▁for ests ▁travers able . ▁Another ▁human ▁use ▁for ▁fire ▁in ▁regards ▁to ▁landscape ▁management ▁is ▁its ▁use ▁to ▁clear ▁land ▁for ▁agricult ure . ▁Sl ash - and - burn ▁agricult ure ▁is ▁still ▁common ▁across ▁much ▁of ▁tropical ▁Africa , ▁Asia ▁and ▁South ▁America . ▁" For ▁small ▁far mers , ▁it ▁is ▁a ▁convenient ▁way ▁to ▁clear ▁over g rown ▁areas ▁and ▁release ▁nut ri ents ▁from ▁standing ▁veget ation ▁back ▁into ▁the ▁soil ", ▁said ▁Miguel ▁P ined o - V as quez , ▁an ▁e colog ist ▁at ▁the ▁Earth ▁Institute ’ s ▁Center ▁for ▁Environment al ▁Research ▁and ▁Conserv ation . ▁However ▁this ▁useful ▁strategy ▁is ▁also ▁problem atic . ▁G row ing ▁population , ▁fragment ation ▁of ▁for ests ▁and ▁war ming ▁climate ▁are ▁making ▁the ▁earth ' s ▁surface ▁more ▁pr one ▁to ▁ever - lar ger ▁escaped ▁fires . ▁These ▁harm ▁e cos ystem s ▁and ▁human ▁infrastr ucture , ▁cause ▁health ▁problems , ▁and ▁send ▁up ▁spir als ▁of ▁carbon ▁and ▁so ot ▁that ▁may ▁encou rage ▁even ▁more ▁war ming ▁of ▁the ▁atmosphere ▁– ▁and ▁thus ▁feed ▁back ▁into ▁more ▁fires . ▁G lob ally ▁today , ▁as ▁much ▁as ▁ 5 ▁million ▁square ▁kilometres ▁– ▁an ▁area ▁more ▁than ▁half ▁the ▁size ▁of ▁the ▁United ▁States ▁– ▁burn s ▁in ▁a ▁given ▁year . ▁ ▁There ▁are ▁numerous ▁modern ▁applications ▁of ▁fire . ▁In ▁its ▁broad est ▁sense , ▁fire ▁is ▁used ▁by ▁nearly ▁every ▁human ▁being ▁on ▁earth ▁in ▁a