I examined the effects of soil and slope conditions on canopy dynamics in terms of openness and leaf area index through time as measured by hemispherical photography. Specifically, I compared alluvial versus residual soil and slope versus plateau and flat plots in an old-growth tropical wet forest in Costa Rica. No significant effects of slope were found for any estimator of canopy coverage in any analysis. Soil type approached significance as a single factor and several soil*year interactions were highly significant. In addition, I found highly significant inter-annual variation in all analyses that was concordant on all plot types. This is the first long-term study to document substantial inter-annual variation in canopy cover for a tropical wet forest. These patterns are a combination of seasonal changes in leaf area, forest dynamics resulting from gap formation and closure, and inter-annual variation in leaf area coverage caused by climate variation.