▁m ast ▁and ▁their ▁trees ▁and ▁ 4 6 5 ▁p igs ▁can ▁be ▁kept ▁there "). ▁ ▁At ▁the ▁beginning ▁of ▁the ▁ 1 8 th ▁century ▁at ▁the ▁inst ig ation ▁of ▁the ▁Duke ▁of ▁St rel itz , ▁Ad olph us ▁Frederick ▁II , ▁numerous ▁glass works ▁and ▁pot ash ▁dist iller ies ▁were ▁founded ▁in ▁the ▁region , ▁but ▁the ▁Ser ra hn ▁Hills ▁remained ▁una ffect ed ▁due ▁to ▁poor ▁road ▁communic ations ▁and ▁its ▁for ests ▁remained ▁largely ▁int act . ▁This ▁made ▁it ▁a ▁popular ▁hunting ▁area ▁as ▁well ▁as ▁a ▁botan ical ▁forest ry ▁research ▁site ▁for ▁the ▁du kes ▁of ▁Me ck len burg - St rel itz . ▁ ▁In ▁G DR ▁times , ▁the ▁hills ▁were ▁designated ▁as ▁a ▁nature ▁reserve ▁and ▁became ▁well ▁known ▁as ▁the ▁centre ▁of ▁the ▁great ▁state ▁hunting ▁grounds ▁called ▁the ▁Wil hel min en hof ▁Wild life ▁Research ▁Area ▁( W ild forsch ungs gebiet ▁Wil hel min en hof ). ▁ ▁Since ▁June ▁ 2 0 1 1 , ▁the ▁be ech ▁for ests ▁of ▁the ▁Ser ra hn ▁Hills , ▁along ▁with ▁four ▁other ▁German ▁be ech ▁for ests , ▁have ▁been ▁recogn ised ▁as ▁a ▁ ▁UN ES CO ▁World ▁Heritage ▁Site . ▁They ▁are ▁the ▁last ▁remaining ▁semi - natural ▁be ech ▁for ests ▁in ▁Germany . ▁ ▁References ▁ ▁External ▁links ▁▁ ▁www . t our istik kar te . de ▁ ▁Category : H ills ▁of ▁Me ck len burg