Asayansi pa US Forest Service's Pacific Northwest Research Station Portland, Oregon, apanga chitsanzo cholosera kuphulika kwa masamba. Anagwiritsa ntchito Douglas firs muzoyesera zawo komanso adafufuza kafukufuku wa zamoyo zina za 100, kotero akuyembekeza kuti athe kusintha chitsanzo cha zomera ndi mitengo ina.
Kutentha kozizira komanso kotentha kumakhudza nthawi, ndipo kuphatikiza kosiyanasiyana kumabweretsa zotulukapo zosiyanasiyana - osati mwanzeru nthawi zonse. Ndi kutentha kwa maola ambiri, mitengo imafuna maola ochepa ofunda kuti iphulike. Chifukwa chake, kutentha kwa masika kumatha kuyambitsa kuphulika koyambirira. Koma ngati mtengo suli wozizira mokwanira, umafunika kutentha kwambiri kuti uphulike. Chifukwa chake pakusintha kwanyengo kwamphamvu kwambiri, nyengo yotentha imatha kutanthauza kuphulika kwamtsogolo.
Majini amaseweranso mpukutu, nawonso. Ofufuzawo anayesa Douglas firs kuchokera kudera la Oregon, Washington, ndi California. Mitengo yochokera kumadera ozizira kapena owuma kwambiri idawonekera kale. Mitengo yotsika kuchokera m'mizere imeneyo imatha kuchita bwino m'malo omwe azisuweni awo ofunda ndi ofunda amakhala pano.
Gululi, lotsogozedwa ndi katswiri wofufuza kafukufuku Connie Harrington, akuyembekeza kugwiritsa ntchito chitsanzochi kulosera momwe mitengo ingayankhire pazolinga zosiyanasiyana za nyengo. Ndi chidziwitso chimenecho, oyang'anira malo amatha kusankha komwe angabzale ndi zomwe angabzale, ndipo, ngati kuli kofunikira, kukonza njira zothandizira kusamuka.