Stanford Trees

Stanford Trees

Stanford is known for its abundance of trees that are spread across the campus. Our Arborist and Tree Crew strives to maintain our urban forest of trees for everyone to enjoy.

Significant Trees

What is a significant tree? It is a tree selected as outstanding and therefore deserving of special protection because of either rarity, age, or historical importance. Significant trees present today on the campus of Stanford University. 

Transplanted Tree Program

This program started in January 1996. The objective was to save trees that otherwise would have been cut and removed from the vicinity of proposed new developments throughout the university campus. In certain cases, some trees have also been relocated from open spaces like the Arboretum to areas in need of trees. In addition, a substantial amount of trees moved were Canary Island palms supplied by outside contractors to replace some specimens that have died.

This effort has been part of the horticultural program of the Grounds Department. One of the original tasks was the development of a data base where Transplanted Tree inventory information has been recorded for each individual tree. This includes botanical and common names, date moved, dbh, height, vigor rating, monitoring dates, watering frequencies (irrigation or hand), and overall health. The data is linked to maps created with GIS technology. All trees are mapped for easy reference and follow ups.

The success or failure of this type of program relies primarily on monitoring the trees for a period of at least 10 years. The transplanted tree population has been monitored on a weekly, every 2 weeks, every 4 weeks, every eight weeks and annual frequencies, conditional on the length of time from the tree's move to its new location or any additional, special needs the individual tree may require.

Since this program started, over 1150 trees have been moved as of 2015. The predominant species is Quercus agrifolia (Coast live oak) with 460 trees representing 40% of the population. Thus our observations based on our historical data focus primarily on the Quercus agrifolia.The remaining 690 trees are composed of Olea, Sequuoia, Phoenix and Washingtonia palms, Pistachia, Pinus and some other genera with less presence, including other species of oaks.

Eucalyptus Species for Landscape Situations

Eucalyptus trees have a long history in California. They were first introduced from Australia in the late 1800s, and many different species have been planted throughout the state. This has not occurred without problems; for example, eucalyptus have displaced native species in certain habitats and have themselves suffered from several pest epidemics. Three important categories when considering eucalyptus trees for landscape use are lawn tolerance, hardiness, and pest problems. With these considerations in mind, we have prepared the chart below for use in this region. We hope this information will be useful to landscape designers, architects and planners for use in this region.

The chart lists eucalyptus species available in California nurseries in 15 gallon or 24" box size; their height, width, cold tolerance, water needs, lawn tolerance and pests. Three pests in particular have devastated eucalyptus in California: red gum lerp psyllid, eucalyptus long-horned borer and tortoise beetle. Their resistance or susceptibility to these pests is noted in the chart.

Eucalyptus Selection Chart

To find out more information about each tree, click on the botanical name in the chart.

Sources of information used to prepare this chart include the Encyclopedia of Australian Plants Suitable for Cultivation, by W. Rodger Elliot and David L. Jones, and the two volume set Eucalyptus, by Stan Kelly. Cultural information available is limited, and the main sources referenced are the Sunset Western Garden Book, the WOCALS Guide to Estimating Irrigation Water Needs of Landscape Plantings in California (The Landscape Coefficient Method and WUCOLS III), and Bob Perry's Landscape Plants for Western Regions. Pest information is available online at UC Statewide Integrated Pest Management Program.

Red gum lerp psyllid (Glycaspis brimblecombei) is a small sucking insect that lives and feeds on the leaves of certain species of Eucalyptus. Adults and immature insects are found feeding year-round, the adults in the open and the immatures protected under a sugary cone called a "lerp". This feeding causes leaf drop that can defoliate and kill the hardest-hit trees, and sugary honeydew excreted by the insects drips down from the canopy and promotes the growth of sooty mold. The best control of these insects is to provide optimal growing conditions to the host trees. A biological control agent has been released, but it is too early to tell how effective this wasp will be. For more information, see (link to Psyllid Infestation on Stanford Campus in Horticultural Subjects Archive)

Eucalyptus long-horned borers (Phoracantha semipunctata and P. recurva) are beetles whose larvae bore into the wood of blue gum and several other eucalyptus. This boring causes wilting, limb dieback and sometimes death of the affected tree. Several beetle generations occur a year, and stressed or wounded (recently pruned) trees are more at risk. A successful biological control agent is available, and it should be used in conjunction with providing the best growing conditions for affected trees and properly handling Eucalyptus wood.

Eucalyptus tortoise beetle (Trachymela sloaneri) is a leaf-feeding beetle whose host preferences have not been well documented. The adults and larvae chew notches along leaf edges and may eat the terminal growth of new shoots. Because they are nocturnal and often active high up in the canopy, they may be difficult to detect. The recommended management for this pest is to provide the best growing conditions for the affected tree. A biological control agent has been released, but its effectiveness is not yet known.