Joseph Trimble Rothrock

The Chief Agitator


Happy Birthday, Joseph Trimble Rothrock (Books By This Author) was born in 1839.

Plagued by sickness as a child, Rothrock felt the call of the great outdoors,

“I just had to go to the woods. Throughout my entire life, I have sought the ‘out of doors’ as a refuge against impending physical ills."


Rothrock went to Harvard and worked daily in the private herbarium of Asa Gray, who visited Rothrock's hometown to collect botanical specimens. Of Dr. Gray, Rothrock said, 

“[He] was kindness personified, though a strict disciplinarian and a most merciless critic of a student's work. I owe more to him than to any other man, and I never think of him without veneration."


He also studied geology under Louis Agassiz, who became his friend. (Agassi's motto was, "study nature, not books")

Rothrock suspended his studies at Harvard to fight in the Civil War. His right thigh and hand were wounded at Fredricksburg in 1862 (Burnside's fight), and he shook hands with President Lincoln at an army hospital. Later in his life, in a photograph of Rothrock called "The old white pine and the Father of Forestry," he stands in front of the trunk of a giant white pine. With his signature long white beard and kind effect, the gentle expert's right hand is grasping a walking stick. The photo notes say that his right little finger was amputated at Fredricksburg.

Rothrock attempted to return to Harvard but discovered that his professors - including Asa Gray - had formed a military company and wanted to serve in the war. Rothrock insisted that Dr. Gray was too old to serve, took his place in the company, and served for another three months.

Rothrock taught botany and went on to become a surgeon. He went on several important expeditions and wrote the Flora of Alaska. 

His passion for forestry ignited when he was named a Michaux Lecturer on Forestry, and he took a nine-month sabbatical to study under renowned botanist Anton Debary at the University of Strasbourg in Germany.  

In 1893, Rothrock began an expedition to investigate the challenges affecting Pennsylvania's forests, or "Penn's Woods," as he called them. For two years, Rothrock and his associate engineer, William Shunk, investigated the condition of forests in Pennsylvania.

Destructive forest fires were all too common during the logging era, and long before "Smokey the Bear," Rothrock led the effort to prevent forest fires. Rothrock said that

“almost every forest fire is the result of ignorance, carelessness, or crime, and that there is some one to punish for it.”


Rothrock reported the problems of deforestation; he also educated the public on tree propagation and forest restoration. Facing opposition from farmers and timber barons, Rothrock's relentless focus on forestry aimed at making a policy change. In 1901, he wrote,

“Twenty years ago I began agitation upon the forestry question, I have kept at it ever since; […] you have no idea of the amount of work it requires to change a generation from tree destroyers to tree restorers; it is something akin to a second birth.”


In 1909, at age seventy, Rothrock sold his vast herbarium and library to the Field Museum of Natural History in Chicago. The collection reportedly contained 22,207 specimens, including specimens named in his honor:  Artemisia Rothrockia, Halenia Rothrockii, Nama Rothrockii, Pentstemon Rothrockii, Stachys Rothrockii, Toivnsendia Rothrockii and from Lower California, a genus Rothrockia which belongs to the family Asclepiadaceae.

Rothrock State Forest in Pennsylvania is also named in his honor, and Joseph Trimble Rothrock's birthday - April 9th - is commemorated annually in Pennsylvania schools as Arbor Day.



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Joseph Trimble Rothrock Courtesy Pennsylvania State Archive
Joseph Trimble Rothrock Courtesy Pennsylvania State Archive
Joseph Trimble Rothrock Portrait
Joseph Trimble Rothrock Portrait
Rothrock Vista
Rothrock Vista


  1. Donald Horn on May 7, 2021 at 2:48 pm

    Great article but one off the wall question. What was the name of his beagle companion?

    • The Daily Gardener on May 7, 2021 at 9:20 pm

      Hi Donald –
      Great question. His pup was named Rab – short for rabbit. 🙂


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