Sustainability Statistics


  • The project redevelops the underutilized outdoor space at the base of Allen Center, a 1970’s office complex in downtown Houston.
  • The space was made more accessible through the creation of various outdoor spaces.


  • 155 trees were planted, including overcup oak, allee elm, and Chinese pistache.
  • 63 trees were saved.
  • Native and adaptive plant types were used, including sandi-leaf fig, iris, and Japanese yew.
  • The project minimizes pesticide and fertilizer use.
  • Mycorrhizal fungi was implemented in the soil mix to provide increased water and nutrient absorption for the planting. In turn, the planting provides the fungi with necessary carbohydrates.
  • Plants are allowed to go to seed/flower life.
  • The project avoids annual planting.


  • 48% of outdoor surfaces are permeable.
  • The site design mitigates runoff.
  • Trees have the potential for intercepting 109,000 gallons of water which are equivalent to the water usage for 1,090 American residents for one day.*

Carbon, Energy + Air

  • The trees sequester 26,160 pounds of carbon annually, which offset driving 35,586 miles in an average car.**
  • The trees reduce the temperature of the plaza up to 10 degrees Fahrenheit.
  • During construction, pollutants were controlled and retained.
  • Exposure to environmental tobacco smoke was minimized through designated smoke-free zones and prohibited smoking on-site.


  • There is a predicted increase in the property value due to project installation.
  • Maintenance savings were considered in the design, by choosing low-maintenance plant types.


  • The design creates a pedestrian space in the predominantly concrete environment of downtown. The trees give the space a human scale while offering the utilitarian benefit of shade for cooling.
  • The project supports alternative modes of transportation, with a bus stop at the edge of the site and bike parking.
  • The project provides optimal site accessibility, safety, and wayfinding through added signage.


* The tree average for water interception is 500 gallons. American’s use an average of 100 gallons of water per day (EPA’s water trivia facts)
**120 pounds of CO2 per tree annually (This number is based on an average from the National Tree Benefits Calculator) One car produces an average of 8,320 pounds of CO2 per year. Each vehicle drives an average of 11,318 miles per year. (The Code of Federal Regulations - 40 CFR 600.113)
The Allen Center
The Allen Center
The Allen Center
The Allen Center
The Allen Center
The Allen Center
The Allen Center
The Allen Center
The Allen Center

The Allen Center Sustainability Statistics The Allen Center