Starting a new overstory before removing the old one?

I have a huge dying ash tree covering a large percentage of my back yard, and shading even more of it. I am planning to remove it in a few years, once it is all the way dead. (Even if whatever is bothering it now does not do it in, Emerald Ash borers are only 25 miles away. )

However, the question is: should I establish new trees and shrubs now, or wait till it goes? If I put them in now, they will have quite a bit of shade and root competition now, and when the tree is removed, there may be more danger of mechanical injury and a sudden shock of full sun. However, planting them now would allow them to start establishing root systems, keep unwanted competition down (because there are less resources for everyone), and poise my desired plants to capitalize on the sudden flush of water, nutrients, and sunshine made available by the eventual death and removal of the tree. Also, in this climate some shade at first might be desirable.

The plants I want to establish are hazelnuts, raspberries, and semi-dwarf fruit trees; all sun lovers. But I assume that they would grow in shade, just not produce till the tree was down.

Also, the Sun in Denver is INTENSE, which makes a big difference.

So, what would you all do?

Hi Gilbert,

I would try to take out some of the overstory on the ash, so that there is not so much shade. I live in Colorado too, and I know what you mean about the intensity of the light. Partial shade is fine for full sun plants.

I think if you get the new trees started you can count on a professional arborist to take out the old tree without hurting the new ones. One of the problems I have is that I have not left much access to the giant elms that sometimes need big pruning, so give some thought to leaving access for the arborist when you plant your new stuff.

In fact, maybe you could get a tree guy in there to do the thinning, to let the light through, and while he is there talk about the new trees you'll be planting. Not all arborists are open to clients with opinions, or clinets like me who are doing odd ball things, but some will let the owners have a say. If you have an arborist in to bid on the job of thinning the tree, you can get his opinion on the second stage of the project. Maybe some of the arborists will disqualify themselves, and one will shine as an ally in your project.

About the root competition, you could root prune the ash roots out of the areas where you are putting in the new trees.

Sometimes pruning actually stimulates growth on an ailing tree, the tree might get better not worse as a result of pruning roots and top- but that's not an educated opinion, that's just a theory I made up. See if you can get a second or third idea about possible effects of pruning on the ash before you count on it!

Where are you getting your hazels?

Thekla

Hello Thekla,

Thanks for the advice!

I'm hoping to get hazels from Badgersett. They have really cool sounding projects.

An arborist will be coming in a few weeks to clear out all dead wood and to remove a few branches that are still alive and interfering with the power wires. After he goes I will be removing a copious amount of water sprout type growth in the lower levels of the tree, since I can get at that myself, and I might thin out lower branches. Root pruning sounds OK seeing how much is being cut out of the top.

The arborist only gave us 5 years at most on it, regardless of the borers moving in from Boulder. I'll talk to him about getting some other stuff going underneath.

yes, i would plant in the shade of the dying ash tree. think of the ash tree as a nurse plant that shades and keeps the new plants cool until they can stretch their roots.

you could even trim some of the ash to strategically allow a bit more light in.


we are also loosing ash trees down along the southern frontrange  I have already started planting trees next to them as i know they wont live much longer.

My strategy has been to get my small trees in and get their roots established before exposing them to full sun. It's been so dry here this spring that I think that's the only thing that's kept half of them alive.
Finally (middle of Aug.) we've had a few days of rain to get some moisture in the soil.
Next year I'll do some serious trimming of overstory.