LAWS OF TALL-TREE GROWTH 543 



The tallest white pine measured by the United States Forest Service 

 was 180 feet high on a stump-radius of 19.9 inches. 

 For this tree 



/i = 24.5V72 

 .-. h = OAlH 

 The tallest white pines of America, relative to their maximum pos- 

 sible still-air height, are those about 75 years old in Wisconsin, as shown 

 in the table (p. 538), where trees stand 74 feet high on a stimip diam- 

 eter of 9 . 3 inches, giving 



/t = 26.6V72" 

 .-. h = 0A5H 

 and making this tree nearly half its greatest possible still-air height. 



On comparing Wisconsin white pines with those of Pennsylvania 

 and Michigan, it will be observed that Wisconsin trees are generally 

 lower at the same age, while from the 40th to the 130th year they are 

 much slenderer. Wisconsin trees stand 75 feet high on diameters a 

 little over 9 inches, while Michigan and Pennsylvania trees of that 

 height have diameters between 12 and 14 inches. Pennsylvania pines 

 are the tallest and largest at same age. 



The tallest pine (species not given) to which I have seen reference 

 is mentioned by Mr. Greenhill in his paper on tall trees, as referred to 

 in Sproat's British Columbia (1875). This tree is given as 221 feet 

 tall on a 10-inch stump-radius. No United States tree is in the same 

 class for relative tallness with this tree, whose still-air height would be 

 about 275 feet. This tree had thus reached four-fifths the greatest 

 height it could attain in still air without bending under its own weight. 

 I would like to see this world-wonder tree !^ 



Wisconsin White Pines 



The value of h^^^Jr^ is here more variable than for any other pines 

 I have examined. It is higher than for Michigan and Pennsylvania 

 white pines from the 40th to the 110th year, and lower from the 160th 

 to the 200th. It would be of interest to know what local conditions 

 account for this. Bulletin 22 attributes the extra relative tallness of 

 Wisconsin pines from the 40th to the 100th year to the contest for 

 light with hardwood companions. When this contest is over, lake 

 winds tend to retard growth. 



1 Ed. Note. — It seems more likely that these figures are estimates than that 

 they are authentic measurements. The tree was probably a Douglas fir. 



