Whats going on with this Pine?

[JeffS73]

I repotted this pre-bonsai a bit early (early March) and it's been in the cold greenhouse since.

Yesterday, it suddenly looked like this:





My gut feeling is frost damage. We've had a week of cold nights and it is nearest the door, though I've been pretty good about keeping that closed at night.

Damage is all on the side nearest the door / outside.

Thoughts please?

 

[0soyoung]

Are you sure that you don't have a yellow needled variety, like a Chief Joseph, Louis, dragon's eye, etc.?

At any rate, sub-alpine species protect the photosynthetic apparatus from damage in the cold by loading up on xanthophylls, making the needles turn yellow(ish) in winter. Some varieties of conifers occur with high levels of xanthophylls and they turn yellow in bright sun exposure - in shade the foliage stays solidly green. Your tree's foliage turned yellow on the sun exposed side. Hence my question about it being one of these varieties.

 

[JeffS73]

Its a local forestry tree, I think lodgepole or pinus nigra. I know JBP and JRP go purple in the cold, but yellow looks like chlorosis or death...

I'm wondering if the roots on the exposed side froze, it's very much just up one side.

 

[Wires_Guy_wires]

I think it's root damage that's showing up. Usually that takes a couple weeks before it shows, so putting 1+1=2 is kind of an easy thing to do. Since it's just one side, the side where it's closest to the pot wall, I think it's a logical explanation.

These fabric pots are cool if they're never moved. Move them once and you basically repot the entire tree because of the movement of the soil. Be careful with those things! They do produce some of the best roots available, but one wrong move and.. Well, no more roots. I have put mine in a crate, so I can move the crate around without touching the container.