Why did my alder die?

[spandit]

The alder have been the champions of my new woodland, growing quickly and providing a good structure and windbreak for some of the slower growing trees. However, I noticed that this one had died:

 

 

Closer inspection showed that the trunk was mostly dead, although below about 2' it was still green. Can't see any rusty spots on the trunk:

 

 

Cut it off where it was still alive with the hope it will pollard itself but as you can see from this bit (hopefully), half the main stem is dead:

 

 

This is echoed in another one nearby:

 

 

Just one of those things or a disease that means the whole lot are going to succumb? I was hoping to preserve a piece of the first log I cut but not like this.

[Treeation]

How long ago since you planted the alder?

[Treeation]

The trunk looks like it might have blackened tarry spots on? Maybe Phytophthora

 

https://www.forestry.gov.uk/pdf/fcin6.pdf/$FILE/fcin6.pdf

[spandit]

Not convinced they are tarry spots but I'll get out tomorrow if I'm able to have a closer look. There was quite a bit of grass growing up inside the tube and air roots had formed which may account for the markings.

 

 

The alder is 4 years old now. I'll be devastated if it is phytophthora...

[Treeation]

Do you control competing weeds around the stock? if so how?

[Goaty]

A dry spell can weaken them. They need sap and constant moisture to thrive.

But it looks like phytophra to me. Its well documented. Google will soon find more info for you. Ive probably read the fc doc quoted above. It is sad news.

 

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[spandit]

So if it is phytophthora, does this mean the rest of them are going to die now? That's a depressing thought.

 

Re: weed control, I don't use chemicals, I just remove them from the tubes when the tree seems to be struggling. Because this tree was well out of the tube, I presumed that it wasn't being curtailed by weeds and it's difficult to lift the tube once the branches are forking out like that.

[Treeation]

Should really be clearing weeds to give at least 0.5m radius around each tree. Also, apply 100mm of mulch too around the cleared area, ths will help to retian moisture, supress weeds and add organic matter to soil, top up mulch when level is low

 

Every little bit helps - very importants druing establishement phase.

 

As for phytophthora, it wouldnt be good. Guess you need to get confirmation. I think you can send off sample to Forestry Commission or RHS to confirm. Coppicing alder seems to show some resistance as it says in the article I posted earlier.

[spandit]

Not practical to clear weeds and mulch around 2,000+ trees and I thought this one was properly established anyway, the leaves being able to photosynthesise as it was well clear of the tube.

 

Not sure what good confirmation would do - unless there's a way to inoculate against the disease I'm just pretty helpless.

[spandit]

Had a closer look just now - no signs of black tarry spots at all. Has big thick roots but wonder if one of the many resident moles or voles have undermined and exposed them causing them to dry out?