In one aspect, the invention provides a method of modulating the development stage of strobili growing on a gymnosperm tree comprising: (a) installing a protective covering over one more strobili bud(s), wherein the type of protective covering is selected to delay or advance strobili development and (b) maintaining the protective covering over the strobili bud(s) for a time period sufficient to delay or advance the development stage of the covered strobili buds in comparison to the development stage of naturally growing, uncovered, control strobili.