At Toolik Lake, between the reciprocal transplant gardens and the access road and at the Anaktuvik severe burn site 20 m east of the eddy flux town root and mycorrhizal exclusion experiments were established. 10 cm wide, 13cm long PVC collars had 4 x 5 cm holes cut into the side, 4 cm from the base. The holes and the base were wither covered with either a 2 mm plastic mesh or a ...um nylon mesh.

Organic soil from either the Anaktuvik severe burn or Toolik Lake was taken back to the lab, dried and put through a 4mm seive to remove large roots and stones. The cores were filled to 11 cm height with 138g of soil, resulting in a bulk density of 0.132 g/cm3.

Cores were established in the field on ... at Toolik and on ... at the burn. At each site, 5 blocks were established approximately 10 m apart. A block consisted of a patch of shrubs 9m2 in area. 3 cores were inserted into each shrub patch, 2 with the nylon mesh, one with the 2 mm plastic mesh. This was done by cutting a 8 cm wide hole to 11 cm depth so that the core fit very tightly with 2 cm visable above the soil.  Approximately every 7 days one of the nylon cores (always the same one) was rotated by 30 ° in order to sever any in-grown mycorrhizal fungi, this was labeled with red tape and flagging in the field and called the 'H' treatment for 'heterotrophs only'. One of the nylon-mesh cores  was left static to allow mycorrhizal ('MH' treatment) ingrowth and labeled with blue tape and flagging. The cores with 2 mm plastic mesh covering the holes allowed roots and mycorrhizae into the soil ('RMH' treatment)  and labeled with yellow tape and flagging.

A licor 6400 with 6400-09 soil respiration chamber was used to measure soil respiration (efflux) from the cores on a weekly basis. The red 'rotated' cores were rotated AFTER the flux measurement.