This is called monoecious. If male and female flowers occur on different trees, it is called dioecious. Every seed bearing tree and shrub has an irregular crop production from year to year. A pattern begins to form. Forecasting a bumper crop is easier to do once the pattern is known.
Climatic conditions vary from year to year.
For example, rainfall, temperature, light and wind can either enhance or restrain the process of seed crop production. How to Forecast Forecasting is done when the cones or fruit begin to appear several weeks after the flowering stage. Most conifers can be forecasted from the last week of June to the first week of July. The Pine family takes two years to develop cones. This allows a forecast for the current year cone crop and a forecast for the following year.