▁the ▁park ▁bo asted ▁el ms ▁and ▁pop l ars ▁ 2 5 ▁meters ▁tall ▁high ▁and ▁o aks ▁with ▁ 3 0 0 ▁to ▁ 4 8 0   cm ▁circum ference ▁tr unks . ▁ ▁After ▁World ▁War ▁II ▁and ▁the ▁destruction ▁of ▁part ▁of ▁the ▁trees , ▁new ▁plant ings ▁have ▁been ▁carried ▁out ▁in ▁the ▁post - war ▁years . ▁In ▁ 1 9 5 2 , ▁during ▁the ▁construction ▁of ▁the ▁P omer an ian ▁Phil harm onic ▁hall , ▁four ▁ 4 0 0   cm - per imeter ▁o aks ▁were ▁cut ▁down . ▁In ▁ 1 9 5 8 , ▁the ▁southern ▁limit ▁of ▁the ▁park ▁has ▁been ▁extended ▁to ▁include ▁the ▁area ▁of ▁the ▁Phil harm onic . ▁In ▁ 1 9 6 0 , ▁in ▁the ▁northern ▁part ▁of ▁the ▁park , ▁the ▁statue ▁The ▁Arch er , ▁one ▁of ▁By dg osz cz ▁icons , ▁was ▁installed ▁to ▁a ▁dedicated ▁rect angular ▁square . ▁ ▁In ▁ 2 0 1 4 , ▁an ▁over ha ul ▁of ▁Jan ▁Koch an owski ▁Park ▁has ▁been ▁performed , ▁to ▁highlight ▁its ▁historical ▁character ▁and ▁link ▁it ▁with ▁the ▁Music ▁District . ▁This ▁works ▁included : ▁ ▁Rem oving ▁as ph alt ▁alle ys ▁from ▁the ▁ 1 9 6 0 s ; ▁ ▁New ▁species ▁( D oug las ▁f irs , ▁ber ber is , ▁Sea ▁bu ck th orn , ▁ly che e ▁tree ) ▁were ▁introduced ▁as ▁in ▁Kon rad ▁Ne