2011-03-24_REPORT - C1981019 (10)

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2.2.2 EP039 tFu ig is comprisea or 4.1 acres or moaeratey sloping revegetation that has a predominately east ` aspect. This unit was seeded in 2003 and therefore, +? has undergone seven growing seasons prior to I 2 3 sampling in 2010. A total of 25 plant taxa were - "? observed in the unit (Table AB-1). Current annual , production across the unit averaged 1,989.9 pounds ! per acre in 2010 with perennial grasses and perennial tt Sig ' J forbs the dominant categories (Table 1 and Chart 2). ,f Ground cover in EP039 consisted of 49.1% live r + sal' vegetation, 0.4% rock, 43.3% litter, and bare soil ,J 14 exposure of 7.3%. Perennial cover across the unit /,! averaged 33.3% with annual and biennial cover ! 15 ,a1 averaging 15.8% cover. Dominant taxa were thickspike wheatgrass, cheatgrass, and streambank 4 4" 4- wheatgrass, with 15.9%, 10.1%, and 5.6% average cover, respectively. Sub-dominant taxa include Japanese brome (Bromus japonicus), Siberian wheatgrass, and bluebunch wheatgrass (Agropyron .CYY8.M2' ftsz?7Sh74.,L14NiG11.(!R x C'ven caiaV.IW Mnt spicatum) with 2.8%, 2.6% and 2.4% cover, E?39 {= ?M respectively. Woody plant density was determined from 20 belt transects. Density (Table 3) totaled zero young and mature stems per acre. With regard to diversity, EP039 exhibited five perennial grasses with between 3% and 50% relative cover and relative forb cover of 9.2% (excluding noxious weeds). This unit readily passes the production bond release criterion, but fails the cover comparison (Charts 1 and 2). Unit EP039 currently passes the bond release diversity standard set forth by TR-72 (Charts 3 and 4). Qualified shrub acres need to be delineated, but given that there were zero shrubs per acre identified in the woody plant density belts, expectations are that this unit will need to be grouped with adjacent units to meet the woody plant density standard of 150 stems per acre on 3% of the reclaimed land. Shrub patch delineations and evaluations are slated for spring 2011. Noxious weeds appear to be controlled in this unit. There were a few sporadic Canada thistles observed in the unit, but they comprise less than 0.1% of total cover. Annual bromes are present with a total cover of 10.3%, but are down compared to 37.1% in 2007. The use of the herbicide Plateau could still be considered in this unit to further reduce competition from annual bromes and improve perennial species cover. Unit EP039 exhibits good production and moderate diversity for seven-year old revegetation. However, the cover values exhibited by this unit should be considered below average. Indications are that this unit is still on an appropriate trajectory for bond release, but additional time is required. If future monitoring reveals expansion of annual species, chemical control may recommended. Overall, Unit EP039 should be monitored again in 2013, but solutions for meeting the shrub standard need to be discussed. Cedar Creek Associates, Inc. 14 Colowyo Mine 2010 Revegetation Monitoring Report