Contributed by Anthony Aiello, Gayle E. Maloney Director of Horticulture & Curator

One thing visitors may not think about when visiting the Morris Arboretum is the monetary value of its tree collection. At the risk of stating the obvious, as an arboretum, Morris Arboretum’s primary function is to serve as a museum of plants that focuses on trees and shrubs. And, as curator, Anthony Aiello’s role is to oversee the composition, care, and use of these living collections. Of the 11,985 accessioned plants throughout the Arboretum (not including those in the greenhouse), 4,127 of these are classified as trees, ranging from small, recently-planted seedlings, to vigorous teenage and maturing trees, all the way to impressive veteran specimens. Of these 4,127 trees, 63% have been planted since 1980 and approximately 50% of them have been planted in the past 25 years, indicating that it an actively managed collection. 

As a museum, Morris Arboretum’s tree collection is insured, and based on a valuation that was conducted in 2013, it has a total estimated value of $25 million, making the tree collection one of the top assets of the Arboretum. As with any asset, trees require care as they age, and it is the gap between Morris Arboretum’s existing resources and its overall maintenance needs that is the deferred maintenance for tree care.  As an example, if the arboretum were able to spend 1% of the total value annually on the care of its collection, it should be spending $250,000 each year on tree care. The good news is that there is a full-time arborist staff member plus an intern, and the arboretum is also able to contract out for arboriculture work throughout the year. This budget, however, is significantly less than $250,000, so as the annual maintenance budget lags, the deferred maintenance continues to accumulate, and there is a backlog of work that needs to be completed. 

Morris Arboretum is taking the next step in its tree care which is to put a value on this backlog of deferred work. There is currently a proposal to assess all of the trees in the collection by first, measuring the sizes of all of the trees and developing a ranking based on the potential hazard that they pose, and then estimating tree longevity and developing maintenance recommendations. Funds still need to be raised to complete this two-phased assessment, and once these are secured, Morris Arboretum can move to develop a comprehensive tree management plan. 

Simultaneously, the Arboretum is advancing its veteran tree care work, in other words, focusing on the management of its signature specimens. The recent loss of the beloved Bender oak and slow decline of the Engler beech served as a wake-up call to carefully monitor the arboretum’s existing veteran trees. A step towards this was an arborist "round-table" in January, during which a group of internal and external experts came up with recommendations for

Morris Arboretum’s 12 top trees. Based on this, it is moving ahead with work on seven of them and plans to continue the round-table process next year.

The tree collection is the foundation of the Morris Arboretum and is a fundamental aspect of its mission. It is essential to preserve, maintain, and grow the collection in order to achieve the goals of research, horticulture, and education. With continued efforts to focus and improve its arboriculture, Morris Arboretum can ensure that this resource continues for future generations.