The Arborist and Tree Care Program

The Arboretum Foundation fully funds the Arborist and Tree Care Program, which is essential to the health and vigor of Washington Park Arboretum’s woody plant collections. The program finances the salaries of a full-time Arborist and a full-time Arborist Ground Assistant, along with their equipment, supplies, and contract support.

Background

Devastating snowstorms swept across Seattle in late 1990, bringing widespread damage to the Washington Park Arboretum. In response, the Arboretum Foundation contributed funds to hire Lou Stubecki, a certified arborist, for a period of three years. By the end of the three years, Lou had successfully convinced everyone that this allotment of time was not nearly enough. Apart from snowstorm cleanup, hazard trees were accumulating, specimens were being neglected, and new trees were going untrained. The Arboretum needed a permanent arborist presence, and so a program was created.

Today, the Arborist and Tree Care Program funds the salaries of a full-time Arborist and full-time Arborist Ground Assistant and has three main functions: 1) care and maintenance of the woody plants in the Washington Park Arboretum, 2) assessment and appraisal of trees, and 3) instruction.

Care and Maintenance of the Woody Plants

The arborists prune the core collections according to season. For example, the Mountain Ashes (Sorbus species) are pruned in winter and the Hollies (Ilex species) in summer. Close records are kept on the collections and their condition. While pruning and caring for the collections, the arborists perform risk assessment, which aids in determining whether precautionary actions need be taken. Certain trees need cabling or bracing, for instance.

The arborists also manage the “native matrix,” a tool for monitoring the health and safety of native trees in the Arboretum. These trees, some of which are nearly 100 years old, are monitored closely, especially after storm events. The arborists use a rating system for determining actions that should be taken with these trees – cabling, bracing, removal, etc.

Another significant responsibility of the arborists is managing pests and their impact on the collections. Mulching and composting, aerating soil, and applications of beneficial fungi are just some of the tools used to discourage pests and maintain the health and vigor of the tree collections.

Assessment and Appraisal

When new construction or planting happens in the Arboretum, certain trees or collections of trees need special protection, if not removal. The upcoming SR-520 bridge replacement, for example, will force the removal of many trees on Foster Island. The arborist team will work on assessing the value of these damaged or removed specimens, which is valuable information for mitigation.

Instruction

The arborists provide undergraduate instruction to students at University of Washington’s College of the Environment.

How You Can Help

You can help sustain the Arboretum’s world-class plant collections by making a restricted donation to our Arborist and Tree Care Program. Make a secure online donation or call our Development Department at 206-325-4510 for more information.