I Kepakemapa, ua hoʻopuka ka Pacific Northwest Research Station i kāna hōʻike "Ka helu ʻana i ka ʻōmaʻomaʻo i ka ʻōmaʻomaʻo: He aha ka waiwai o ka lāʻau Urban?". Ua hoʻopau ʻia ka noiʻi ma Sacramento, CA a me Portland, OR.
Ua hoʻoholo ʻo Geoffrey Donovan, ka mea hana nahele noiʻi me ka PNW Research Station, ʻo nā kumulāʻau i kanu ʻia ma ka ʻaoʻao hema a me ke komohana o nā hale o Sacramento i hoʻemi i nā bila uila o ke kauwela ma ka awelika o $25.16. Ma ka lua o ka noiʻi ʻana ma Portland, ua ʻike ka hui o Donovan e ulu ana nā lāʻau alanui ma mua a kokoke paha i kahi hale i hoʻohui ʻia he $8,870 awelika i kāna kumukūʻai kūʻai a hoʻemi i kona manawa ma ka mākeke ma kahi kokoke i 2 mau lā. Ua lilo kēia mau pōmaikaʻi waiwai i nā waiwai e pili ana: ua hoʻohui ʻia kahi kumulāʻau kaiāulu e ulu ana ma ka ʻaoʻao ʻākau o ka lehulehu i ka awelika o $12,828 i ka waiwai hui o nā hale a pau i loko o 100 kapuaʻi.
Hiki iā ʻoe ke heluhelu i ka haʻawina piha maanei.