The Big Trees of Patuxent
Matthew C. Perry
Patuxent Wildlife Research Center
The trees stand tall at Patuxent - and indeed they should. Protected for over 75 years from lumbering and growing in one of the most fertile floodplains of North America, they've done okay for themselves. In the floodplain area there are trees that are approximately 135 years old. Their age is known because 65 years ago when the Government constructed a road through the floodplain many of the cut trees were aged at 70 years old, based on counting annual growth rings.
Some areas of Patuxent have small stands of trees that are probably over 200 years old, because these areas were never cut. They exist in remote areas on small islands within the multi-branched Patuxent River. These so-called "virgin forests" or old-growth forest contain some of the largest trees - the grandaddies of the forest.
The largest tree ever measured at Patuxent was on one of these islands (Beech Island). It was a yellow poplar (tulip-tree) with a trunk circumference of over 18 feet and a diameter of almost 6 feet. Unfortunately, this mammoth tree died in 1986, and only its rotten trunk remains. But don't despair for within a stone's throw is another yellow poplar only a few inches less in circumference and diameter. Folks, we're talking big!
Beech Island, as you might expect also has some large beech trees. The second largest beech tree (diameter 52") in the state stands proudly on the upstream end of this island, and has provided support for a red-shouldered hawk's nest for many years. The state's largest pignut hickory with a diameter of 33" and Patuxent's largest sweetgum with a 46" diameter, are also on the island.
Over the years Patuxent has claimed some U.S. record size trees based on official measurement rules of foresters. Botanist Neil Hotchkiss and his colleagues conducted the first big tree survey in the 1950s and resurveyed many trees in the 1960s. An overcup oak with a 5-foot diameter was the largest tree for its species for the whole United States. Unfortunately, this tree fell over in 1972 shortly after leafing out in the spring and now 34 years later still slowly rots on the forest floor. Several large overcups are within a short distance of the old champion and one is 4 feet 7 inches in diameter. In 1999, the largest overcup oak tree located in Maryland, which was in Cambridge, died and so now Patuxent has the largest for the state, and who knows maybe someday it will be the largest in the United States, setting another U.S. record for Patuxent.
Another old U.S. record was a river birch that measured almost 4 feet in diameter in the 1960s. This tree has not been found in recent years and probably has died and already returned to the forest soil. Many river birches are located along Cash Branch and the Patuxent River so new records are being developed all the time. Patuxent biologists have teamed with County foresters in Prince George's and Anne Arundel Counties and are presently looking for new record trees of these two species in the same areas where the U.S. champions were found.
Patuxent has also boasted about several State record trees and many Prince George’s County record trees in upland sites. A pitch pine with a diameter of 2 feet 6 inches was the largest in Maryland until it fell to the ground in 2002. Another one was found that measures 2 feet 2 inches in diameter. The northern catalpa at the Endangered Species Research Area near the Crane Chick Building is the third largest for the state and raises eyebrows with its 13-foot circumference and 4-foot diameter. One of Patuxent's red cedar trees is the second largest in the State with an 11.5-foot circumference and 3.5-foot diameter. A sweet cherry (diameter 34") was the second largest in Maryland, but is now dead. Two trees growing not far from the historic Snowden Hall and both state records are a sweetbay magnolia (diameter 8") and an exotic Japanese pagoda tree (diameter 35").
Official measurements have not been conducted on many trees, however, so there could be some interesting surprises. Many of Patuxent's big trees occur in the dense forest and, therefore, don't reach the diameter or canopy of those found growing in the open where they get more sun and less competition from other trees. To account for this bias from growing conditions, foresters use three measurements (diameter, height, and canopy cover) to score the big trees. By using this scoring system, a numerical value can be obtained that clearly shows what is the largest tree, but not necessarily the oldest.
Other trees at Patuxent that are of interest to foresters and naturalists include a sycamore (6 feet in diameter) growing in a damp site not far from the Little Patuxent River and a multi-trunked redbud which is 44" in diameter at the base, but only 13" in diameter for the largest trunk at breast height. A sycamore maple, which is only 12" in diameter, was unique because it is the only known one of its species in the county, but unfortunately the top fell due to vine cover in 2002, but now is recovering. A swamp white oak (3.5 feet in diameter), a swamp chestnut oak (4 feet in diameter), and a willow oak (5 feet in diameter), are all the survivors of disease, lightning, fire, flood, and drought.
But the trees of Patuxent are more than just records in a County of State Record Book, they are living stories that have witnessed many events. The willow oak at Snowden Hall is probably the tree that has witnessed most. The party of dignitaries for the dedication of Patuxent Research Refuge gathered under its branches in June 1939. Many employees have picnicked under its branches on warm days. The employees witnessed the emergence of black rat snakes every spring as the warmer temperature stimulated their body for another mating season. On one occasion a large black rat snake fell out of the tree and landed in the middle of a startled group of employees enjoying their lunch. On another occasion the staff observed a pair of black rat snakes as they carried on a very excited act of copulation. To the surprise of the onlookers the activity was so intense that the snakes lost their hold on the tree and came crashing to the ground. Lucille and Bill Stickel captured and marked many of the snakes from this tree over the years. Although the snake tree died in 1988 after the top fell down in a storm, Gary Heinz found a seedling of this tree and planted it at its base in 1989 as part of Patuxent's 50th anniversary celebration. The tree is now standing tall at 30 feet next to the rotting trunk of the original tree.
The white mulberry tree at Gabrielson Laboratory shaded many employees on hot summer days as they walked to and from work. In the summer of 2005, several employees noticed that one of the tree’s biggest branches, about a foot in diameter, was hanging very close to the sidewalk. The leaves brushed against staff as they hurried to and from work. The idea of trimming the branch back so it no longer was a nuisance entered many minds, but soon was forgotten and no action taken. What the staff did not realize was that the branch was not just extending its growth, but was slowly falling to the ground. This fact became quite evident when at about 6:30 AM on August 10, 2005, the branch came crashing to the ground as employees walked to work. Fortunately no one was under the branch, but Bird Banding Lab employee, Wendy Manear, was not far from it and witnessed and heard the thunderous crash. The branch apparently could no longer support itself with the increased summer moisture and growth. Wendy had planned to send the Facilities Department a request to trim the branch, but procrastinated one day too long!!
Many of the living trees of Patuxent have endured where other trees failed. They deserve our respect for surviving, but they also warrant our thanks for providing cleaner air and a more interesting environment for all humans to enjoy. Below is a list of the largest of every tree species that exists at Patuxent. It includes the exotic introduced ones and the native ones in the forest. The exotic ones were mostly planted in the 1940-50s as the Refuge was being developed and most are in the Headquarters area. The native ones are scattered throughout the Refuge in the many diverse habitats found here. Some are easy to find, but some offer a challenge. New entries are always welcomed, so get a tape measure and find and measure a tree. The circumference measurements can easily be converted to diameter by dividing by pi, which is that transcendental number (3.14) relating to the ratio of the circumference of a circle to the diameter of the circle. Good luck.
[Big Tree Table]