The center double row of trees, known as the tree allée, was first planted in 1881 as part of a larger campus tree-planting effort. This occurred nearly 30 years before the Oval as it is known today was proposed in the 1910 Master Plan by landscape architect W.W. Parce.

Many trees from the early planting remain, while others have been replaced over time and have grown to sizes comparable to the originals.

Elm trees surrounding the exterior of the Oval were planted in successive annual plantings between 1922 and 1927. Many of these trees eventually grew larger than trees from the original 1881 planting.

The 1881 and 1920s plantings appear to have been seedling-grown American elms. Unlike many clonal American elm varieties sold through the nursery industry today, each seedling tree is genetically unique.

As a result, individual historic Oval trees may display distinctive characteristics — or, as some tree enthusiasts might describe them, individual personalities.

The Oval trees have survived many severe fall and winter ice and snow events, but two major periods presented especially serious threats to the collection.

Dutch Elm Disease became a major risk after reaching Colorado in the 1970s. Without active management and sanitation measures, the disease can be fatal. Although most Oval elms survived, trees have been lost over the years.

Elms are monitored for symptoms. When infection is confirmed, affected trees are removed and separated from neighboring trees through trenching because the extensive root systems of mature trees may intertwine or graft together, allowing disease to move between trees.

During the 1990s, studies also identified the Oval trees as being in decline. Limited maintenance funding and intensive use of the Oval for events contributed to vulnerable conditions, particularly through soil compaction.

A steering committee considered competing plans for the Oval. One proposed replacing all trees with 98 new elms in the historic pattern. Another proposed introducing multiple species and age classes while retaining existing elms and preserving the historic composition.

Neither proposal was fully implemented. Subsequent management efforts have helped place the Oval trees in a more sustainable condition while preserving the historic character of one of CSU’s most iconic spaces.

• Limiting events on the Oval has helped reduce soil compaction. Certain non-CSU events formerly held on the grounds were relocated.
• Permanent structures, including benches, are not installed on the Oval, and objects are not hung from tree branches.
• The Oval remains free of lighting and electrical receptacles because extensive trenching required for utilities could damage tree roots and shorten tree life.
• Trees receive annual treatment to control scale insects.
• Trees are continually monitored for Dutch Elm Disease during the growing season.
• Dutch Elm Disease-resistant and scale-resistant elms are planted when older trees are lost, while maintaining the historic Oval pattern.
• Oval elms are pruned on a three-year cycle to support tree health and campus safety.

Sustaining the Oval trees costs more than $50,000 annually. Annual scale-insect treatments cost approximately $30,000, while the most recent three-year pruning cycle cited on the current page cost approximately $130,000.

Proceeds from the Oval Preservation Fund directly support these expenses but currently cover only a portion of the annual cost.

The Oval Preservation Fund helps preserve CSU’s existing historic elm trees in a safe and healthy condition for future generations.

As trees are lost due to age, disease, or storm damage, the fund also helps support replacement elms so the historic composition of the Oval can continue into the future.