Seed treatment of Pinus koraiensis before seedling cultivation?

The method of seed treatment before seedling cultivation of Pinus koraiensis: the seed shell of Pinus koraiensis is dense and thick, covered with wax, not permeable and breathable, and contains tannin and other germination inhibitory substances, so that it is difficult for seed embryo to germinate. Therefore, the seeds should be germinated before sowing. The commonly used false bud methods are as follows:

First, the method of overwintering in the open air: that is, soak the seeds in cold water for 2 to 3 days in autumn, remove and mix 2 to 3 times wet sand and put them in the open cellar. The kiln site should be located in a place with high and dry terrain and good drainage. The cellar is 1.2 to 1.5 meters deep and 1.2 to 2 meters wide. When the mixed sand seeds are 20 to 30 meters thick from the mouth of the pit, a grass is ventilated every 2 to 3 meters, and then covered with a layer of sand, which is piled into a 1-meter-high mound. This method promotes sprouting evenly, emerges early after spring sowing, and thrives neatly.

Second, indoor natural accumulation method: in mid-and late August, after soaking Korean pine seeds for 1 to 2 days, mix twice the wet sand, so that the moisture content is about 60%, and the pile is 30 to 40 cm thick and placed indoors. Pile it into 60 cm thick when it is cold, and water it to freeze it. Turn it over before spring sowing next year to make it warm and wet evenly.

Third, rapid sprouting method: that is, about 40 days before sowing, soak the seeds in warm water of 50 degrees Celsius, fully stir, after natural cooling, soak for a week, and change the clear water once a day. When the kernels become milky white, remove the seeds and mix them with 2 to 3 times wet sand and spread them in the leeward to the sun. Pile up the sand every night, cover it with plastic film, and spread it out the next day. In order to accelerate germination, you can also put indoor heating, so that the sand to maintain 20 to 25 degrees Celsius, turn several times a day, and maintain a certain degree of humidity. When there are 1/3 cracks in the seeds, the seeds can be sown.