The City of Macon, Georgia contracted with Space Imaging to identify the extent and growth pattern of the Macon-Bibb County’s urban heat island (UHI). This was accomplished, in part, though the analysis of declining vegetation canopy.

Urban heat islands are created when forestland and other natural vegetation is replaced by buildings, roads, and other paved areas. This results in higher surface temperatures in urban areas, compared to the surrounding countryside. In order to identify and evaluate the Macon-Bibb County UHI, Space Imaging analyzed local and regional weather station data along with Landsat TM imagery that was captured in the spring and early summer of 1985, 1993, and 1997. The results of the UHI analysis were combined with the results of a previous canopy change study to identify any possible correlations between the UHI size and location and changes in the county’s tree canopy.

The results of this analysis indicated that the size and location of Macon-Bibb County’s urban heat island has expanded during the study time period. Further analysis of the UHI and canopy change data demonstrated that changes in the UHI are closely associated with changes in the area’s tree canopy. In general, as tree canopy is reduced, temperatures tend to increase while temperatures tend to decrease in response to increases in forest canopy. These findings have provided decision makers, planners, government officials, and the general public with a better understanding of how the UHI is created, how changes in tree canopy can affect the growth of the area’s UHI, and what can be done to help mitigate the harmful effects of the urban heat island effect.