Analysis Unit Definitions. Analysis units (AUs) are aggregates of stands of similar characteristics and growth and yield responses. In order to precisely capture the value from each stand it is important to keep as much stand level information as possible, which in turn means that there is less opportunity for aggregation. For this analysis a balance was found by rounding certain stand level attributes and then aggregating in cases where the rounded attributes were identical. The rounding and classification process involved: • Rounding age to the nearest 10 years; • Rounding inventory site index to the nearest multiple of 3; • Finding the leading species; • A stands MPB characteristics: o The 2012 MPB severity rating: very severe (V), severe(S), moderate (M), low (L) or not affected; o If a stands is very severe (V) MPB affected: finding the year a stand became “very severe” MPB affected (from selected years: 2000/02/04/06/08/10/12 or never); • Harvest type: clear-cut or partial harvest (MDWR/Caribou) (the partial harvest methodology will be discussed in later sections in more detail); and • BEC zone. After this classification process, stands with the same rounded age, rounded site index, leading species, MPB characteristics, harvest type and BEC zone were grouped together in AUs. Table 19 shows a few examples AU keys. 100 18 V 2012 Pine none ESSF 100 21 V 2006 Pine mdwr_dt_M SBPSxc 100 21 V 2008 Spruce/Balsam none SBPSxc 100 6 V 2004 Spruce/Balsam none MSxv 100 6 V 2002 Douglas_fir mdwr_dt_L IDFdk3 100 6 V 2008 Pine IDFdk3 Xxxxxxx TSA TSR 4 Draft Data Package This process was used for aggregation purposes only. In other calculations, the attributes are area weight averaged for each AU which provides for a more accurate representation (for example age, site index and pine percentage). The MoFR Variable Density Yield Prediction (VDYP) model (Version 6.6d) will be used to develop natural stand yields at the AU level. A yield curve was first generated for each stand using the species composition, crown closure and site index of the stand. These yield curves were then area weight averaged to produce one yield curve for each analysis unit. Volumes were calculated net of secondary deciduous species volume contributions. The average inputs to VDYP are not presented because of the large number of natural AUs.
