Except you don’t know how it was stored… or how hot the fire was… or how long the fire burned… or what the heat gradient across the textile was… or if the smoke permeated and affected the textile… or if the lignin concentration was uniform prior to this… or if your small number of samples are representative… or if the accuracy of the test was sensitive enough for such small masses… or if…

That is only some of the factors related to one variable labeled “Fire”.

You can make assumptions for each statement, but those assumptions are now unmoored from actual reality. You’re making up a narrative without evidence, not doing science.