Pennsylvania State Forest School (1903 – 1929)
- 1903 – The Arboretum is established with the founding of the Pennsylvania State Forest Academy
- 1905 – Arbor Day – Students collect over 400 specimens, representing 30 species, for inclusion in the arboretum
- 1910 – Arboretum work slowed with the arrival of chestnut blight in the area
- 1914 – Eighteen non-native conifer species, donated by Mira Dock, are planted in the arboretum
- 1915 – At this time the arboretum contained more than 50 exotic species
- 1917-1919 – Arboretum work halted due to student involvement in World War I
- 1920 – Nine bur oaks planted to commemorate students who were killed in World War I
- 1918-1929 – Professor George S. Perry acquires many new specimens and creates the arboretums first species indexing and numbering system
- 1921 – Norway spruce stands planted in the woodlots left from the iron forge days
- 1925a – Forty new species arrive from government nurseries around the country as well as 45 species received from Japan from Professor Fujioka
- 1925b – Gifford Pinchot donates an Oriental spruce
- 1929a – At this time the arboretum contained over 100 exotic species
- 1929b – The PA Forest School merges with the Pennsylvania State University and the arboretum was placed under the supervision of the PA Department of Forests and Waters
PA Department of Forests and Waters (1929 – 1958)
- 1930 – At this time the arboretum contained 193 non-native species
- 1935 – The arboretum was reported as containing 450 different species
- 1938-1942 – Extensive survey and retagging was undertaken to revise and expand Perry’s original notes
- 1942 – J.E. Aughanbaugh publishes “A Catalog of Woody Plants of the Mont Alto State Forest and Arboretum” which listed nearly 1,500 specimens representing 53 families, 125 genera, and 420 species
- 1941-1945 – Arboretum activities curtailed due to World War II
- 1946 – A comprehensive survey of the arboretum was completed which listed 1,485 tagged specimens
- 1947-1958 – Correspondence between William Pfeiffer of Mont Alto and Everett Logue, D.D.S. concerning hybrid oaks
- 1949 – Everett Logue donates 42 hybrid oaks which are planted in the arboretum
- 1958 – Responsibility for the arboretum transfers from the Department of Forests and Waters to the Penn State School of Forestry
Penn State Mont Alto (1958 – Present)
- 1963 – The Mont Alto campus becomes part of the Penn State Commonwealth Campus and a two-year associate degree in Forest Technology is established
- 1964 – Forest Technician Club founded which begins an arboretum revitalization project (new identification numbers were given to all specimens and a new survey conducted)
- 1965 – The forestry club logs a total of 741 man-hours on the arboretum survey
- 1967 – Re-tagging and surveying ends with the publication of the “Index to the Mont Alto Campus Arboretum – Preliminary Report” by Robert W. Douglass which lists 725 tagged specimens representing 119 genera and more than 300 species
- 1988 – Inventory of original arboretum specimens completed
- 2008 – Bartlett Tree Experts completes a survey of all arboretum specimens and creates a searchable online map
- 2013a – Historical survey of original specimens and online map updating completed
- 2013b – A website is created for The Arboretum at Penn State Mont Alto
- 2017 – A walking virtual tour is started for The Arboretum
- 2018 – The previous website is incorporated as a full section into the Penn State Mont Alto campus website
- Current – Maps of specific trees continue to be updated as changes are made in The Arboretum