July, 1920.] 



OGUBA -.—GROWTH IN THICKNESS. 



97 



same age. There was a considerable 

 divergence of results in such measure- 

 ments by various authors ; Wigand 

 mantained that the thickness of rings 

 is the same thoughout the different 

 heights, Mohl 1 stated that it increases 

 upwardly, while R. Hartig 2 found some 

 cases of quite the reverse. According 

 to Nordinger, 3 though there ' is no de- 

 finite rule, it increases upwards in trees 

 of closed stand, but decreases in those 

 of open stand. Measurements of Th. 

 Hartig agreed with the latter. Mohl 

 found it to increase upwards, which 

 he ascribed to (a) the earlier beginning 

 of cambial activity in spring in upper 

 regions, and (h) the heigher cortical 

 pressure in lower parts. The result of 

 R. Hartig was not simple, viz., in 

 trees with small crown it increases up- 

 wards, while in those with large one 

 increases downwards. The result of 

 my own measurements with the tree 

 No. I is shown in the table Y (H, 

 height in m. ; Y, number of annual 

 rings counted from outside). 



From this table, we can see that, 

 in general, the thickness of rings in- 

 creases upwards, as w r as found by 

 Hartig in forest trees, but the minimum 

 thickness is not at the low r est level ; it 

 is at the height 1-7 in. In two other 

 trees (No. IT III), too, I recognised the 



Table IV 

 Radial curve of Sequ. washingtnniana 



1. Mohl, H. v. (1869) Ein Beitrag zur 

 Lehre von Dickernvachsthuru des StaAimes der 

 dicotylen Baunie. — Bot. Ztg., Jg. 27. 



2. Hartig, R. (1870) Zur Lehre von 

 Dickenwachstliuni der Waldbaurue. — Bot. Ztg., 

 Jg. 28. 



3. Nordlinger, N. (I860) Die tech- 

 nischen Eigenschaften der Holzer. — Start g. 



R= 



=VPX~ 



78.9 



P=i 



X 



r 



B 



a 



50 



12.13 







100 



22.73 







150 



33.69 



49.76 



+ 6.07 



200 



44.73 



50.10 



+ 6.37 



250 



55.29 



52.28 



- 3.01 



350 



57.31 



54.32 



- 2.99 



4-0 



58 85 



56.10 



- 2.75 



550 



60.06 



57.6S 



- 2.38 



650 



61.25 



59.12 



-2.13 



750 



62.28 



60.40 



- 1.88 



850 



63.28 



61.71 



- 1.57 



950 



64.21 



62.S9 



- 1.32 



1050 



65.11 



64.11 



-1.00 



1150 



65.99 



65.07 



-0.92 



1250 



66.82 



66.10 



- 0.72 



1350 



67.63 



67.0S 



- 0.55 



1150 



6S.44 



68.02 



-0.42 



1550 



• 69.23 



68.93 



-0.30 



1650 



96.99 



69.82 



-0.17 



1750 



70.74 



70 63 



-0.06 



1850 



71.50 



71,51 



+ 0.01 



1950 



72.30 



72.32 



+ 0.02 



2050 



73.03 



73.11 



+ 0.03 



2150 



73.88 



73.8S 







2250 



74.64 



74.64 



.. 



2350 



75.38 



75.27 



-0.11 



2450 



76.14 



76.10 



-0.04 



2550 



76.83 



76.80 



- 0.03 



2650 



77.53 



77.50 



-0.03 



2750 



78.28 



78.18 



-0.10 



23 



78.96 



78.84 



-0.12 



2950 



79.60 



79.50 



-0.10 



3050 



80.14 



80.15 



+ 0.01 



3150 



80.70 



80.78 



+ 0.08 



3250 



81.37 



81.41 



+ 0.04 



