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ASLA-NCC

Awards

2013 Awards

Research, Planning, Analysis and Communication

Merit Award

Genentech Campus Monterey Cypress Tree Research Study
South San Francisco, California
MPA Design, San Francisco
Principal and Landscape Architect: David W. Nelson
Client: Genentech

After photo of same group of cypress showing greater than 48” growth, during the first 16 months of continuous growth through the first winter after planting.
Before photo of first group of Monterey Cypress planted at windy upper campus October and November 2011, in 24” (center), 36” (left) and 48” (right) box sizes.
After photo of the same two Monterey Cypress with growth to March 2013.
Before photo of two Monterey Cypress planted bayside December 2011.
Four pressure compensating 0.25 GPM surface bubblers and 18” and 36” deep root bubblers at installation.
The nursery growers recommended saw cutting the root ball ¼ distance to trunk, to eliminate encircling roots. This process is done at each box size shift at the nursery, and will not hurt the cypress.
Tree drain hole and larger planting holes.
The soil scientist prescribed 67.5% loamy sand blended with 25% lava rock and 7.5% organic amendment top 18”, no organic amendment below 18”.
Result of the research was an improved Cypress tree planting detail with larger plant holes 6’ x 6’ minimum, loamy sand backfill, sub drainage, top of root ball 4” above adjacent finish grade, saw-cut root balls, increased irrigation to four surface and two deep root bubblers, and mulch held back to a minimum of 4” from trunk.
Soil plugs pulled where cypress had died, on a 2:1 slope, showed water build up 6” – 8” deep at interface of clay subsoil. 6” below this saturation, the subsoil became dry.
The soil scientist pulled plugs to understand the soil and drainage conditions.  At this 40 year old cypress grove, the soil is dry, loose and loamy sand.
Cypress canker was a contributing factor in the loss of 65% of 200 cypress planted 20 years ago. The arborist indicated that cypress, under optimum growing conditions; survive with the disease for decades with occasional branch die back, which can be pruned away. Research was needed to mitigate the disease for future plantings.

The marine microclimate at a 200 acre bay side Biotech Campus was perfect for growing Northern California’s iconic Monterey Cypress. 120 of 184 cypress planted in the 90’s died . When the company decided to re-populate the campus with cypress, the Landscape Architect recommended a research project utilizing an Arborist, Soil Scientist and Nursery Growers to determine cause of cypress failure and design new planting process to increase survival. The Arborist verified Cypress canker would not kill the cypress under optimal growing conditions.

Reseach found existing poor drainage, heavy clay subsoils and wetness at the transition layer. This condition lead designing new planting details with extra large planting holes, sub-drainage, loamy sand back-fill with organic amendment, saw-cutting rootballs, elevating rootballs and a new six point irrigation system.

This knowledge and new planting details were applied to 440 Monterey Cypress planted since 2011 achieving 36″ per year growth rate and no failures.