Annex 6. Line Sample Plot Cruise Plan of a 40- 

 Acre Tract for 10% Cruise Using 1/5-Acre 

 Plots 



-« — 10 Chains- 



Plot No. 



Plot No. 20 



Plot No. 10 



Plot No. I 



I Ch. 

 2 Ch. 



2 Ch. 

 I Ch. 



End 



Eegin 

 cornor 



Annex 8. Photo Density 



1. The recognition of photo density classes is 

 based upon the use of a crown density scale. 



2. Crown density scale: 



CROWN DENSITY SCALE 



PERCENT CROWN COVER 

 I 15840 

 FOREST SURVEY- CENTRAL STATES FOREST EXPERIMENT STATION 



3. By comparing crown cover on the aerial 

 photograph with a similar crown cover on the 

 crown density scale the relative density of the 

 stand can be measured. While the measure of 

 density is not a measure of volume, it can be as- 

 sumed that the more dense a stand the more 

 value it has. Three density classes will be recog- 

 nized as follows: 



a. Crown Class A: 70-100% of the stand 

 area covered with crowns of pine trees. 



b. Crown Class B: 40-70 % of the stand 

 area covered with crowns of pine trees. 



c. Crown Class C: 10-40% of the stand 

 area covered with crowns of pine trees. 



4. For all practical purposes, only the density 

 of the dominant merchantable portion of the 

 stand need be considered. If the dominant stand 

 is saw timber then the understory can be ig- 

 nored. 



5. Density of the pine component only will be 

 considered. The classification of the hardwood 

 stands must be done by an on-the-ground in- 

 spection of the stand. 



6. Description of Pine Timber Classes 



Classes 



Al 



A2 



A3 



PI 



P2 



P3 



Rl* 



R2* 



R3* 



Stand size 



Saw Timber. 

 Saw Timber. 

 Saw Timber. 



Pulpwood 



Pulpwood 



Pulpwood 



Reproduction 

 Reproduction 

 Reproduction 



Photo density 



Class 



% 



A 



70-100 



B 



40-70 



C 



10-40 



A 



70-100 



B 



40-70 



C 



10-40 



A 



70-100 



B 



40-70 



C 



10-40 



*Make a close look for Seed Trees in this area. 



7. Before attempting to employ the above 

 procedures in timber volume estimating by use 

 of aerial photos, the following general outline 

 of work is necessary to insure a high degree of 

 accuracy. 



a. Make an intensive field reconnaissance 

 of the forest survey area. Record on 

 photos the various forest types and for- 

 est sites observed and other information 

 that might facilitate photo interpreta- 

 tion. 



b. Obtain accuracy information on a suf- 

 ficient number of randomly selected for- 

 est plots within each forest type and 

 site to yield data not determinable from 

 photos. 



c. Simultaneously with paragraph "b" 

 above obtain data to prepare local tree 

 volume tables and measurements for es- 

 tablishment of conversion factors to be 

 used in photo interpretation. 



d. Summarize data collected. 



e. Interpret photos to classify every acre 

 of land. 



8. All forest land in the survey unit should 

 be classified according to forest type and site 

 and gross timber volume estimated for each. In 

 order to accomplish this the obvious land use 

 classifications should be delineated first. The 

 following items are considered in order. 



