Forests are dynamic ecosystems and are rarely in equilibrium. This is due to natural and anthropogenic disturbances. Harvesting constitutes one of the major anthropogenic disturbances. Regeneration is a crucial component of stand development cycle and constitutes the most important phase when exploring management options and silvicultural alternatives. The primary objective of this work is to develop a natural regeneration model for PrognosisBC. The specific objectives are to validate the regeneration model using data from the moist wet Interior Cedar-Hemlock (ICHmw2) subzone variant in the Nelson vicinity and other sources of data, and to select and evaluate the choice of predictor variables. The most similar neighbour (MSN) approach was used to predict regeneration for Interior Cedar Hemlock (ICH), Interior Douglas-fir (IDF), and Montane Spruce (MS) biogeoclimatic ecosystem classification (BEC) zones in south-eastern and central of British Columbia. Data used in this analysis were previously collected from the dry cool MS (MSdk), the very dry mild IDF (IDFxm), the ICHmw2, dry cool IDF (IDFdk1, IDFdk1, IDFdk2, IDFdk3, and IDFdk4), and the dry mild IDF (IDFdm2) subzone variants. Data collected from 122, 350, and 556 plots for the MS, ICH, and IDF zones, respectively were used in this study. About 20 % of sampling was carried out on undisturbed and clear-cut sites and the remaining 80% on harvest sites with different retention levels. The plots provide different ranges of residual basal area, number of residual trees, and site factors such as aspect, elevation, geographic locations, and site series. Descriptive analyses indicate that regeneration was highly variable within the study areas and that species composition reflected pre-harvested conditions. Averages regeneration of 9141, 6559, and 2238 stems per ha were found on the sites of the ICH, MS, and IDF respectively. Zonal sites had the highest natural regeneration densities. Within each zone, the MSN made use of the plots that have both regeneration and site and overstory information (called reference plots) to predict regeneration of the plots that have site and overstory information but assumingly lack regeneration information (called target plots) by selecting the most similar plot. The performance of the four MSN models used to predict regeneration of three shade tolerant species groups by four height classes was comparable. However, the predictions of the MSN model that included the aspect as a class variable among its set of auxiliary variables were superior.
Abdel Azim, Zumrawi, Badre Tameme Hassani.
Hassani, Badre Tameme, LeMay, Valerie M.; Zumrawi, Abdel-Azim; Robinson, Donald C.E.. 2004. Implementing a PrognosisBC regeneration submodel for the complex stands of south-eastern and central British Columbia. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report