Brown Locs

The main cause of this is the sun dyeing your locs. As your locs mature, the older locs are exposed to more time in the sun. Thus, you'll see that the ends of the hair will be lighter than the hair closest to the root. I found for myself, that it became more apparent after three years of having locs.

Do dreads change color over time?

The sun. The sun is so powerful that the UVA and UVB rays cause discoloration to the hair stands by destroying the melanin. This causes a permanent change in hair color and texture. Sun bleaching is not unique to dreads but is definitely more noticeable since the same hairs are always facing the sun.

Why does hair color change from black to brown?

UVB and UVA rays are the biggest reasons why black hair turns brown. If your locks are constantly exposed to sunlight, it will cause decolourization in the melanin elements and make the hair strands appear brown. Like you would apply sunscreen on your skin, do the same for your hair.