Collected Elm Progression

[99 Mile Creek]

There is a technique for doing in ground root pruning, but cutting the taproot should absolutely be left for last. If the tree has really expansive, thick roots, you can encourage fine root growth at the right time of year by digging a channel around the tree and filling it with a looser soil medium, like a collected tree mix with mostly pumice, and topdressing it with topsoil or compost. That way when you go to collect, you have more fine roots at the base of the tree and its an easier transition. This technique has worked for a dozen or so pretty large trees for me. I detail it in my field growing thread. https://www.bonsainut.com/threads/the-2024-field-growing-thread.64855/

There's some debate about the fuction of the taproot, but in mature trees I don't believe it serves any serious function. The root spread gets more nutrients for the tree than the taproot.

That’s interesting information. I’ll check your thread and do some homework before collecting. I guess, as with most things bonsai, there are different approaches. Thanks for the advice.

 

[circledisk]

I don’t think there’s any one correct way to do anything in bonsai. It’s just down to personal experience and what works for you. The nice thing is, there are millions of trees out there, so don’t worry too much about making mistakes.

 

[rockm]

There is a technique for doing in ground root pruning, but cutting the taproot should absolutely be left for last. If the tree has really expansive, thick roots, you can encourage fine root growth at the right time of year by digging a channel around the tree and filling it with a looser soil medium, like a collected tree mix with mostly pumice, and topdressing it with topsoil or compost. That way when you go to collect, you have more fine roots at the base of the tree and its an easier transition. This technique has worked for a dozen or so pretty large trees for me. I detail it in my field growing thread. https://www.bonsainut.com/threads/the-2024-field-growing-thread.64855/

There's some debate about the fuction of the taproot, but in mature trees I don't believe it serves any serious function. The root spread gets more nutrients for the tree than the taproot.

Wild growing trees and field growing collected trees isn't the same. What applies to one, doesn't necessarily apply to the other. For wild trees, a lot can depend on location, soils and species.

While pre cutting roots CAN work in some circumstances for wild growing trees, the results are spotty and sometimes fatal. It simply doesn't buy you anything over just chopping all roots at collection. I've tried it on hornbeam, wild cherry, beech, etc. in a forest environment, or in situations where the tree was among others close by. The result was that the tree that had only partial root work done weakened and slowed. That slow down allowed competing trees close by to overgrow or outgrow it. Left in place for a year, man of the trees lost top growth or significant portions of their trunk. And FWIW, a lot of trees are extremely reluctant to cross over into very different soils with their roots. Backfilling a trench with such different soil is a crap shoot at best and might be useless.

Some more vigorous trees, like the black cherry grew very aggressively after some in ground root work and managed to at least keep up with surrounding trees/vines etc.--that's because they're "pioneer" species used to growing in iffy and marginal areas in less than ideal conditions.

I would be very cautious in severing roots and leaving a wild tree to its own fate with a compromised root system. If you can get back to the site (daily, or as much as possible) to insure it is getting adequate moisture and isn't being over topped by neighboring trees or undergrowth, might be worth it. If not, there's really no reason to do any root work prior to collection for most deciduous trees.

The short of it is, in the wild, trees are competing with each other to survive. In the field, you're providing. If wild trees lose resources (and roots are extremely valuable resources) they fall behind their competitors. Falling behind is not a good thing in the wild. It can be the first step in decline.

 

[circledisk]

I think it depends heavily on the condition of the soil, the stage in the lifecycle of the forest, and the location. Wild growing is easier if the forest is more mature and the tree is at the edge where it will have less competition. I’ve had 0 failures so far keeping those factors in mind. Also, the soil shock is a moot point in my experience, you’re already doing the same thing when the tree goes in a container. It’s not like any of us are using native soil for our trees…