For diversity, simply record the number of different species. The importance value index (IVI) measures how dominant a species is in a given forest area. IVI of tree species is determined as the sum of relative frequency, relative density, and relative dominance :)

It solely depends on the sampling strategies of pre-specified objectives. If you are going to measure and estimate diversity of all plants (from grass to Tree), example by setting a 20X20 m plots, then for grass or herbs there needs to put nested plot of 1X1 m size and count all plant which

The calculation of Importance Value Index (IVI) and diversity parameters of bamboo forest involves several steps. First, the vegetation of the bamboo forest is sampled using a quadrat or plot-based method. The size of the quadrat or plot depends on the size and density of the bamboo forest. Second, the species present in each quadrat or plot are identified and recorded. Third, the abundance of each species is estimated by counting the number of individuals of each species in the quadrat or plot. Fourth, the basal area of each species is measured. Basal area is the cross-sectional area of the stem at breast height (1.3 m above the ground) and is used as a measure of the size of the individual trees. Finally, the IVI and diversity parameters are calculated using the following formulas:

• Importance Value Index (IVI) = Relative Density + Relative Frequency + Relative Dominance
• Species Diversity (H') = -Σ(pi)ln(pi)
• Species Evenness (J') = H'/ln(S)

where pi is the proportion of individuals in the ith species, S is the total number of species, and ln is the natural logarithm. IVI is a measure of the importance of a species in the bamboo forest and is calculated by summing the relative density, relative frequency, and relative dominance of each species. Species diversity (H') is a measure of the number of species and their relative abundance in the bamboo forest. Species evenness (J') is a measure of the relative abundance of each species in the bamboo forest. These parameters are useful for understanding the structure and composition of the bamboo forest and can be used to inform management and conservation efforts.

IVI is the measure of spatial value index of one particular species, simply termed as Importance Value Index. It is the relative measure of density, dominance and abundance of one species among the other species growing in any particular area. In any sampling area ( regardless of the sampling strategy), summation of the relative density, dominance, and abundance or frequency of occurrence of any species will determine its importance value index for that particular locality.