Soil (and DWM) sampling on 2014 Tanana Pilot Inventory R. Pattison (PNW FIA), H. Andersen (PNW FIA) ,A. Gray (PNW FIA), Kristen Manies (USGS), FIA (IM and DC staff) Jamie Hollingsworth – UAF State of Alaska Division of Forestry (Doug Hanson) Tetlin NWR Mike Amacher (USFS)

Field plots: Tanana Valley State Forest: ~ 72 forested plots Tetlin NWR: ~27 forested plots Total: ~99 forested plots

Protocols- All plots are sampled for soils 2014- 1 subplot/plot – forested only 2016- 3 subplots/plot – forest & non-forested Borderline plots?

Makita protocol- (Nadler and Wein 1998)

Makita protocol-

Measurements and collections 2014 collected 1-4” of mineral 2016 collected 4” of mineral Crews go to 40” to try to get to mineral soil

Measurements and collections 2014 2016

Soil C totals Soils were 47- 84% of total ecosystem C (tree, DWM and soil) White spruce/TVSF soils = 47%, black spruce /TNWR soils = 84% 56,728 (+ 4,224) thousand tons of soil C on the TVSF and TNWR

Soil C totals organic layer contained 65 -81% of soil C mineral soil (1”) contained 8 -26% of soil C, Litter and live moss contained 4 - 11% of soil C

Soil C per acre Highest soil C values in black spruce forests lowest in aspen 38% of black spruce plots on TVSF did not sample entire organic layer

Missing layer In 2014 only included a layer if the layer beneath it was in the core. E.g., in order to capture all of the organic layer the core needed to have mineral soil In 2016 – considering ways to model out missing layers- e.g., based values of a portion of a layer (bulk density and %C) and thickness values in the literature.

Organic layer composition organic layer contained 65 -81% of total soil C Dead moss : 0 - 21% of organic layer Root dominated duff- found on all forest types 9% - 100% of organic layer upper humified duff layer was not present on balsam poplar forests but accounted for 17 to 35% of the other forest types

Values are similar to other studies 2014 pilot - organic layer C 12 – 28 tons acre-1 Hollingsworth et al. (2008) black spruce forests 15 - 24 tons acre-1 Kane and Vogel (2009) 17 to 33 tons acre-1 Ping et al. 2010 organic layer contained 24- 1156 tons acre-1 (52 sites in interior Alaska dominated by black spruce across a range of topographic positions from well drained to poorly drained, sampled soils down to 39”

Thaw depths Thaw depths taken at 4 points near soil sampling location Sampled to 39” (1m), recorded what is at the bottom (frozen soil, rock, not reached) Thaw depths were deepest in the balsam poplar and aspen forest types and shallowest in black spruce forests.

Thaw depth and date Frozen soils (above mineral ) were encountered throughout the growing season, not just early on.

Results Of the 99 field plots – soil samples were collected on 78 plots. Frozen soils within 1 m Black spruce - 47 of the 49 plots. Depth of the frozen soils was 40 + 3 cm. White spruce - 9 of the 14 plots. Depth of the frozen soils was 51 + 7cm Paper birch - 22 of the 25 plots. Depth of the frozen soils was 43 + 5 cm. Maybe highlight that if you cant get to mineral soil because of frozen soils you may have issues with knowing how much deeper the mineral soil is, or being able to know the extent of the organic layer. Note that we are moving to collecting in 4” units, if you can get 4” collect it.

DWM Coarse woody debris > 3” diameter, > 6” in length Fine woody debris < 3” in diameter Litter and duff depth taken at the end of each transect -

Future directions Refine insights based on veg and ground cover, community composition and soil C Develop linkages with remotely sensed data- Integrate soil data with fire studies e.g., Alonzo et al. (in review) examined ground layer burning on Kenai using lidar data as validated by FIA DWM litter and duff data. Maybe highlight that if you cant get to mineral soil because of frozen soils you may have issues with knowing how much deeper the mineral soil is, or being able to know the extent of the organic layer. Note that we are moving to collecting in 4” units, if you can get 4” collect it.