Warning, shed roof felt.

This might be presumptuous that nobody has come across this, but I will explain. Last week I decided to re-felt the garden shed and in doing so I cut two pieces of green shed felt and left them on the grass for approx. 4 hrs with the rest of the roll and then finished the job. The next day 2 images appeared on the grass of the cut pieces of felt and another thin strip where the roll was laying.
It seems to be killing the grass even though I am watering the patches every evening.
It cant be what is on one side of the felt, (inside) because the roll was laying with the outside (greenside) on the grass. I suppose at worst I will have to cut these pieces out and lay some new turf in, but I'd hate to see this happen to someone with an immaculate lawn.
regards Chris

 

Some years ago I was finding about 2ft square pieces of roofing felt scattered all over the park.
I thought it was just litter, but turned out to be some local wildlife group doing a count of certain creatures, mostly slow worms and the like.
Cold blooded stuff, the idea was they would crawl under on cool but sunny days and warm themselves up, or just hide there.

My neighbours had new windows fitted and the nice fitting people scattered all the new windows, complete with wrapping all over their grass, they had some very interesting burnt areas a few days later.

 

We had that on a local SSSI the other year, also some tubular shelters fastened the bushes and trees.

 

Thank you all, I will expect to replace with new turfs later on I; the year

 

I was told that the tubular things in the trees were for detecting dormice.