Many equations that calculate the necessary chemical formulation of active ingredient (ai) per acre in Christmas tree fields do not take into account the volume of trees within the area to be sprayed. Spraying the correct amount of chemical is crucial for efficacy: spraying trees with a lower ai per acre can reduce efficacy, and spraying trees with too much ai per acre is money and labor lost and can be environmentally irresponsible. This worksheet aids in the calculation of a backpack mist sprayer, such as a Stihl SR branded backpack mist sprayer.