Optimal methods for producing saplings from seed

[DEHattaway]

I was curious what the optimal methods for producing a high quality forest style were from seed; I know that generally different ages and thus sizes of trees are used, however, I have several Water Oaks I started this spring and I'm not sure I'll start more next year that wanted to make into a forest in about 3-5 years or so of growing them out. Currently they're all about the same size and same vigour which will likely result in a set of trees that are too similar in size without actively keeping some smaller than others. For specifically planning out the material that I need to develop for what I hope to be a roughly local show quality bonsai down the road, would it be more optimal to start more seeds for the next 2-4 years or so to get a wider range of development and perhaps back up trees in case some turn out poorly over time or would just sticking to those that I have currently and keeping some in smaller pots than others to keep them more dwarfed work just as well for a really nice planting. What in general is the most optimal way of turning seeds into high quality trees of with a range of caliper and height for eventual composition as a high quality forest planting. Is it necessary to have a much wider range of material than the bare minimum for producing a composition(what I have currently +/- 2-4 trees extra)? Will varied age trees impact the quality(positively or negatively) or would only height and caliper be a factor? Would I do anything specific regarding pruning practices that might be a bit different from the development of a single trunk style tree compared to producing forest material? would growing them in the ground improve the material quality compared to pots? how long should I grow them out for(I'm planning to have atleast 7-9 trees and a fairly large planting in a big forest pot I have)? would bigger trees and trunks potentially produce a better composition(older material as opposed to young saplings). Would I want to consider gathering potential additional materials for the planting now(I'm considering making it a slight bit of landscape style too with rocks, dwarf plants(specifically thinking azaleas) that look like bushes below the canapy)?

Thanks

 

[Wires_Guy_wires]

I have all my seedlings in super shallow trays to stunt their growth in the first couple years. This way I get easy branching down low and a reasonable idea of their vigor.
I start in batches of a 100 or more. Because in shallow trays there's also the issue of easy deaths.

After 2-4 years, I plant them out individually in pots or the ground and they take off in the next year. Usually by that point there are some differences in height and thickness and some pruning would do the rest.

Is that the best method? No. Probably not. It does work though, and it's low effort and high reward.

 

[DEHattaway]

I have all my seedlings in super shallow trays to stunt their growth in the first couple years. This way I get easy branching down low and a reasonable idea of their vigor.
I start in batches of a 100 or more. Because in shallow trays there's also the issue of easy deaths.

After 2-4 years, I plant them out individually in pots or the ground and they take off in the next year. Usually by that point there are some differences in height and thickness and some pruning would do the rest.

Is that the best method? No. Probably not. It does work though, and it's low effort and high reward.

This sounds quite effective for most tree species in particular maples though probably not optimal for oaks due to their need to have the tap root chopped early to produce a decent root base. I'm currently testing Root maker pots for the first year and the results are impressive and heavily cut down on early root pruning requirements; I can reasonably grow anything out fully in a 1 gallon pot before it needs it's first root pruning. the first root pruning(year 2-3 in the spring depending on species) seems like it would be little more than bare rooting and selectively cutting bad/overly strong roots and immediately potting into a 3 gallon afterwards. The effects on root base are especially effective and useful for oaks. The best method I've found though for amazing root bases especially on plants that root vigorously such as elms are by growing them out with plenty of unimpeded tap root and radial root spread such as a deep storage tub with drainage holes for the first year then take a washer and shove it to about 1" down the tap root and bury extra deep in a 1 gallon can the swelling and future root spread are top notch in 70-80+% of cases the few that aren't are usually due to too little water or not buried deep enough to get root growth for the tap root layering. based on the results on an elm I have putting them in a root maker pot would make the root base that much better by keeping excessively long aggressive roots more in check. I have some shallow small trays with holes suitable for growing seedlings that might work for oak tap roots too so I'll start a few of those next year too and see what results I get. Oaks are especially difficult to manage if they're not started in the ground since inception as field grown material or you wait longer than the 2nd spring to cut the tap root; the washer method works but doesn't always produce heavy root development. So far the best method for oaks I've found is root maker propagation trays. Your method definately sounds perfect for other species though.

 

[sorce]

Use one seed and take cuttings to make the rest.

Same genes.

Sorce

 

[Shibui]

Not sure there is just one optimal method to grow forest trees. I've seen great groups grown by a number of different methods from throw seed in a tray through arrange small seedlings to arrange older, larger trunks.
You'll definitely want different height and thickness but that can be achieved either by different ages or by restricting growth of some to slow development. Both will work.
I find it good to have extra trees when it comes time to assemble. Good groups are not just a bunch of random trunks planted together. For good results trunks need to have some relationship, similar shapes or bends. Branches need to be in the correct places. Spots to chop some trunks down if required and still have a replacement leader that grows in the required direction.
Some of the above can be achieved with wire and bending but I still find plenty of candidates that just won't work. I'd say I would like to have 20% extra trunks for most species to achieve a superior group. Obviously some species respond to pruning better so it is easier to make them fit than other species.

To hedge your bets why not start some more each year. You'll need to grow out the current crop for a few years anyway so provided you have enough space some extras are likely to be very useful come the assembly.