of trees, generally either red oak, rock maple or white ash, growing along the highway.  When one of these trees is cut down, or something happens that allows for the determination of age, it is reasonable to assume the others are of the same age.  A case in point is the maple trees that grew in front of the parsonage in Colebrook Center.  Two of these giants had to be removed in 2005, due to the infirmities of age.  A count of growth rings revealed approximately 145 rings, indicating that the survivors began life approximately around the beginning of the Civil War.

One of the most celebrated stands of trees in Connecticut, the stand of white pine in Cornwall known as “cathedralpPines,â€� was almost completely destroyed by a tornado in 1980.  These trees were up to 150 feet in height and a count of growth rings revealed that some were 300 years old with the bulk being 200 years.

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The oldest named tree in the state is the colonial pine, growing on the Phelps Research Area in North Colebrook. This white pine, when first noticed by Arah Phelps shortly after he purchased the property in 1787, was a mature tree having 13 main branches.  Arah, recently having completed his service to his country at the close of the Revolutionary War, had a strong sense of national and state pride, and the fact that his large 13-branched pine had the same number of branches as the new nation had states, named it the colonial pine and recorded it in his journal.

In 2007, this tree is approximately 120 feet tall, and has a circumference of 194 inches (16 feet, 2 inches), giving it a diameter just over 5 feet.  As it was named 220 years before, and was probably not less than 100 years old when Arah Phelps bought his land, its age would be approximately the same as the cathedral pines in Cornwall.  This tree is rapidly approaching the end of its life, unfortunately, as the eastern face of the tree has died, and of course along with that goes the root system on that side as well.  This places the tree at great risk if a strong easterly wind were to come along.

The American Forestry Association (AFA) has established a point system for measuring and comparing trees.  The formula involves adding together the following parameters to get a single number representing the size of each specimen:

AFA points = trunk circumference in inches at 4.5 feet (54 inches) above ground + tree height in feet + ¼ the average branch spread in feet.  This method is useful for comparing trees of different shapes.

Using this formula, the colonial pine, with a circumference of 194 inches plus 120 feet in elevation plus one quarter the branch spread of 47 feet, yields an AFA number of 326. This compares well with the largest white pine in Connecticut, which is a tree in Morris in the White Memorial Foundation grounds having an AFA rating of 350 points (in 1988).

Another white pine, this one easily observed from an auto, is located at the sharp curve on Sandy Brook Road near the Colebrook Town Garage.  Its height is 135 feet, its circumference 146 inches and its branch spread is 58 feet, giving an AFA rating of 295.5.

Our list includes Colebrook trees regardless of whether they are indigenous (native) or introduced, as so many species have been introduced that are tolerant to our climate that they probably outnumber the native species.  This is particularly true with the coniferous trees, as the only native evergreens growing here when the first settlers arrived were white pine, hemlock and tamarack (or larch).  There doesn’t seem to be any road in town that does not have some form of spruce or introduced pine.  Several respondents to our inquiry nominated the spruce trees next to the Colebrook Store and the Congregational church in the Center.  Other nominations were the Japanese Dogwoods at the top of Deer Hill Road and the ornamental Red Maple in front of the Old South School (corner of Smith Hill Road and Old North Road).

More than one resident has come forward with the information that they have discovered an enormous tree (usually red oak) deep in the forest on their land and that this has to be the largest such tree in town.  The fact is that when these hills were all striptd clear of forest, a few trees were left scattered about to provide shade for the sheep or other farm animals.  As the years past and the forest returned, these behemoths became embedded in the new forest.  The only way to establish ranking is to measure the tree, apply the AFA numbering system to it and make comparisons.

If you happen upon members of the Colebrook Land Conservancy while walking along our nature trails, you will note that one of the many encumbrances they will be weighted down with will be a 100-foot steel tape!

Bob Grigg is the town historian in Colebrook.