Pay attention to the different types of FSC certification, which you can find on product cut sheets. You will need a letter, cut sheet, or statement from the vendor indicating the type of FSC certification.

FSC Pure: valued at 100% of product cost. 
FSC Mixed Credit: valued at 100% of product cost.
FSC Mixed (XX)%: A percentage of FSC content is indicated, and you can claim that percentage of the product’s cost. 
FSC Recycled and FSC Recycled Credit: do not count toward this credit at all and can be left out of the baseline wood budget. FSC Recycled can count towards MRc4 Recycled Content.