Abstract: Yellow Cedar is an ecologically, culturally, and commercially important tree species; its habitat extends 20° in latitude from Southeast Alaska to the Northern California. It is experiencing extensive decline in areas of low elevation, latitude, and drainage capacity. This decline is due largely to climate change decreasing the snowpack, resulting in root-freezing injuries. Future climate change will place even the northernmost reaches of its range in conditions conducive to mortality by the end of the 21st century, putting Yellow Cedar on a path towards extinction. As vast areas of Yellow Cedar forest experience mortality, the species is also slowly migrating north to newly suitable habitat. Its northward migration is hampered by meager dispersal capability and its niche traits which limit its competitiveness to marginal soils. The effects of Yellow Cedar's northward migration needs to be better understood to properly implement conservation strategies that can protect the longevity of the species. In particular, how does Yellow Cedar colonization alter soil conditions and forest ecosystem function? Soil biogeochemical analyses in pioneer stands indicate that the presence of Yellow Cedar improves the suitability of soils to many forest species; soils have higher N content and are less acidic. The results also illuminate a decrease in the bioavailability of soil carbon with the presence of Yellow Cedar, which suggests that the species increases carbon storage capacity of soils in temperate rainforests. This suggests an increase in soil respiration in areas of decline, a positive feedback cycle from global warming. Yellow Cedar is an important case study of the global impacts of climate change on our biosphere and a harbinger for many species as climate change intensifies.