186 

 measuring 20 m on a side (total area = 400 m^. Some gardeners precisely determined this area using 

 a tape measure, while others estimated this area, for example, by counting paces. A precise 

 measurement of size was important to gardeners because they often contracted out certain phases of the 

 work and used the area worked, instead of an hourly salary, as the basis for determining the payment. 



Garden size for the seven selected gardens used to monitor crop phenology (see below) was 

 calculated from measurements of the garden edges and their bearings. Garden edge lengths were 

 measured with a tape measure to within 1 m. Garden edge bearings were measured with a hand-held 

 compass to within 2 degrees. An outline of the garden was made (scale 1; 1000), and the area enclosed 

 was measured with a compensating polar planimeter. 



Gardeners reported the distance and location of their gardens during the interview by indicating 

 the route taken, making reference to nearby landmarks, and referring to locations of nearby gardens. 

 The accuracy of distance estimates greatly benefitted due to the occurrence of numbered road markers 

 at intervals of 1 km along Mexican Route 307 (see Figure 2-5). Based on this information, aerial 

 photographs, and my familiarity with the area, garden locations were plotted on a base map (scale 

 1:100,000). Individual garden distances from X-Hazil Sur were calculated to within 0.1 km using the 

 water tank at the western edge of X-Hazil Sur as the reference point. The water tank was used because 

 it is a permanent structure and is indicated on many published maps. Distance measurements for 

 gardens near X-Hazil Sur or those close to roads or other landmarks probably were accurate to within 

 0.5 km, while distances for the others probably were accurate to within 1 km. 



Garden Type and Years of Previous Use 



The number of years during which a garden is used is important in determining the rates at 

 which new areas are converted to gardens and gardens are placed in fallow. This will have a direct 

 impact on wildlife and their use of the area. If gardens are planted but a single year, the rate of 

 conversion is much greater than if gardens are used 3-4 y in a row. If an area has a relatively low 

 population density of gardeners and a relatively low forest conversion rate, this rate will not be of 



