I want to estimate the amount of carbon that is sequestering by the vegetation of an urban park in Dhaka, Bangladesh. Here I attached an article document which describes a method of estimation. It is much more understandable for me to follow.
The method you mention is developed by USFS and is a rapid assessment method. It is reasonable to use the general method. Given that much of the estimates are based on tree type and climate in USA, I recommend modifying to fit to the tree species in the urban park you mention. Looks like you are translating the method to a tropical situation. Refer to allometric studies in tropical conditions and you can modify those methods. Here is one study on tropical species.
Article Height-diameter allometry and above ground biomass in tropic...
Allometric relationship for estimating above-ground biomass of ...