Remeasurement 



Permanent field locations established by this inventory lend themselves to 

 remeasurement. However, several considerations should govern the reinventory design. 

 First, reinvent ories based to a large degree on repeated examination of the same sample 

 locations will perpetuate deviations about the true population total. This persistence 

 is particularly serious when the programed level of harvest is one of the population 

 totals being estimated. The feedback effect of remeasured plots in inventories for 

 harvest scheduling has not been examined thoroughly. However, there exists a definite 

 possibility that the serial correlation of sampling errors from inventory to reinventory 

 could result in persistent overcutting, undercutting, or unstable, destructive 

 oscillations that would vitiate our reliance on compensating corrections as a result 

 of successive revision of the management plan. 



The second consideration is that the availability of "in place" information will 

 play a major role in timber management program development during the execution of the 

 plan. In other words, the timber programs will tend to be concentrated in the hundreds 

 of stands already inventoried on the ground. Therefore, at the time of reinventory, 

 those subcompartments already inventoried on the ground will have to be treated as one 

 stratum, those not already inventoried on the ground as another stratum. 



In summary, the design discussed in this paper should be considered a transitional 

 design for establishing a complete timberland record based on stand examinations. 

 Subsequent inventories for the same forest should be designed to use the information 

 contained in these records so as to provide statistically sound estimates of the current 

 forest situation with greatly increased efficiency. 



Compilation 



Compilation procedures are quite similar to those used in processing typical ran- 

 dom plot inventory data, the major change being development of "stand" data rather 

 than "plot" or "location" data. The only real change in compilation procedures is to 

 replace the constant 10 for points per cluster with a variable number of points per 

 stand. Variance estimates are, of course, quite different. Variance computations 

 are described on page 15. An abbreviated flow chart is included in figure 2 to illus- 

 trate data flow and the correlation of the four major types of information- -the field 

 inventory, the photo inventory of stands, photo mortality samples, and the felled- 

 tree (net volume) data. 



The first stage of the output that is of use to the forest manager is the stand 

 analysis. These stand records are the basic material from which the management program 

 is built. In particular, growth prognoses under alternative stand treatments can be 

 used to develop a rational basis for establishing the management program. 



It should be emphasized at this point that stand or "in place" data developed by 

 field inventory in this overall system lose considerable utility unless the forest 

 manager has an information system that provides ready storage and retrieval of 

 individual stand data. 



The various stand attributes are averaged within their respective strata. These 

 stratum means are inferred to the nonsampled acres within the strata by compartments. 

 Thus, the photo classification phase of the double-sampling procedure will extend the 

 stand data to those compartments not sampled on the ground. Compartments average about 

 5,700 acres in size, so there will be about 57 photo samples in each. Compartment 

 statistics determined solely from photo stratification will fill in the gaps in the 

 inventory of the entire forest. As additional field inventory work (stand examination) 

 is completed in ensuing years, it will replace information based on only strata means. 

 The summary of these compartment records provides the final stage of the output. This 

 output consists of a series of tables that provides the base for broad scale timber 

 management planning. 



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