GENERAL32515

• Permit No: C1981010
• IBM Index Class Name: General Documents
• Doc Date: 4/14/1987
• Doc Name: MEMO PROPOSED REVEGETATION SUCCESS MEASURES
• From: MLRD
• To: GREGG SQUIRE MIKE LONG
• Permit Index Doc Type: VEGETATION
• Media Type: D
• Archive: No

• • III IIIIIIIIIIIII III
999
STATE OF COLORADO
Roy Romer, Gove
DEPARTMENT OF NATURAL RESOURCES
MINED LAND RECLAMATION DIVISION
DAVID C. SHELTON, Director
DATE: April 14, 1987
T0: Gregg Squire and Mike Long
FROM: Mike Savage /f(!~
RE: TRAPPER MINE (C-81-010) PROPOSED REVEGETATION SUCCESS MEASURES
I have completed a review of Trapper Mine's revegetation success measurement
proposal dated February 13, 1987. I have limited my review to the proposals
regarding cover and production, as my proposal regarding woody plant density
is contained in my April 25, 1986 memo to you.
Trapper Mining has proposed that the reference area concept may not be viable
due to year to year variation within reference areas and between reference
areas and pre-mine (undisturbed) areas, and cites Tables 4.4-13 and 4.4-14
included in the package. While the Division does not dispute the contention
that biotic and abiotic factors will influence the absolute values of
population parameters on a yearly basis, the information Trapper references
does not indicate variation of such a significant nature so as to render the
reference area concept invalid. When Trapper selected the reference areas for
their range sites originally, they created three separate sub-reference areas
within each range site whose purpose was to show the inherent variablility
within each range site and preclude any failure to accommodate such
intra-community variability when evaluations of revegetation success were to
occur. It was for the above reasons that the Division accepted Trapper's
multiple reference areas for each community (range site).
Trapper has proposed several methods of evaluating revegetation success within
this package. The first methods presented for cover and production propose
sampling cover and production in reclaimed areas and reference areas and
comparing the values statistically to determine revegetation success. These
methods are acceptable as presented. I would make one suggestion regarding
the cover sampling procedures proposed on page 4-102. While 20 sample points
may be sufficient to estimate cover within 5 percent, it is usually
advantageous to increase the number of points taken per transect to reduce
variability between transects as a function of the sampling method,
particularly when one is dealing with binomial data (as is the case with cover
in this instance).
Trapper has also proposed to use mathematical regression techniques to produce
a predictive mathematical equation from which a numerical value (standard) for
cover or production may be calculated on a yearly basis. The use of
predictive models and mathematical techniques to generate technical standards
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. [phone]