IMG_5713.JPGThe first iteration of the tree enclosure has been dismantled, but not without leaving its mark.

Keep an eye open for the next iteration.


Tree Sounding


How do we gain access to tree-ness? How are symptoms diagnosed from within the inaccessibility of a tree–its history, its girth, etc? These are some of the broader landscape forensic questions we have been asking throughout the term.

This past week we worked with the German physicist, inventor, and tree expert Frank Rinn to begin to map the interior of a tree using sound.

Yup, sound.

Frank has invented and manufactures a system for sonic tomography–the measurement of a tree’s cross-sectional density by means of sound-waves. IMG_5407

With a girdle of 15+ sensors, the tree is sounded in a sort of arboreal perambulation–where each sensor is lightly tapped 5 times as the propagation time of the sound wave is  measured at each of the other sensors. The resulting measurement is a map of the speed of sound through the medium of the tree.


Each vector in the chart to the left measures the relative time it took for the sound wave to reach a corresponding sensor. The resulting diagram of greens, oranges, yellows, pinks, and reds, is simply a visual coding of speed–with green being relatively fast, and red/pink being relatively slow (or nonexistent).

This set of measurement is then interpolated to form a density map on in the tomogram on the right. Here, a visualization of the wood density–and, perhaps, through experience in interpretation, strength–is charted in a communicable form.

As Frank is quick to point out that, while this tomographic system certainly communicates fundamental scientific information about the trees in question, this sort of imagining is fundamentally a political tool. In the politics of the visible, and in the politics of urban street-trees in particular, the ability to communicate the non-visible, the subcutaneous, allows urban foresters an immediate way to construct a slightly more informed landscape public.

At stake in this sort of measurement is the politics of diagnosis. Landscape is uniquely interpretable as a symptom: a symptom of ecological pressures, historical processes, and design intents. The traces of these (geo)histories, embedded as they are within the body of the tree, provide symptoms that can be diagnosed through a range of landscape forensic activities. Much of what we have been up to in this course is exactly this. Landscape forensics as method.


The Politics of Topography

Olmsted Brothers Preliminary Plan for Washington University, 1895. Courtesy Washington University in St. Louis Archives

In 1895, the Board of Trustees of Washington University hired the landscape architecture firm of Olmsted, Olmsted & Elliot to develop a preliminary plan for a new campus site at the edge of the city. At that time, Forest Park was indeed a forested park, and the hilltop campus was a site of sharp gullies and savanna-like grasses and trees.

Topography of the WashU site, 1899. In all the competition entries, this topographic site-plan was only to be found in the files of the Olmsted entry. Courtesy WashU Archives.

construction_lanscapesInto this landscape, Olmsted Brothers projected a picturesque campus with a sweeping entry that both followed the contours of the site as well as their longstanding design tropes of meandering paths and jaunty disposition of buildings. But within this pastoral vision, they also set the tone for what would become the defining characteristics of the campus–a set of nested outdoor rooms or courts, arranged orderly along the hilltop site.olmstead_revised_planBut within four years, having been invited to take part in the final, international competition for the master-plan of the campus, and with the site having doubled in size, the meandering, topographically responsive entry of Olmsted’s preliminary scheme gave way to a centralized plan linking Forest Park and the University. Here, then, lies the fate of this site. Every entry into the competition–from Olmsted to Cope & Stewardson, and from Cass Gilbert to McKim, Meade & White–projected this axis across the contours of the undulating landscape. To think otherwise, it seems, was to give-in to the specificity of place and context. And here, perhaps, lies a prolegomenon to the politics of topography.

View looking east from the hilltop during construction, 1899. Note the forest of Forest Park. Courtesy WashU Archives.

The Hatchet


In 1906, one year after the first and only Tree Planting Day on the WashU campus, the University Yearbook adopted this logo.

An incredible day today in the University Archives and Special Collections. A complete privilege to be paging through the original Olmsted campus plans, the adopted Cope & Stewardson plans, the failed campus competition entries, and the early 20th century tree inventories. Special thanks to University Archivist Sonya Rooney for her introduction to the collection and invaluable assistance.

Certainly more to come….

Under the soil, life


Last week we began our inquiry into tree life under the ground with a careful, suggestive introduction to root/fungus relationships with biologist and plant ecologist Scot Mangan. A specialist in what he describes as the ‘biology of dirt,’ Scott introduced into our conversation a range of ways to understand the mutualism of mycorrhizal relationships as well as the selectivity of fungal pathogens. Ecto-mycorrhizal associations are those tuned to the sort of oaks we are working with, as we follow a range of issues related to differential allocation, root architecture, and basics of sub-surface growth. In the photo above, Scott leads a discussion in reading the possible signs of the presence of mycorrhizal  associations as we view the stunted, blunt growth of fine roots.

Arboreal Convening

onetree_treeworkaheadWe have been studying the biological functioning and ecological interrelationships of a tree, but they also exist as uniquely social and legal objects in the landscape. For whom does a tree do its work? What work, exactly, is it doing? And who is responsible when it fails? Trees relationship to law, risk, and property confer a unique sort of status to the public nature of ownership, and challenge some of the more abiding categories of boundary definition and maintenance.

There is a certain poetry in the ambivalent language of risk: imminent, probable, possible, improbable. These are the categories of contingency that an arborist brings to their assessment of a tree. Duty of care speaks to the legal pact we enter into when we plant and maintain a tree, as we dance around the threshold of the probable and the possible.

David Gunn of the Missouri Botanical Garden ascending tree with double rope technique.

The conversation and field-session was led by a cast of the region’s top tree experts: Skip Kincaid (former Commissioner of Forestry for the city of St. Louis, now with Hanson’s Trees), Ben Chu (Horticulture Supervisor at Missouri Botanical Gardens), Kent Theiling (Horticulturalist at WashU), Bill Spradley (President of Trees, Forests, Landscapes), David Gunn (Arborist at Missouri Botanical Gardens), and Russel (Forestry Division of St. Louis). In addition, we were joined by ecologist Doug Ladd, artist Marilee Keys, biologist Scott Mangan, and outdoor educator Guy Mott. A sincere and resounding thank you to all!

Weathering a February flurry, as Ben Chu narrates the climb.