IMHO plantáž sounds strange, we mostly associate plantáž with slaves and cotton (cocoa, tea, coffee, tobacco, ...). An arboretum is rather a kind of botanical garden. I should say:
borovicové/borové arboretum (= pine arboretum);
arboretum jehličnanů (= arboretum of coniferous trees);
borový/sosnový háj (= pine grove);
also bor (= pine grove);
borovice or less commonly sosna = pine;
háj (= grove) is a smaller group of trees, little forest, mostly natural;
arboretum is artificial;