Data from a series of plots in well stocked, even-aged Picea sitchensis/Tsuga heterophylla stands 30-170 years old (that had developed after logging (a), windblow (b) or fire (c) on various freely drained soils) were used to determine a site index based on total height and age of dominant P. sitchensis. The site index values obtained were 152 for (a) and (c), but only 126 for (b). Implications for the accuracy of enumeration surveys are briefly discussed.