Some years ago there was light integration Nature with TinkersConstruct - 3or4 Flamestrings (loot from Nature spiders) was used for create TC bowstring with 1.2x durability.
Can you get it back? It will be great.
Thanx anyway

Natura adds these spiders, named "Heatscar". By default, they are disabled in the Natura config file and need to be enabled for that specific string to be dropped. They can then be crafted with tinkers construct with a wood cast.