There is a well-known phrase associated with Sherlock Holmes: "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."
Today, along Reebokweg, I came across scattered tufts of fine black fur. There was no obvious kill nearby nor remains of one.
The colour and texture would rule out deer, fox, boar etc. I don’t believe anyone decided to groom their dog here and domestic cats, although notorious shedders, would not be this far into the Forest.
Which leaves the notoriously bad-tempered mustelids - weasels, martens, stoats and polecats. A wolverine is out of the question, otters need water, and badgers haven’t been seen here for decades. I suspect a territorial fight between Beech Martens, 𝑀𝑎𝑟𝑡𝑒𝑠 𝑓𝑜𝑖𝑛𝑎.
Nothing else appears to fit.