Growing space is important. How much room should the different 

 species have nt different ages? A few figures are given for reference: 



1) Pine ) -t 20 yrs. 2 yds.sq. or 6 ft. sq. 

 Beech) Site I : 40 3 9 



Maple 60 4 "12 



80 5 " 15 



100 6 " 18 



120 7 "21 



160 8 * 24 



200 9 " 27 



2) Spruce) 



Balsam) 2 5$ less than above. 



3) Oak: 25;" more than above, especially after 60 years. 



These figures should be helpful to give some idea. They ^ are 

 er.sy to remember in sequence, if the run of the figures be noticed, 



k. The stand forms a cover on the land. Is it fully or parti- 

 ally stocked and "/hat is its expression? A crown cover is shading. It 

 may be one- storied, two or more storied, or it may form an irregular 

 canopy. This differs for pine and spruce. The spruce has a better and 

 more perfect cro^Ti cover than pine. 



The -crown cover must be estimated; it can not be measured. A 

 convenient standard of estimate should be used. 



I. Best way: In order to arrive at definite measurements we 

 commonly employ the sum of the area of the cross- sections of trees. 

 Caliper the* tress and get their areas (in cross-section). Assume such 

 a figure as 200 ft.; perhaps a good fully stocked stand should have 220 

 ffet." This gives us a means of comparison: Europeans divide this by 

 the n.rea of an acre, 43000 feet, say. Then: 



Sft. - -3L - , 2.15^, ratio of sum of areas and land. 

 43000 22p 



This ratio ordinarily ought to vary between 0.15$ and 0.50$, as 

 trees grow larger in area as they grow older. 



Another European method is the use of the distance factor. This 

 is a different point of view. As before, calipering gives the average 

 CL i n .m 6 1 G r s t 



185 trees per A at 20" ave. diam. gives 1.6 ft. 





SQ.QQ.S no. of sq.yds. per tree, gives distance between them; ab- 

 out 25 sq. yds. or 5 yds.sq. Call this "e" a 15 ft. 



, AS.,., m o.9ft. or over, which is the distance factor. 

 d i am . 1 o 



The following table shows how this works: 

 Beech (an actual case): 



Age in yrs. 

 Ave, cross-sec . 

 pj stance factor. 



TJcT": So : 100 : 120 : 

 100 : 120 : 140 : 160 : sq.ft. 

 17.5 16 : 14. 14--declines. 



If a stand at 80 years had a distance factor of 23, it was under 

 stocked, as may readily be perceived from this table. Thus the distance 

 factor gives a clue as to the condition of the stand. 



