Why are there no pine nuts in the pine cones found in the park?

Pine trees in a broad sense refer to common conifers in Pinaceae, while real pine trees in a narrow sense belong to the genus Pinaceae, which is particularly simple to identify. They are all bundles of needles, such as Pinus tabulaeformis, Pinus massoniana, Pinus bungeana and Pinus armandii, which are common in Shaanxi. Among them, Pinus tabulaeformis and Pinus massoniana are in bundles of two needles, Pinus bungeana is in bundles of three needles and Pinus armandii is in bundles of five needles. Pine is the main tree species that produce wood and rosin in the world. Pine bark can be cut to collect turpentine, the liquid obtained by distillation is called turpentine, and the remaining solid resin is called rosin. Domestic rosin mainly comes from Pinus massoniana. People who study stringed instruments must be familiar with rosin. I am an electrical major, and I often need to solder circuit boards, so I have to dip rosin in an electric soldering iron and then heat the wire.

Let's take a look at the familiar pinecone (or pinecone). The megaspore leaves of Pinaceae plants have two forms, one with ovules is called pearl scale, and the other with ovules is called bract scale, which are spirally arranged and separated from each other. After the cone matures, the bead scale is renamed as seed scale, and there are two seeds on the ventral surface. At maturity, the seed scales open, releasing (usually) winged seeds.

After the cones of pine trees mature, the seed scales lignify and persist, which is a typical pine cone we are familiar with, while the seed scales of cedar trees fall off after the cones mature, so think about it. Haven't you seen the pine cones around the cedar? Because when they mature, the scales will fall off.

Some species of Pinus plants can produce large and full seeds, and the pine nuts sold in China are basically from Korean pine and Huashan pine. Most seeds are spread by the wind. Their pine nuts are usually small and winged, and the scales of mature seeds open in dry weather, releasing mini pine nuts. So the pine nuts you found in the pine cone have flown away in the right weather, which is why we have never found pine nuts in the pine cone.