RESISTANCE OF CONIFERS TO CEEOSOTE INJECTION. 35 



The sapwood was extremely easy to treat. ' The oil penetrated radially in 

 from 5 to 10 seconds and ran from the tangential surfaces in streams. After 

 removal the pieces were found to be saturated with creosote. 



The heartwood pieces treated in the cylinder appeared to have been treated 

 more thoroughly than those in the penetrance apparatus. Penetration took 

 place probably through the radial ducts, but it was not accomplished without 

 the use of pressure. The piece in the nonpressure run was treated in the sum- 

 merwood only, and then only from 1 to 2 inches deep, longitudinally. The 

 summerwood was in most cases more heavily treated than the springwood, 

 but the latter was frequently treated at the ends of the tracheids near the 

 rays, where masses of dark-colored oil would collect. In the sap the summer- 

 wood was in all cases heavily treated. The springwood treated erratically 

 in some places as heavily as summerwood, in others only lightly. In this re- 

 spect the species resembled longleaf pine. Much of the springwood contained 

 golden-yellow oil as distinguished from the brownish-black oil filling the 

 summerwood. 



Except for the greater resistance, the general character of the penetrations 

 in this species was similar to that in longleaf pine. The average longitudinal 

 penetration was about 8 times the radial and 55 times the average tangential 

 penetrations. 



LOBLOLLY PINE (PINUS T^EDA). 



In the specimens of loblolly pine the growth was very rapid, some of the 

 rings being over one-half inch wide; the springwood usually was somewhat 

 wider than the summerwood. Resin passages were numerous, very large, 

 chiefly in the summerwood, and contained tyloses. Radial ducts were 

 numerous. The length of tracheids varied from 40 to 100 times their width. 



The average oven-dry weight per cubic foot of four heart specimens was 

 33.1 pounds, and of seven sap specimens 32.1 pounds. 



In the heart the summerwood was more easily penetrated than the spring- 

 wood, and resin ducts were an important factor in the penetrations. Spring- 

 wood ducts were not treated as far as summerwood ducts, although the 

 springwood itself was quite easily penetrated, and in heavily treated portions 

 the absorption appeared to be nearly as heavy as in the summerwood. The 

 medullary rays were treated about as heavily as the springwood. 



The sapwood was penetrated very rapidly, and within a few seconds after 

 applying pressure the oil ran from the tangential surfaces in streams through 

 the resin ducts. The pieces were also penetrated longitudinally within a few 

 seconds. The summerwood was in all cases heavily treated, but the spring- 

 wood only partially. Had the latter been longer under pressure, however, it 

 also would probably have been fully treated. Creosote collected in the rays 

 and in the ends of the spring tracheids which frequently also were treated for 

 their entire length. Most spring tracheids appeared to be stained when not 

 filled with oil. 



In the cylinder most heartwood pieces treated rapidly in both springwood and 

 summerwood. In the piece treated without pressure some springwood bands 

 were found where the resin ducts were penetrated, although the surrounding 

 springwood remained untreated. Many of the medullary rays were treated 

 lightly, and all of the ray ducts appeared to be filled with oil. 



In sapwood both springwood and summerwood were heavily treated. The 

 summerwood, however, appeared to be more heavily treated than the spring- 

 wood. All of the latter was stained, and there was evidence of the presence of 

 oil much lighter in color than that in the summerwood. Many spring 

 tracheids were heavily treated, especially at the ends near the medullary rays. 



