Why is it hard to collect data for a pyramid of biomass?

It is hard to collect data for a pyramid of biomass because it requires accurate measurements of the total biomass at each trophic level, which can be challenging to obtain. Additionally, the data collection process may involve destructive sampling methods that can be time-consuming and labor-intensive. Moreover, the availability of technology and resources for estimating biomass accurately may also pose difficulties in data collection for a pyramid of biomass.