140th Pennsylvania Group

What These Trees Witnessed

Figure P-1: multiple white oaks grew in very tight cluster in the late 19th century just a few feet behind the monument to the 140th Pennsylvania on the Loop at Stony Hill. Such close proximity likely explains the very slow growth of the surviving two trees, whose roots have always been forced to compete for the nutrients and water in the rocky soil beneath it. The 1897 photograph was taken by William H. Tipton.

The initial fighting in the Wheatfield and Rose Woods on the second day of the Battle of Gettysburg had been fierce, but Confederate numbers eventually told, and the elements of the Third and Fifth Corps which had been holding the sectior had been finally swept off the field by Kershaw’s South Carolinians and Anderson’s Georgians. In response, Brig. Gen. John C. Caldwell’s Second Corps Division arrived to stem the tide. Amongst his three brigades was that of Brig. Gen. Samuel K. Zook, whose four regiments, totaling nearly 1000 men, entered Stony Hill, crashing into Kershaw’s brigade.

Zook’s largest regiment was the 140th Pennsylvania, comprised of just over 500 soldiers, more than half of the brigade. The 140th was to lose almost half of its men today, as well as its regimental and brigade commander.

Immediately behind the monument of the 140th Pennsylvania grow two medium-sized white oak trees, both of which were already a few inches in diameter, and thus likely 30-40 feet tall, on July 2, 1863. The tree closer to the memorial is slightly larger than the one behind it.

The two trees appear together in an 1897 photograph of William Tipton’s. A first glance at the image may suggest to the viewer that the trees are much too small to have been around in 1863, 36 years earlier. However, the two trees, growing in such close proximity, are natural competitors for resources, and this would have led to their slow growth rate over the years. The math tells us that these two trees were extremely likely to have born a few decades before the Battle of Gettysburg.


The two trees were both first recognized as appearing in the 1897 photograph by Greg Gober. The author’s subsequent calculations first suggested that the two were likely witness trees.

Witness Tree #1

Brig. Gen. Samuel K. Zook Witness Tree

Tree Species: white oak
Circumference 2023: 77.5”
Diameter: 24.7”
Calculated Average Growth Rate: 8.5 years / inch diameter
Estimated age: 190 years
Estimated diameter in 1863: 4”
GPS: 39.797520 N, 77.245525 W

Brig. Gen. Samuel K. Zook (1821-1863). This good likeness of the general appeared in William Powell’s 1893 publication, Officers of the Army and Navy (Volunteer) Who Served in the Civil War.

The General Zook Tree is nearly 25″ in diameter. The ratio of its diameter in 1897:2022 is 0.34-0.35, which means that its diameter in the Tipton photo is about 8.5″. The average growth rate for the intervening years for the tree has thus been a glacial 7.8 years to grow an inch of diameter. Assuming a similar growth rate in its early years, the tree can be estimated to have first sprouted in about 1830. This gives us a large enough cushion to conclude with confidence that, even if the tree enjoyed a bit of faster growth in its early years, it is a Witness Tree, though admittedly a smaller one.

The tree is named for the stern but handsome Brig. Gen. Samuel K. Zook (middle name Kosciuszko), commander of the Third Brigade, First Division, Second Corps at Gettysburg. Zook was born in 1822 in Chester County, Pennsylvania, into a Mennonite family, which when Samuel was still young moved to the ancient family homestead situated at Valley Forge on General Nathanael Greene’s campground. Still a teenager, Zook took employment with the Philadelphia office of the Washington and Telegraph Company, and so impressed his superiors that he was at some point appointed superintendent of the company. The promotion came with a move to New York, where he joined, and by 1861 had risen to be lieutenant colonel of, a state militia organization, the Sixth Regiment, Governor’s Guard. (1)

The monument to Brig. Gen. Samuel K. Zook, set on the Wheatfield Road, was one of the earlier markers to be placed on the battlefield. Dedicated in 1882, the monument, Tom Huntington tells us in his Guide to Gettysburg Battlefield Monuments, was carved from marble harvested from the general’s father’s farm. The early William Tipton photo is thought to have been taken within a year or so after the erection of the monument.

