A question of roots

[Tieball]

I have a set of tree and root questions. I have American Elm trees growing in the ground. The trees have been reduced significantly in height and pruned to basically bare trunks. From 6' tall down to 12". The trunks are about 3" diameter at the soil and perhaps wider slightly below the soil. The trees are growing on top of tiles. The tree soil is earth's ground...which is a sandy soil to me. I am confident there are a lot of roots below ground and also some thicker roots. The root base is probably a 3" depth. I have read numerous times that the Elm tolerates a lot of root removal. I am just entering the West Michigan Spring. I can easily protect the stumps should there be a frost...which can happen well into May. With this background in mind....

1. Is this a good time, even though they have just been reduced in height, to also dig them up and cut the roots back significantly?...my plan is to then put the trees back in the ground.

2. If yes to digging and root pruning now.....How do I know when to dig? Do I wait for buds to develop on the trunks? Do I wait for leaves or new small branches on the trunks to start?

3. Do I wait and dig them up next year and hard prune the roots when it is not a top growth reduction pruning year?

 

[DougB]

You have not said how long they have been in the ground or if they have budded out since the chop.

ps originally from Grand Haven and see y'all still have snow. I'm enjoying my 70's. Just wait spring will come one day and the next it will be summer.

 

[Tieball]

Buds were just starting to appear before the chop. The trees are ground growing...been on tiles for 5 years. Every other year I dig a perimeter around the tiles but don't pull the trees out. This year my intention was to pull them out after the chop and prune back the roots. I did some root pruning this afternoon. There are 10 trees. I dug up 4 and pruned them back considerably....but probably left to much root yet. I was unsure of the timing and the impact of the chop so left a fair amount of roots. The trees went back in the ground. I shortened back the roots to about a 12" circle with the tree in the middle of that circle. The other 6 trees I just did the perimeter dig again....I think I was running out of steam. There's a lot of healthy rooting under each tree. A person I talked to separately, he is in Australia, said he chops and root prunes at the same time....so I went with that direction...although I did not root prune nearly as much as he does....not even close. I think I wanted to be sure I still would get spring growth. I'll know in a couple of weeks....something will happen with the trees...or not.

 

[M. Frary]

If you chopped then as the buds were swelling they will be fine. The aussie was right. Same as collecting. Chop and dig same time just before or as the buds are swelling. Being elms you could have cut them down to the desired height. At 3 inch diameter that's around 6 inches tall.
Just protect the roots from freezing.

 

[Tieball]

On the trees I dug up and root pruned I was very pleased with the underground roots and trunk. The 3" trunks were closer to 5" below the soil. The roots flared out nicely from all around the trunks with a nice slight downward angle. The roots connected to the trunk were only about 3/8" to 1/2" but they all looked good in comparison to the trunk. All the roots were healthy. There were also many fine roots attached to the main roots and elsewhere below the trunk. The root pad was a nice very flat 2" thickness. I anticipated having runaway large roots and no fine hairline roots. So I was nicely surprised with the excellent growth below ground.

Am I right with this thinking? I root pruned the 4 trees. I just dug around the other 6 trees but left the roots alone....did not pull the trees out. I was not sure if the trees would grow well after the root prune. From what you say I should be just fine. So, should I still go back tomorrow and pull up and root prune the other 6 trees? Your thoughts?

Overall, I think that digging around the trees every other year has kept the roots compacted and well controlled. Knowing the controlled growth below ground I tend to think it best to just let the 6 without the pull-out and root cutting stay in the ground....thinking that the 6 trees will just grow that much more this season (more than the 4 root pruned trees).