Heights of planted trees are calculated using equations developed for 

 heights of subsequent trees. Age of planted trees is the number of years 

 from planting to the end of the Prognosis Model cycle plus the age of the 

 tree when planted. 



Best trees are chosen from those that are established on the plot using the 

 rules described in the section on field procedures. Best trees are assigned a 

 lower priority for removal in thinning operations simulated by the Prognosis 

 Model (see Wykofif and others 1982, pp. 16-17). Excess trees have a higher 

 priority for removal. 



Planted trees are included in the selection of best trees. Planted trees could 

 be taller than natural regeneration of the same species; however, delays in 

 planting could result in the natural regeneration being taller than planted 

 trees, so planted trees are not always chosen as best trees. 



Step 11: This is primarily a bookkeeping step for the purpose of later printing the 



Accumulate Stand regeneration summary. Predictions by plot are stored for averaging that 

 Statistics produces stand statistics. 



Step 12: Pass Tree Tree records are created during this step. Tree records created by the re- 

 Records generation model are added to the Prognosis Model tree list. This step uses 



both the probability of stocking and the results of stocked plot predictions to 

 assign a "trees-per-acre" value to new tree records. The trees-per-acre value 

 assigned to each tree record is 



TPA = (PS * TPSP * 300)/Ar (4) 



where 



TPA = trees per acre 

 PS = plot probability of stocking 

 TPSP = trees per stocked plot 

 300 = inverse of plot size used in sampling 



= number of plots and replicates being processed. 



Each best tree on the plot becomes a separate tree record, so TPSP is 1.0 

 for best trees. Excess trees are accumulated by species, then tree records 

 are created so that TPSP is <5 trees. 



The value of PS for planted trees is not the probability of stocking; rather, 

 it is the density of planting specified by the user. Usually one tree record 

 for each species being planted is created for each plot. Multiple records are 

 created when high densities are planted (a tree record represents >10 trees 

 per acre). 



A regeneration summary is printed each time the regeneration model is 

 invoked. The first tally in a tally sequence includes a heading that shows 

 the stand identification, site preparation by year performed, and number of 

 plots by habitat type group. 



Each tally shows the cumulative probability of stocking and three summaries 

 of regeneration by species. The first summary is for all trees regenerating 

 during the cycle. This summary is similar to a conventional stand exam. The 

 second summary lists best trees regenerating during the cycle. Densities 

 and average heights are listed by species for best trees. Focusing on best 

 trees gives a more realistic picture of potential crop trees in the stand. For 

 example, one could determine the number of Douglas-fir that could be favored 

 in the stand through a thinning operation. 



Step 10: Identify 

 Best Trees 



Step 13: Print 

 Regeneration 

 Summary 



28 