When war was declared, the regiment joined the Union army at Alexandria, VA. At the expiration of the regiment’s 3-month enlistment period, Zook recruited the 57th New York Volunteer Infantry, and was appointed the unit’s first colonel in October 1861. Zook was specially commended by General Winfield Scott Hancock for his role in leading his men in the attack on Marye’s Heights at Fredericksburg, and was promoted to brigadier general in March 1863. (2)

At Gettysburg, Zook rode into the fray on Stony Hill on horseback, making him a natural target for the South Carolinians facing him. Receiving multiple wounds, including a fatal one in the abdomen, Zook was taken to a field hospital on the Baltimore Pike, where he died the next day. (3) The general’s remains were brought to Norristown in Pennsylvania for burial at Montgomery Cemetery, where he was to be joined by General Hancock upon the latter’s death in 1886.

A detailed look at Zook’s participation and death at Gettysburg can be found here in an article by Diane Loski for the Gettysburg Experience website.

(1) Powell, William H. Officers of the Army and Navy (Volunteer) Who Served in the Civil War. Philadelphia: L.R. Hamersly & Co., 1893. P. 264.
(2) Warner, Ezra J. Generals in Blue. Baton Rouge: Louisiana State University Press, 1996. Pp. 576-7.
(3) Welsh, Jack D. Medical Histories of Union Generals. Kent, OH: The Kent State University Press, 1996. P. 380.

Witness Tree #2

Col. Richard P. Roberts (140th PA) Witness Tree

Col. Richard P. Roberts (1820-1863). This sketch of the colonel was published in the 1912 regimental history.

Tree Species: white oak
Circumference 2023: 73”
Diameter: 23.3”
Calculated Average Growth Rate: 7.9 years / inch diameter
Estimated age: 180-185 years
Estimated diameter in 1863: 3”
GPS: 39.797520 N, 77.245525 W

Interesting image of the 140th Pennsylvania’s battle flag; from the regimental history, published in 1912.

Witness Tree #2, growing just a few inches behind the Zook Tree, is slightly smaller than its fellow, with a similar slow growth rate, suggesting it probably first sprouted a decade after the larger tree. The ratio of its diameter 1897:2022 is 0.32, which means that its diameter in the Tipton photo is 7.4″. With an average growth rate over the last 126 years of about 7.94 years to grow each inch of diameter, the tree birth date, assuming a constant growth rate in its early years, calculates to be about 1840, and its diameter at the time of the battle could have been about 3″, almost certainly a sapling. While it is possible that its growth rate in its early years was faster than during its maturity, bringing its birth date much closer to 1863, there is a decent enough cushion of time to give it a very good chance of being a witness tree. You can of course make that decision for yourself.

The tree is named for Col. Richard P. Roberts (middle name Petit), commander of the 140th Pennsylvania. Roberts was born in Beaver County, PA, where he grew up on the family farm. Studying law, Roberts was admitted to the bar in 1848, and subsequently rose so well in the estimation of his peers that he was elected District Attorney for the county. Roberts married and had three daughter, one of whom, Emma, was, during the war, so well regarded by the 140th Pennsylvania that she was dubbed “Daughter of the Regiment”. (4)

In the summer of 1862, Roberts raised three companies of men which were mustered into the newly-formed 140th Pennsylvania Volunteer Infantry, with Roberts appointed colonel of the regiment. The 140th received its baptism in battle in May 1863 at the Battle of Chancellorsville, where eight companies under the direct command of Col. Roberts “met every demand of the most exacting test of courage, with steadiness and alacrity.”

When General Zook was wounded, Colonel Roberts took over command of the brigade. The regimental history notes that Roberts “was in the fore-front [of the brigade] at every moment;” Soon after Roberts was shot through the heart, instantly killed. A beloved man, Roberts’ body was brought back to his home in Beaver County, PA, for burial. For more on Col. Roberts, read his biography in the 140th’s regimental history, printed in 1912, here.

(4) All biographical material for this sketch of Col. Roberts was adapted from the regimental history, written by Robert L. Stewart, published in 1912; see pages 360-5.

Photograph of Col. Roberts which was also published in the 1912 regimental biography.

The 140th Pennsylvania Volunteer Infantry’s plaque on the Pennsylvania Memorial on Cemetery Ridge in Gettysburg; this image was printed in the regimental history.