When interpreting the pollen record, there are many factors which must be considered prior to the interpretation of the past vegetation.
The quantities of pollen produced will differ depending on the species:
Trees and tall shrubs are higher pollen producers than smaller plants. As well, wind-pollinated species produce more pollen than insect pollinated species.
EX: Pine and Birch are wind pollinated and as a result they produce much more than Maples and Basswood, which are insect pollinated species (E.C. Pielou, 1991).
Different pollen's also vary in buoyancy which affects the distances which they can travel. The previous page illustrates the bladders of the Lodge Pole Pine which makes it much more buoyant.
As a result there are numerous problems in translating pollen frequencies into vegetation reconstructions due to the great differences between the quantity of pollen produced and preserved for different species.