405 



PHYSICAL PROPERTIES OF SOME SOUTH AUSTRALIAN- 

 GROWN Pines. 



By Professor R. W. Chapman, M.A., B.C.E. 



[Read October 9. 1919.] 



The tests about to be discussed were made upon timbers 

 supplied to the Engineering Laboratory at the University by 

 the courtesy of Mr. Walter Gill, Conservator of Forests. They 

 reached the Laboratory in June, 1917, in the form of beams 

 6 ft. 6 in. long, and either 6 in. x 4 in. or 4 in. x 2 in. in 

 section, all cut from recently-felled tress grown under inside 

 plantation conditions. They were of three species, i.e., Canary 

 Island Pine (Pinus canariensis ) , Remarkable Pine (Pinus 

 insignis), and Maritime Pine (Pinus maritima) , all of which 

 have been extensively planted in this State. The specimens 

 of Pinus canariensis were from two> trees grown in Plantation 

 A, Bundaleer Forest Reserve, and felled on May 21, 1917. 

 One tree was 68 and the other 71 ft. high, and each was 15J in. 

 in diameter at the base, and showed 39 rings. The Pinus 

 insignis species were from two trees grown on a sandy loam 

 over clay subsoil at Wirrabara Forest Reserve, one being 20 

 and the other 30 years old at the time of felling, and from a 

 tree 33 years old grown on a loamy flat over a volcanic deposit 

 at Mount Burr Forest Reserve. The species of Pinus maritima 

 come from a tree 30 years old grown at Wirrabara and from 

 another tree 33 years old grown at Mount Burr. All the trees 

 had been freshly felled about a fortnight before the timber 

 reached the Laboratory. 



When the timber was received each piece was properly 

 branded and weighed, and a remarkable difference was noticed 

 between the weights of timbers of the same species from diff- 

 erent trees. Thus the average weight of the 6 in. x 4 in. 

 pieces of Pinus insignis from the 30-year-old tree from 

 Wirrabara was 38*42 lbs., or 35'46 lbs. per cub. ft., those from 

 the 20-year-old tree in the same locality averaged 56'83 lbs., 

 or 52*46 lbs. per cub. ft. ; while those from Mount Burr 

 averaged no less than 72'25 lbs., or 66'69 lbs. per cub. ft., 

 being actually heavier than water. This difference, however, 

 turned out to be almost entirely due to the moisture contents 

 of the wood, and after storing for two years in the Laboratory 

 the average weights per cub. ft. for these three trees were 

 25*94, 28*90, and 29'69 lbs., respectively, or an average of 

 27*86 lbs. per cub. ft. for the whole. Similarly the maritima 

 6 in x 4 in. pieces from Wirrabara in June, 1917, averaged 

 59*33 lbs. or 54*76 lbs. per cub. ft. ; while those from Mount 



