It’s easier than you think! Follow Nature’s method and you can grow a forest in a seed flat with very little effort.
Here in Alaska, our two most common trees are Birch and Spruce. In the fall both distribute their seeds and birch bracts quite readily in the forest, your yard, on streets and sidewalks, etc. You’ve seen the evidence but may not have recognized these tiny shapes as seeds. This material is known as “mast”. The term mast may refer to fruit, nuts, seeds, acorns, etc. of plants in the forest.
There are five species of birch in Alaska. Two are dwarf species, and there are three tree species: Alaska Paper Birch (Betula neoalaskana), Western Paper Birch (Betula papyrifera), and Kenai Birch (Betula kenaica). All of these species hybridize where their ranges overlap. ?
If possible, collect seed from the area where you are going to plant or from an area with the same growing conditions and of similar elevation. Information on planting and caring for seedlings and trees is available from the Division of Forestry.
To grow your own forest all you need to do is set out a seed flat with any soil you have, including used potting soil or garden soil. You will leave this flat outdoors until spring, then make sure it is getting gently watered every few days, as shallow containers tend to dry out quicker than large pots. In a few weeks, you may see some green.
This method is known as a “seed trap” and you may be rewarded with a variety of species that the Universe provides, from weeds to wildflowers. If you place the seed trap near a tree, you will pretty much be guaranteed to get seeds from that tree. I would leave any seedlings that grow in the flat for a couple of years until they are 1-2 inches tall and are easier to handle for transplanting into larger pots, such as a one-gallon size. The seedlings can stay in the larger pots for several years. Plant in the ground when 12-18 inches tall.
You can also intentionally plant tree seeds. Just collect some mature cones of spruce or pine and leave them in a paper bag for a couple of weeks or so to dry out. Shake the bag and you should see dozens of seeds fall to the bottom. Just plant them thinly in a seed flat as above. Cover with a thin layer of sand or grit to keep the seeds in place.
In the Anchorage area where I live, Black and White Spruce are the most common conifers. In nearby Girdwood, Lutz spruce are common. Lutz spruce is a hybrid of white and Sitka spruce. Sitka Spruces are found in southeast Alaska. White Spruce are easy to grow, but Black Spruce need fire to disperse their seeds.
Dissemination of Seeds
In Nature seeds travel in the wind or are spread by birds, squirrels and other animals. “Hitchhiker” seeds attach themselves to fur or socks. “Floaters” move by water, such as a coconut rolling down a beach and into the waves. ”Tummy Travelers” get eaten by animals and ejected far and wide. That’s the problem with the Prunus padus, European Bird Cherry here is Alaska. It has become invasive.