Categories: Safety Guides FISA 503 Extraction by forwarder This leaflet covers the use of a tractor and trailer unit fitted with a grapple loader or a purpose-built forwarder for extraction of timber in forestry and other tree work. March 2018 - This Safety Guide has been ‘partially’ updated to reflect the new ‘stack heights’ guidance. 503 will be further updated to the new style towards the end of 2018. Documents to download FISA 503 Extraction by forwarder - updated March 2018.pdf(.pdf, 1.81 MB) Previous Article FISA 502 Next Article FISA 504 Print