Araucaria araucana On Winter

Why does my araucaria gets yellow on winter? On spring it was dark green color and now is full yellow. Can i save it or?

Where abouts are you and how cold are your winters? Because that looks more like a Araucaria angustifolia than an Araucana.

I live in Croatia. This winter was like -10,-15 Celsius. I don't know, it was sold to me like araucana and it looks to me like that. I don't know this species very well so that's why am i asking for a advice here.
Anyway tnx for help, i google it, possible it is Araucaria angustifolia . So what can i do to save it? Leaves are still sharps like before,it just losed color.

If its araucana, then it's probably dying. Once the leaves turn brown, it's pretty hard to bring them back. It's often from too much or too little water, although they can take both. They get drenched in water here (Chile) for a good part of the year, but they primarily grow on volcanic - i.e. well-drained - soils. Their native climate is high and cold in winter, so I doubt it's the cold.
Is angustifolia the deciduous one? I don't know that one, just the one native to southern Chile. Good luck!

Tnx. So is there way to save it? I think it has started to get light green color from top

I'm not sure. I would make sure it's got good drainage, isn't dried out, basic things like that. Good luck!

The picture you show as the new tree, with the white mulch; does not have all that amount of sticks and that huge pole and cross boards around the small tree. So I supposed you made all of that after... I think, that doing the digging for the pole, disturbed the root of the plant, and besides all those sticks are just  asfphyxiting the plant. So, regardless watering, warm and cold etc... the plant have been afflictedby its surroundings...

Hi. On spring i planted my 4-5 year old araucaria outside, and it was dark green color. When winter came, i put it on shelter by pine branches to protect it from snow and low temperatures. One month later it became yellow. What is the problem? To much cold (I live in Croatia) or it gets yellow because of no sun. I will add pictures. Thanks

Let it grow without poles or support
If its green on top it may still be alive