Investigation of vertical root distributions in a sparse conifer forest underlain by permafrost in interior Alaska
Overseas Fellowship Program Participant:FY2024 Short-Term Program
Gaku Amada (Forestry and Forest Products Research Institute)
I stayed at the University of Alaska, Fairbanks (UAF) from August 26th to September 25th, which was supported by short-term Overseas Fellowship Program of ArCSII. During this stay, in order to clarify mechanisms of vegetation responses to permafrost degradation, I investigated vertical distributions of fine roots (diameter<2 mm) in a black-spruce forest underlain by permafrost. Permafrost degradation occur in circumpolar regions have that are rapidly warming. Recent studies suggest that plants spreading their roots to deeper soil layers can sensitively respond to permafrost thawing. However, there few studies that examine the vertical fine-root distributions of permafrost vegetations because it is so difficult to identify species of fine roots. Thus, in this program, I conducted vertical root samplings in a typical black-spruce forest underlain by permafrost in interior Alaska.

Study sites was established in the Poker Flat Research Range (PFRR) of the University of Alaska, Fairbanks. In the PFRR, UAF and JAMSTEC researchers investigates permafrost conditions. Ten small quadrats were established there, and soil cores were collected at every 10-cm depth. I brought the cores to the UAF laboratory and divided them to three soil samples: ① samples for species identification, ② samples for root biomass measurements, and ③ samples for soil nutrient analyses. In ① and ②, I carefully sorted fine roots from the soil samples (136 samples) with tweezers. This is so hard because It took me 2-3 hours to sort each sample. Then, I handed over the root samples of ② to Diana Wolf and Naoki Takebayashi who are specialist for the genetic analysis. I brought ③ soil samples back to Japan and am conducting soil nutrient analyses in Japan.

I sincerely appreciate the ArCS II research gland. With this financial support, I was able to complete my fieldwork in Alaska.