I have recently moved into a house and have started noticing light discoloration across some wooden floor planks. I'm not sure if I'm imagining it but it seems to be spreading over the past few weeks. Is this something to worry about and does it need fixing? what could be causing it or is it natural?

Pics can be seen at https://goo.gl/photos/s83AZKNdQ2u6iBAf8

Any suggestions/help? I'm sure this is spreading. It does seem to be spreading along one vertical line. Can it have anything to do with pipes running underneath? Can hot water pipes cause this sort of discoloration?

You may be noticing the reflection from medullary rays that are a characteristic of quarter sawn oak. I have had clients that questioned whether this was insect damage. Red oak flooring has diminished "flakes" compared to the white oak.

Thanks Pete. However how does explain it spreading? I've noticed in two other area of my house where there isn't much light.

As long as I have nothing to panic about I'm fine. Just want to make sure if there is something I need to be doing I'd better do it soon

The color difference will diminish with age as the finish ambers and the effect of light makes the floor more yellow/golden colored.