Conventions

Several commonly accepted standards and practices used in timber harvesting were applied in order to attain more realistic results and maintain consistency of data.

• A standard coordinate system of Universal Transverse Mercator-North American Datum 1983-Zone 13 north was used.
• A grid cell size of ~25x25m (from the ASTER DEM) was used.
• For all raster outputs with cell size options, the ASTER_DEM file was selected as a template so outputs would match its spatial resolution and cell alignment.
• No cutting or management within 100 feet of a stream or water source in order to protect water quality.
• No cutting or management inside designated roadless or wilderness areas, since access would be extremely limited and use of mechanized devices inside wilderness areas is prohibited by congress.
• Standard buffer distances of 100 feet from the center of a trail, 200 feet from the center of a road and 400 feet from the center of a recreation site were used.
• Prior to 2009, there were no damage causal agents listed specifically as Sudden Aspen Decline (SAD) code 24032, but rather as the primary insect or disease contributing to the decline of the stand.  Therefore, for all years it is assumed that any damage to aspen (Host code 746) is a result of SAD.
• Mechanical treatment is defined as any commercial ground based logging operation that would include standard; ground based logging equipment such as harvesters, feller bunchers, rubber tired or tracked skidders, masticators, hydro axes, or any other related logging equipment.  For mechanical operations to occur a stand must have a mean slope of 25% or less and be accessible from a road.
• Hand treatment in this project is defined as a crew of persons equipped with chainsaws.  Hand felling and processing all trees will occur without the use of heavy logging equipment as described for mechanical treatment.  The maximum acreage of a stand to be treated by hand is 50 acres.  It is assumed that any hand treatment of a stand greater than 50 acres would be prohibitively costly and the management strategy will convert to a buffer area only.  In order for a stand to be treated by hand, the mean slope must be greater than 25% (excluding mechanical treatment) but cannot exceed 35%, and the stand must have road access.
• Buffer treatments are defined as any areas where slopes, access, or stand size would be restrictive in implementing a treatment of the entire aspen stand using either mechanical or hand treatments.  Stands where mean slope exceeds 35%, stands between 25% and 35% and 50 acres or greater in size or stands without road access will be treated according to a buffer width of 100 feet from the center line of any trail, 200 feet from the center line of any road, and 400 feet from any recreation site.
• Current vegetation cover used to determine ecological value was taken from the LANDFIRE products portal. It was assumed that current vegetation cover of Rocky Mountain Aspen (type 2011) would have higher ecological value for management than Rocky Mountain Mixed Aspen-Conifer (type 2061).
• Classification errors were assumed to exist in the current vegetation cover product since it is a classified product based on remotely-sensed Landsat imagery. We have no way of dealing with errors of commission, but we can add value to nearby cells based on distance to represent the possibility that nearby cells contain aspen, but were classified as some other forest type.
• Priority levels 1-4 were rather were subjectively determined by a rules matrix for the vector analysis, but for raster analyses represent scores ranging from 0-25 (4), 25-50 (3), 50-75 (2), and 75-100 (1).