LAS ARBOLEDAS, A NEW TOWN IN HAVANA, CUBA

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Pedestrian Community Las Arboledas is designed to be a pedestrian community which is connected to the larger urban area by bus (and auto). The pedestrian community provides an intimate social environment where children, for example, can walk to school, to the store, or to visit friends without crossing busy streets. Homes are sheltered from noise with only quiet pedestrian paths passing in front of the homes. Apartments are grouped into neighborhood clusters of about 50  apartments with public community space in front including meeting spaces, small plazas, walkways, and green areas. The community is connected internally by pedestrian paths and with other parts of the city by bus (or car). No through streets cross and disrupt the community. A ring road circles the community providing easy vehicular access to and from other parts of the city. A series of finger roads provide vehicular access to the interior of the community, while protecting it from fast traffic.

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The site is quite beautiful with numerous large trees, mango orchards, and rolling hills. One of our objectives is the preservation of this landscape and its integration with the new community. A plan which has accommodated the trees and natural topography of a site, is automatically in closer touch with the site and has accounted for a number of factors which might otherwise go overlooked. This constraint alone forces better and more sensitive design.

However, in discussing the value of the natural landscape, we often think in aesthetic terms and these concerns can seem small in the face of the bulldozer. Builders often prefer to clear all the trees and level the ground, especially when heavy equipment is used, arguing that it is cheaper. Since we feel that destruction of the natural environment is in fact a gross economic error, we have pointed out some of the more concrete benefits of preserving it.


Microclimate: Landscaping for Energy Savings

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In Cuba's tropical climate, buildings can become very hot and uncomfortable. As people's incomes rise, they will attempt to provide air conditioning for hot buildings. This can be a large energy consumer that not only increases the environmental problems associated with energy use, but competes with more basic economic development for energy resources. One of our objectives has been to design buildings that are naturally cool and thereby eliminate this potential energy drain. The landscape can play an important role in cooling buildings and in creating a more comfortable microclimate. Part of this effect is illustrated rather clearly in a series of tests done by the U.S. National Bureau of Standards in the southern U.S. (NBS Report 10373, February 1, 1971) These tests measured the surface temperatures of a blacktop surface and a grass covered surface during the 24 hours of the day. On a summer afternoon, when the air temperature had risen to 90 degrees, the surface of the blacktop had risen to over 130 degrees. In addition it stored this heat and so remained hotter than the surrounding air even during the night. In contrast, a grass covered surface nearby barely reached 90 degrees at its hottest and during most of the day and night was more than 12 degrees cooler than the surrounding air. Figure 6, shows the average monthly temperatures throughout the year for the blacktop surface, the grass surface, and the surrounding air. The blacktop is consistently hotter than the air, while the grass is consistently cooler. During the summer the grass was more than 10 degrees cooler than the blacktop. In fact it is well known that cities, with these asphalt "solar collectors", are hotter than the surrounding rural areas.

Shaded Streets

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Trees and plants are important in creating and maintaining a thermally comfortable environment. These particular tests suggest that we should minimize paved surfaces. But we cannot eliminate them entirely, so what can we do? One answer is to shade the streets with large trees. But these trees cost money to plant and maintain. In addition they can easily take 20 years or more to reach the required size. But our site already has many large trees with a great value, all we have to do is preserve them. This then is one of many motives for taking care of the existing natural setting.