INTRODUCTION 



Many stands of Rocky Mountain lodgepole pine {Pinus aontovta Dougl.) bear an abun- 

 dance of serotinous cones containing viable seed. These unopened cones remain on the 

 trees up to 40 years and may provide most of the seed for regenerating burned or logged 

 areas. However, the number of serotinous cones differs considerably from tree to tree 

 within stands; also, the same is true for the proportion of closed-cone-type trees 

 between stands (Crossley 1956; Lotan 1967, 1968). 



When the closed-cone habit prevails, the species has the ability to store seed 

 from year to year, accumulating literally millions of seed per acre, and if the forest 

 manager is aware of the seed potential, he can secure natural regeneration through 

 appropriate scheduling of cultural treatments. 



It is equally important that the forest manager recognize a lack of stored seed in 

 areas to be clearcut so that he can plan for artificial regeneration well in advance of 

 cutting. Seed dispersed annually from surrounding uncut stands cannot be expected to 

 reach more than 200 feet into cutover areas (Boe 1956, Tackle 1964). 



It is clear that in lodgepole pine management there is need for evaluation of seed 

 potential for both ecological and silvicultural purposes. The first step is to estimate 

 the biotic potential for restocking, using an estimate of the number of viable seed per 

 acre (as shown in this paper) as a base. 



Previously, Lotan (1963) published a simple linear formula using a 25-limb count of 

 serotinous cones on felled sample trees as the basis for estimating the total number of 

 serotinous cones per tree. Since then, these data have been supplemented and more de- 

 pendable multivariable formulas have been developed for use in the application of two 

 estimating methods, one involving measurements on felled trees and the other on standing 

 trees . 



ESTIMATING THE NUMBER OF VIABLE SEED 

 FOR THE AREA OF INTEREST 



This process is described below in three steps. 



A. Number of Serotinous Cones Per Acre 

 Method 1 



The first method for estimating the number of serotinous cones is likely to be the 

 most dependable of the two considered here, but is costly to apply because of the need 

 to fell plot trees. This method would perhaps be most appropriate for research appli- 

 cations in the area from which the study data originated and where higher estimating 

 precision is required. It includes use of an equation (shown below) to estimate number 

 of cones per tree for trees on sample plots. Plot totals are then converted to per- 

 acre values and are averaged. 



1 



