iod ies el ▁is ▁on going . ▁Trans ition ing ▁fully ▁to ▁bio fu els ▁could ▁require ▁immense ▁tract s ▁of ▁land ▁if ▁traditional ▁food ▁cro ps ▁are ▁used ▁( although ▁non ▁food ▁cro ps ▁can ▁be ▁util ized ). ▁The ▁problem ▁would ▁be ▁especially ▁severe ▁for ▁nations ▁with ▁large ▁econom ies , ▁since ▁energy ▁consumption ▁scales ▁with ▁economic ▁output . ▁ ▁If ▁using ▁only ▁traditional ▁food ▁plants , ▁most ▁such ▁nations ▁do ▁not ▁have ▁sufficient ▁a rable ▁land ▁to ▁produce ▁bio f uel ▁for ▁the ▁nation ' s ▁vehicles . ▁Nations ▁with ▁smaller ▁econom ies ▁( h ence ▁less ▁energy ▁consumption ) ▁and ▁more ▁a rable ▁land ▁may ▁be ▁in ▁better ▁situations , ▁although ▁many ▁regions ▁cannot ▁afford ▁to ▁di vert ▁land ▁away ▁from ▁food ▁production . ▁ ▁For ▁third ▁world ▁countries , ▁b iod ies el ▁sources ▁that ▁use ▁marg inal ▁land ▁could ▁make ▁more ▁sense ; ▁e . g ., ▁p ong am ▁o ilt ree ▁n uts ▁grown ▁along ▁roads ▁or ▁j atro pha ▁grown ▁along ▁rail ▁lines . ▁ ▁In ▁tropical ▁regions , ▁such ▁as ▁Malays ia ▁and ▁Indones ia , ▁plants ▁that ▁produce ▁pal m ▁oil ▁are ▁being ▁plant ed ▁at ▁a ▁rapid ▁pace ▁to ▁supply ▁growing ▁b iod ies el ▁demand ▁in ▁Europe ▁and ▁other ▁mark ets . ▁Scient ists ▁have ▁shown ▁that ▁the ▁removal ▁of ▁rain for est ▁for ▁pal m ▁plant ations ▁is ▁not ▁e colog ically ▁sound ▁since ▁the ▁expansion ▁of ▁oil ▁pal m ▁plant ations ▁pos es ▁a ▁threat ▁to ▁natural ▁rain