Saving Campus Trees In 2024, the Morris Urban Forestry Consultant team began removing stem girdling roots (SGRs) that were hindering the growth of trees on Penn’s campus. SGRs are a threat to urban tree health, and by using Arc GIS mapping software they are able to track and prune these trees, saving them from decline.  Image Stem girdling roots can cut off the sap flow to the tree and eventually cause the tree to decline. Shown here is a campus Zelkova ( Zelkova Serrata ).  The Morris Arboretum & Gardens'  Urban Forestry Consultant team (MAUF) works closely with the Office of the University Architect and Operations & Maintenance departments in Facilities and Real Estate Services at the University of Pennsylvania to manage the 6,800 trees on campus. This includes assessing the condition of trees every year, improving management practices, and updating standards to ensure high quality tree care at all life stages.  In 2024, the Morris team began removing stem girdling roots (SGRs) that were hindering the growth of trees on Penn’s campus. SGRs are a threat to urban tree health, and by using Arc GIS mapping software we are able to track trees with SGRs and monitor them over time.  A tree may be girdled when a root grows in a position that crosses or wraps around the trunk. As the tree trunk grows and enlarges annually, the offending roots can gradually girdle or choke the flow of water and nutrients. This makes SGRs a primary cause of tree decline in built landscapes.  Image A map of girdling root remediation on campus. 110 trees received treatment this year.  Pruning girdling roots is a specialized task performed by arborists. It involves understanding the complex root systems of trees and how they interact with the surrounding environment. It also requires a keen eye and delicate touch to identify where the cut should take place, how deep a cut is necessary, and how many roots should be removed at one time. The objective is to remove as many as feasible without …

Elegy for the Lebanon Cedar For the last several decades, our majestic cedar of Lebanon trees ( Cedrus libani ) have struggled to survive our changing weather. In 1887, when John and Lydia started their Compton Estate, Lebanon cedar was considered a well-adapted plant for the Philadelphia region and was often planted as a featured specimen. We have had several Lebanon cedars in our collection, but only two remain from the original garden. Image Cedar of Lebanon ( Cedrus libani ) that was once located in between Exuberant Blooms and the Springhouse in the Azalea Meadow. For the last several decades, our majestic cedar of Lebanon trees ( Cedrus libani ) have struggled to survive our changing weather. This evergreen conifer is native to  the  mountainous regions of Lebanon, Syria, and Turkey. Young trees grow as strong, upright sentinels. As they age, they develop massive trunks, broad spreading crowns, and distinctive horizontal branching, making them magnificent specimens for parks and arboreta. In 1887, when John and Lydia started their Compton Estate, Lebanon cedar was considered a well-adapted plant for the Philadelphia region and was often planted as a featured specimen. We have had several Lebanon cedars in our collection, but only two remain from the original garden. Lebanon cedars, like many higher elevation conifers, have evolved a survival strategy of markedly slowing their growth and respiration rates during cool nights. This ability allows them to make maximum use of warm daylight temperatures to produce sugars and essentially go dormant during cool nights to conserve energy. This mechanism allows the trees to build up a surplus of stored energy over time. This energy, in the form of sugars, is then used to produce vigorous growth in what would normally be inhospitable environments. This strategy works in a high elevation environment where there are reliable cold nights, but it also predisposes this species to heat stress. When nighttime temperatures are …