Black pine bark going brown?

[gusmyy]

Hi guys

I have a black pine that i recently fertilized. All of a sudden its bark in the base went kinda brown, looking like it burned. It dont think it is dirty from the substrate. Can anyone tell me what is going on?

I live in Brazil and it is autumn in here

 

[Grunge_Bonsai]

I’m not very experienced, but I think brown bark is normal.

Which section looks off color? My JBPs generally have bark within that color range.

 

[gusmyy]

I’m not very experienced, but I think brown bark is normal.

Which section looks off color? My JBPs generally have bark within that color range.

All the brown parts in the base used to be completly grey untill yesterday

 

[Grunge_Bonsai]

All the brown parts in the base used to be completly grey untill yesterday

Maybe I’m missing something, but that brown looks like a healthier color than the grey.

What substrate are you using?