Post mortem diagnosis

Hi there Miraians,

unfortunatelly i lost this young forest planting which i started last year.

I still don’t really know the reason why. It lost its leaves during the last summer and never really bounced back to a good health. Now, after all trees died i made a post mortem. The soil didn’t look too wet or too dry but all the roots were dead. The amount of the roots wasn’t excessive but it definitely built up a good amount of them. The only things i found in the soil were two white, clumpy spots which were quite soft:

here’s a zoom in of this spot and how it looks when you break it up:

Like i said, i just found two spots like this in the whole pot and some traces under one trunk and on some roots:

but compared to the root mass the infected parts were quite small. I can not really understand why such a small amount of a fungus (if it is one) could have such a dramatic impact except the roots were connected so strong that the fungus could infect them inside of them.

One idea is the amount of lime inside of my water. I live in an urban area and have to use tap water which is pretty hard, unfortunately. Do you guys think this could be the simple reason?

I really hope you guys can solve the problem and help me so i will learn something from this loss.

Sorry about the long post and stay safe/stay home.

Looks to me like the soil selection. May have had something to due with the death. Akadama is everything Ryan says it is. Was it outside for the winter?

The soil is a mix of acadama, pumice, lava and a little bit of turf. I don’t think that the soil itself is the problem. I really suspect that the hardness of my water is the issue. Beech is a tree which is very sensitive to this in general and my water has a hardness of 17 °dH (German hardness) which is comparable to 330 ppm CaCO3. I just didn’t expect to really kill the trees with this.

My experience with hard water is that plants won’t die off that fast. I’ve tried to grow azaleas and have failed miserably because of the water. Anytime calcium is the problem the tree shows chlorosis.