Working With Existing Trees III

The Peace Garden, California State University - Fresno:  Working with ZGF Architects, I redesigned the Peace Garden in a simple and restrained series of gestures that redefine the site as a series of outdoor rooms, each anchored by one of the four major peace monuments.  Preservation of eighteen existing Canary Island pine trees (Pinus canariensis) was a key design feature.  The Canary Island Pines also provided shade which is a premium in the hot and dry California Central Valley; they shaded a central outdoor campus space, and surrounding buildings reducing the high cost of air conditioning. The Canary Island pines were mature and measured over 100’ in height.  The weak roots of the trees were near the surface of the ground, due to turf and sprinkler irrigation, and the soils were compacted due to pedestrian traffic and weekly mowing. 

To save the Canary Island pines and renovate the Peace Garden around them the site was hand-excavated with air spades around the roots of the trees and backfilled with structural soils for proper drainage and aeration, reinvigorating the trees’ root structures.  To draw the roots away from the surface, a below-grade irrigation system was installed. Structural soils also protected the root systems from new paved campus walkways and a fire lane was re-located away from the Canary Island pine trees to protect them from vehicular campus traffic and fire trucks.

Work in China

I have over ten years of design and management experience on projects in China, both as the Landscape Architect and as Urban Designer, firms that have included Peter Walker and Partners and ZGF Architects.   Projects have focused on high-density mixed use urban projects, including Taioing Qiao Park, Shanghai, and Silo City, Beijing.  I have also been involved with the creation of government studies and developer master plans in Chengdu, Da Lian, Hefei, Yantai, Xiang and Yibin

 This work has allowed me to develop an urban landscape form and narrative that is supportive of our clients’ energetic and optimistic vision for high-density living environments in China.  The following sketches and plans from these projects are illustrative of my body China of work.   

Working with Existing Tree II

A significant focus of my landscape architectural work on college and institutional campuses is the re-forestation of mature campus landscapes.  The example below describes technical and design issues on the University of Redlands Historic Quad.  Note that the oaks on the University of Redlands Historic Quad are the native leafy evergreen tree of the high desert and foothill regions of south eastern California.  Groves of native oaks form the main local California native community, providing habitat for birds, native plants and mammals.  Native oaks are the main contributor to the region’s biomass as well. 

University of Redlands:  The most visible asset of the campus is the Quad and the century old grove of Coast Live Oaks (Quercus Agrifolia).  The Quad oak trees define views between historic campus buildings and views to the north and east mountains, which visually center the campus in the San Bernardino region.   The oak trees on the Quad are all suffering from multiple infestations of borers and diseases.  The oaks are all the same age and within the next ten years the decline of the oaks will become visible.

Working with the university’s stakeholders, an approach was developed to inter-plant new trees that will establish and take the place of the mature oaks as they decline.  A major challenge to the replacement of the historic oaks is the inter-planted tree spacing layout of the young oaks.  There is a range of grid layouts that replace the historic tree spacing, and the one shown (Image #2) is the current status.

Working with Existing Trees

A significant focus of my landscape architectural work on college and institutional campuses is the integration of mature trees into architectural and landscape projects.  Special skills and expertise are required of a multi-discipline team of designers, arborists, geotechnical, civil, structural engineers and construction contractors working together to insure the preservation of full-grown, mature trees.  Damage to the roots and other parts of mature trees does not become apparent in the trees’ appearance for up to five years after the work has been done.  Therefore, the best measure of success is to revisit the trees at least five years after project completion and check for signs of decline.  The work shown below at Stanford University is ten years old.  

Stanford University:  Images show the process of saving a heritage-quality Coast Live Oak (Quercus Agrifolia) threatened by the realignment of Campus Drive on the Stanford campus.  Construction at the base of the oak tree is shown in Image #1.  Construction included excavation, removal of soils around the oak by hand and air spade, placement and compaction of structural soils, careful grading, and engineering and construction of a retaining wall for the super-elevated edge of the roadway, with the specific focus of protecting the roots of the oak tree. Image #2 shows the condition of the Oak Tree 10 years after the work was accomplished.