The short answer is yes but the long answer is a little more involved. Here are some considerations to consider when planting trees from seed. Collect seed when it is mature. A good indicator of maturity is when the seed is naturally falling from the trees.
Most trees mature in the fall.
Most tree seed is not mature and will not immediately germinate when it falls from the tree. This characteristic helps protect the species. If the seed germinated after falling in the fall, the tree seedlings would not be hardened off sufficiently to withstand an Iowa winter. To finish maturing, tree seed must be exposed to a period of moist cold. This stratification process may be accomplished most readily by fall planting.