138 Forestry Quarterly 



verely-thinned beech stands compared with that in dense stand 

 does not increase in proportion to the size of crown. Respira- 

 tion and transpiration stand in similar relation. Physiologically 

 the disproportion of increment and intensity of assimilation is 

 in beech the greater, the more severe the opening. This does 

 not, however, mean that severe thinnings may not produce 

 larger total increment than lighter ones. At the same time the 

 investigations furnish proof of the uselessness of removing the 

 subdominant growth which does not interfere, and accentuate 

 the desirability of thinning in the dominant. 



Relations are somewhat different with the light-needing Aus- 

 trian Pine. 



To illustrate the method of statement, we reproduce one of 

 the tables. 



AUSTRI.AN' PINE THINNING AREA NO 2. AGE 57 YEARS. 



Light Medium Severe 



Thinning Thinning Thinning 



Number of trees iti 1902 8296 6071 3476 



Volumt- per tree, in 1902, m* .028 .038 05S 



Light intensity May 3, 1902 17 .23 31 



Light absorhed ; per cent, of light in open. S3 77 69 



Shade coefficient, 100 i 1.3 2 



n 



Compared with beech the smaller numerical difference of 

 crown density is striking ; the shade coefficients for beech of 

 nearly the same age (63) having been found as 4.4, 7.9, 10.7, as 

 against i, 1.3, 2. 



In another pine stand the increments of differently thinned 

 areas were as r : 1.4 : 1.7 : 2.2, while the shade coefficients 

 were as i : 1.3 : 1.6 : 2.1, showing a striking parallelism, en- 

 tirely different from the beech, and accentuating what has been 

 said about the difference of light-needing and shade-enduring 

 species. It is stated by the author, however, that, on account 

 of their concrete conditions the pine areas are not fully compar- 

 able to the beech areas. Having been allowed to grow up in 

 abnormally dense position for 37 and 57 j^ears before the thin- 

 nings, the crowns had not yet been able to attain the optimum 

 of their development, beyond which first a reduction of assimi- 

 lation may take place. In this connection Hartig is cited as 

 having found that White Pine groivn i7i dense stand for 20 to 2^ 



