Table 8 — Example projections to compare consistency of various cycle lengths using the same 

 stand. Projection A is four 5-year cycles, projection B is two 1 0-year cycles, and pro- 

 jection C is one 20-year cycle 



Projection A 



Projection B 



Stoclting 



5 yr 



10 yr 



15 yr 



20 yr 



10 yr 



20 yr 



20 yr 



Cumulative 

















probability 

















of stocking 



0.6186 



0.7380 



0.8126 



0.8669 



0.7380 



0.8631 



0.8601 



Cumulative 

















trees/acre 



582 



772 



943 



1,086 



772 



1,081 



1,076 



Cumulative 

















trees/acre 

















by species 

















1 Aim 



41 



49 



59 



74 



49 



73 



72 



L 



21 



30 



34 



37 



30 



36 



41 



DF 



157 



192 



222 



248 



193 



249 



262 



GF 



330 



462 



575 



667 



460 



667 



635 



WH 































C 































LP 



7 



8 



14 



20 



9 



9 



20 



S 



18 



22 



29 



30 



22 



36 



36 



AF 























1 







PP 



8 



9 



10 



10 



9 



10 



10 



^See table 1 for species abbreviations. 



Ingrowth Ingrowth is regeneration that occurs after the 20-year regeneration period. 



It is the continued succession by shade-tolerant species, and the regeneration 

 of trees into gaps in the overstory canopy. An ingrowth taUy of regeneration 

 is predicted every 20 years if the regeneration model has not been invoked 

 during that time, and no regeneration activities are scheduled for the next 

 Prognosis Model cycle. 



Data collected for the regeneration model did not specifically address in- 

 growth into undisturbed stands. However, the data contain many plots repre- 

 senting conditions where ingrowth occurs. These are areas with fairly dense 

 overstory canopies where no harvesting or site preparation had taken place 

 (see table 5). The systematic arrangement of transects or sampling grids in 

 selection, sanitation, or salvage harvests resulted in many of these plots being 

 included in the sample. 



When predicting ingrowth, all plots are simulated as receiving no site prepa- 

 ration. Ingrowth tree records are created and passed to the Prognosis Model. 

 An assortment of tree sizes is added to the stand because trees up to 20 years 

 old can be established. The trees then survive and grow based on tree, site, 

 and stand characteristics. 



Simulation of ingrowth creates more realistic projections of stand develop- 

 ment over time. It also allows projections that simulate succession over long 

 time periods. The Prognosis Model with the regeneration model can be used 

 in areas of forest management that require evaluation of uneven-age and 

 old-growth silviculture. 



Automatic Tallies The Prognosis Model includes a feature that invokes an automatic scheduling 



of the regeneration model when trees are removed. Thinnings scheduled by the 

 user may have opened the stand enough for regeneration to become established. 



36 



