22 



HARDWOOD RECORD 



proportion of good boards was 46.4 per cent. It must be remembered 

 that the selected material represents an extremely small percentage of 

 the growing timber. Practically no honeycombing or checking 

 occurred in any of the radially-sawed material, and very little in the 

 tangential. 



From examples examined, a diameter of at least sixteen inches 

 appears to be requisite before the better quality of wood begins to 

 be laid on the growing tree. The density of the wood dried in this 

 way is so great that, with the exception of sapwood, it sinks in 

 water. 



A piece of ' ' San Jose gum ' ' which was dried with the others Avas 



INCH BOARD SAWED DIAMETRICALLY THROUGH THE CENTER 

 OF A FRESH BLUE GUM LOG, SHOWING EFFECT PRODUCED 

 BY THE INTERNAL STRESSES. 



from the lower log of a tree over three feet in diameter. It slirank 

 much less than the other and was warped and corrugated but little. 



The previous experiment having shown the futility of attempting 

 to dry the ordinary run of blue gum for lumber, it was decided to 

 determine whether the largest of the ordinary blue gum trees were 

 not equal to the ' ' San Jose gum. ' ' For this purpose one of the finest 

 and largest trees growing in the region near Piedmont was obtained. 

 It was one of a splendid row, had clear trunk of twenty-four feet, 

 total height of 102, and measured thirteen feet in circumference, 

 breast high. It was said to be forty years old, but an estimate of 

 the rings gave thirty-six. Two logs were cut, the butt log numbered 

 110, the top 111, and they were cut in 1% inch boards and a few 

 pieces of % inch veneer. The entire tree was of remarkably curly grain. 

 Three of the boards measured 34% inches in width. The moisture 

 content of a sample of 110 was 90..3 per cent and of 111, 90.5 per cent. 

 A portion of the boards was steamed two hours at atmospheric pres- 

 sure, then doused in water at 150° F. These boards were marked S. 

 A few were left in the cylinder and steamed one and a half hours 

 longer at three pounds pressure, then also put into the tank. The 

 next day all were piled on trucks in the same manner as in the 

 previous experiment, together with unstcamed boards marked A, and 

 the trucks were run into the kiln. The drying was begun at a tem- 

 perature of from 130 to 133° F. and humidity of 82 per cent. The 

 boards were piled on two trucks and run into Sections II and III. 

 During the first five days the temperature of Section II was main- 

 tained at 135° and Section III at 143° and the humidities gradually 

 reduced from 80 to 60 per cent. The temperatures were finally 

 raised to 160 and 170° respectively, and the humidities reduced to 

 44 and 42 per cent. 



In fifteen days sample A 110 reached its minimum moisture condi- 

 tion of 4.3 per cent. The two other pieces, A 111 and S 111, still 

 contained 8.8 and 11,1 per cent respectively. At the end of seven- 

 teen days they ceased to lose weight, and the load was ready to take 

 out. Discs cut from eight boards in Section III showed a moisture 

 content of from 3,6 to 6,7 per cent, average 4,8 per cent, and from 

 seven boards in Section II, of from 5.4 to 9.2 per cent, average 

 5.8 per cent. The boards had dried with no honeycombing, and prac- 

 tically no cheeking, except through the center of the boards sawed 

 from across the center of the logs. The shrinkage, however, was 

 great, especially toward the center of the logs, and there was a great 

 deal of warping. The curly-grained boards warped in an undulating 

 manner in both directions, somewhat like ripples on water. The 

 straight-grained boards warped as in the previous experiment. Three 

 of the boards from log 110 were originally 34% inches wide. These 

 shrank to 32 3/16, 31%, and 30% inches. There was no honeycomb- 

 ing. On account of the curly grain this wood was not corrugated 

 in parallel ridges, as in the straight-grained wood, but was rippled 



in fine diagonal lines. The shrinkage of this tree was much less than 

 in former experiments. The boards were sawed full 1% inches. After 

 drying they measured from 13/16 to even 1% inches in jdaces, accord- 

 ing to whether the boards were radial or tangential. They averaged 

 about one inch in thickness. It would be impossible, however, to 

 plane them to this thickness, since the surface is undulating. This 

 wood does not sink in water. It is pinkish in color on the cross 

 section and resembles more nearly the San Jose specimen, but, unfor- 

 tunately, a direct comparison is not possible on account of the curly 

 grain. 



There appeared to be but little difference as to preliminary treat- 

 ment, as in the former ease. The untreated material dried as well 

 as the steamed. The latter seemed more plastic tlian the untreated, 

 and sagged more between the stickers. 



Additional tests were made in this run of the seasoning qualities 

 of different species of eucalyptus. Three trees of manna gum (Euca- 

 lyptus viminalis) were cut near the dry kiln, and logs about eighteen 

 inches in diameter were sawed into 1% inch boards. After seasoning 

 in tlie kiln the Ijoards had shrunken, corrugated, and vvarped as much 

 as the poorer pieces of blue gum, except the sapwood. The sapwood^— 

 and this alone — dried as well as would a piece of ash. This seems 

 to account for the apparently anomalous occurrence of pieces of 

 manna gum which dry fairly well — they are evidently all sapwood. 



Some boards cut from blue gum were kept three weeks in a red- 



LARGE QUARTER-SAWED BOARD NO. .V 110 TMOIinrciULY KII.N- 



DRIED. NOTE THE CHECKING THROUGH THE HEART HUT 



NOT ELSEWHERE, ALSO THE CURLY GRAIN. THE RULER 



IS TWO FEET LONG. 



wood tank of water at a temperature of 150°. When removed they 

 had turned to a bluish-black color, changing to almost jet black. 

 When this lumber had been .reasoned in the kiln it showed no advan- 

 tages over similar pieces from the same trees dried in the previous 

 experiment. 



Some boards were cut from two dead trees. One was two feet in 

 diameter, and when felled the dead leaves were still adhering to the 

 branches. The other tree had evidently been dead several years, as 



