▁on ▁a ▁series ▁of ▁major ▁studies ▁of ▁ind igen ous ▁knowledge ▁and ▁of ▁the ▁consequences ▁of ▁def or est ation ▁in ▁parts ▁of ▁Indones ia ▁and ▁in ▁Br une i . ▁ ▁He ▁has ▁also ▁contributed ▁not ably ▁to ▁work ▁on ▁anth rop ological ▁history ▁and ▁method ." ▁ ▁Primary ▁research ▁area ▁ ▁Roy ▁Ellen ▁has ▁been ▁carrying ▁out ▁eth n obi ological ▁field work ▁in ▁eastern ▁Indones ia ▁since ▁the ▁early ▁ 1 9 7 0 s , ▁working ▁various ly ▁with ▁the ▁ ▁N ua ulu ▁people ▁of ▁Ser am ▁( with ▁whom ▁he ▁did ▁his ▁doctor al ▁dis sert ation ); ▁on ▁the ▁islands ▁of ▁Sul aw esi , ▁Gor om , ▁Ser am ▁La ut , ▁Band a ▁and ▁Am bon - Le ase ; ▁plus ▁some ▁addition ▁field work ▁into ▁the ▁social ▁impact s ▁of ▁logging ▁at ▁Br une i ▁( 1 9 9 1 – 1 9 9 4 ). ▁ ▁Early ▁Publishing ▁ ▁Roy ▁Ellen ▁tack led ▁the ▁debate ▁between ▁nature ▁and ▁culture . ▁ ▁St ating ▁that ▁the ▁conception ▁of ▁nature ▁has ▁varied ▁histor ically ▁and ▁eth n ograph ically ▁and ▁as ▁a ▁result ▁has ▁become ▁cultural . ▁ ▁A ▁popular ▁environmental ▁disc ourse ▁in ▁which ▁the ▁opposition ▁is ▁drawn ▁between ▁the ▁hol istic ▁system ic ▁vision ▁of ▁what ▁is ▁viewed ▁as ▁traditional ▁or ▁trib al ▁and ▁the ▁dual ism ▁of ▁the ▁modern ▁scientific ▁Christian ▁tradition . ▁ ▁In ▁his ▁view ▁nature ▁has ▁become ▁some ▁topological ▁grid ▁div iding ▁the ▁civil ised ▁and ▁the ▁un