LAI values for different types of plants are found in a Guidebook on its use in the Calculation of Green Plot Ratio ‘Leaf Area Index of Tropical Plants’ (NParks, 2009). The RP’s methodology aims to determine achievable GnPR values that can be incorporated in a building type through a series of design simulations and statistical analysis of the data derived from these simulations. Figure 1. shows the hyperbolic slow-to-sharp rising trend of GnPR with the assigned Total Cost (S$) from the Existing to the Ultimate scenarios. Average increase of the GnPR level from the Existing to the Ultimate scenario is observed as follows: