884 FORESTRY INVESTIGATIONS U. S, DEPARTMENT OP AGRICULTURE. 



(3) The department of physical and microscopic examination of the test material. 



(4) The department of compilation and final discussion of results. 



The region of botanical distribution of any one species that is to be investigated is divided 

 into as many stations as there seem to be widely different climatic or geological differences in its 

 habitat. In each station are selected as many sites as there seem widely different soils, elevations, 

 exposures, or other striking conditions occupied by the species. An expert collector describes 

 carefully the conditions of station and site, under instructions and on blanks appended to this 

 report. Prom each site five mature trees of any one species are chosen, four of which are average 

 representatives of the general growth, the fifth, or "check" tree, the best developed that can be 

 found. The trees are felled and cut into logs of merchantable size, and from the butt end of each 

 log a disk 6 inches in height is sawed. Logs and disks are marked with numbers to indicate 

 number of tree and number of log or disk, and their north and south sides are marked; their height 

 in the tree from the ground is noted in the record. The disks are also weighed immediately, then 

 wrapped in oiled paper and packing paper, and sent by mail or express to the laboratory, to serve 

 the purpose of physical and structural examination. Some disks of the limbwood and of younger 

 trees are also collected for other physical and physiological investigations, and to serve with the 

 disks of the older trees in studying the rate of growth and other problems. 



The logs are shipped to the test laboratory, there sawed and prepared for testing, carefully 

 marked, and tested for strength. 



The fact that tests on large pieces give different values from those obtained from small pieces 

 being fully established, a number of large sticks of each species and site will be tested full length 

 in order to establish a ratio between the values obtained from the different sizes. Part of the 

 material is tested green, another part when seasoned by various methods. Finally, tests which 

 are to determine other working qualities of the various timbers, such as adapt them to various 

 uses, are contemplated 



The disks cut from each log and correspondingly marked are examined at the botanical labora- 

 tory. An endless amount of weighings, measurings, countings, computings, microscopic examina- 

 tions, and drawings is required here, and recording of the observed facts in such a manner that 

 they can be handled. Chemical investigations have also been begun in the Division of Chemistry 

 of the Department of Agriculture, the tannic contents of the woods, their distribution through the 

 tree and their relation to the conditions of growth forming the first series of these investigations. 

 It is evident that in these investigations, cariied on by competent observers, besides the main 

 object of the work, much new and valuable knowledge unsought for must come to light if the 

 investigations are carried on systematically and in the comprehensive plan laid out. Since every 

 stick and every disk is marked in such a manner that its absolute position in the tree and almost 

 the absolute position of the tree itself or at least its general condition and surroundings are known 

 and recorded, this collection will be one of the most valuable working collections ever made, allow- 

 ing later investigators to verify or extend the studies. 



This significant prophetic language also occurs in this connection, which has finally been 

 realized by the discovery of the relation between compression and beam strength: 



By and by it is expected that the number of tests neressary may be l educed considerably, when for each species 

 the relation of the diiterent exhibitions of strength can be sufficiently established, and peihaps a test for compies- 

 sion alone iarnish sufficient data to compute the strength in other directions. 



WORK AT THE TEST LABORATORY AT ST. LOUIS, MO. 

 SAWING, SrORING, AND SEASONING. 



On arrival of the logs in St. Louis they are sent to a sawmill and cut into sticks, as shown in fig. 103. 



In all cases the arrangements shown m Nos. 1 and 2 are used, except when a detailed study of the timber in all 

 parts of the cross section of the log is intended. A few of the most perfect logs of each species are cut up into small 

 sticks, as shown m Nos. 3 and 4. The logs tested for determining the effects of extracting the turpentine from the 

 Southern pitch pines were all cut into small sticks. 



In all cases a "small stick" is nominally 4 inches square, but when dressed down for testing may be as small as 

 3i inches square. The "large sticks" vary from G by 12 to 8 by 16 inches in cross section. 



All logs vaiy from 12 to 18 ieet m length. They all have a north and south diametral line, together with the 

 number of the tree and of the log plainly marked on their larger or lower ends. The stenciled lines for sawing are 



