Table 1. Explanatory variables and associated hypotheses for analyses of forest change in Puerto Rico.
Explanatory Variables Data Source Hypothesized
Relationship
Rationale
Socioeconomic
Population density
(1980, 1990)
U.S. Census + Defor
- Refor
Higher population density will be associated with greater land use intensity.
Population density change
(1980-1990, 1990-2000)
U.S. Census + Defor
- Refor
Urban-rural migration may drive deforestation for suburban development (MacDonald and Rudel 2005).
Normalized per capita income
(1980, 1990)
U.S. Census + Defor
- Refor
Rising local incomes may be associated with higher local land use intensity and suburbanization (Margo 1992).
Normalized income change
(1980-1990, 1990-2000)
U.S. Census + Defor
- Refor
Short-term increases in local income may reflect suburban development (Parés-Ramos et al. 2008).
Percent of area in reserve/protected area GAP (Gould et al. 2007) - Defor
+ Refor
Protected areas can deter forest cover change (Helmer 2004).
Biophysical
Life zones USGS (2009) w/ ↑Moisture,
- Defor
+ Refor
Precipitation is likely to affect vegetation dynamics and favor regrowth (Daly et al. 2003) or alternatively, reforestation may be slower in drier areas because of fires (Brandeis et al. 2007).
Median slope USGS (2009) - Defor
+ Refor
Slope affects development and agricultural cost (Turner et al. 2009, Crk et al. 2009).
Median soil agricultural capacity (1 is most fertile, 10 is least fertile) USGS NRCS (2007) + Defor
- Refor
Marginal lands are often the first areas to reforest because they are more likely to be abandoned than areas with high quality soil (Mather and Needle 1998).
Total forest cover
(1977, 1991)
IITF/USDA Forest Service + Refor By facilitating seed dispersal to abandoned sites, the extent and spatial distribution of forest cover can influence the rate of forest recovery (Thomlinson et al. 1996, Helmer et al. 2008, Crk. et al. 2009).

Per capita income data for 1980 only available at the municipality scale.
IITF = International Institute of Tropical Forestry