26 BULLETIN 606, IT. S. DEPARTMENT OF AGRICULTURE. 



Maple, sugar {Acer saccTiarum)— heartwood. — Sugar maple is a 

 diffuse-porous wood. In the specimens tested tyloses were not pres- 

 ent in either sapwood or heartwood, but gums and infiltrating sub- 

 stances were present. The specimens showed a more or less variable 

 penetration. In the cylinder treatments some of the pieces were well 

 penetrated and others were penetrated but a short distance or in 

 streaks. Creosote penetrated chiefly in the wood prosenchyma, 

 although it was also present to some extent in the vessels. The pres- 

 ence of gums seems to be responsible for the variable penetrations 

 secured in the tests. 



Oak, bur (Quercus macrocarpa). — Tyloses are numerous in both 

 sapwood and heartwood of bur oak. The effect of tyloses on pene- 

 tration is very marked in this species, and it was found to be almost 

 impossible to penetrate the heartwood to an appreciable extent. 

 Very little creosote was found in the vessels, which seemed to be 

 effectively blocked by tyloses. Two or three of the specimens treated 

 in the cylinder showed a fairly good penetration in part of the wood. 

 The distinct demarcation of the treated and untreated areas seemed 

 to indicate that the wood which was penetrated might have been sap- 

 wood not clearly distinguishable before treatment. The medullary 

 rays were practically untreated in all of the tests. 



Oak, chestnut (Quercus prinus) — heartwood. — The structure of 

 chestnut oak is very similar to that of red oak, being ring-porous and 

 generally without tyloses, although botanicalb/ chestnut oak is 

 classed as a white oak. Penetrance tests could not be made "on this 

 species on account of the open condition of the vessels. Penetration 

 took place mainly in the vessels or pores. The cell walls were prac- 

 tically impenetrated by the preservative. Eailroads have frequently 

 classed this species with the white oaks and installed chestnut oak 

 ties in the track without treatment. Since the wood takes treatment 

 easily and the pores generally are without tjdoses, chestnut oak ties 

 should evidently be treated with a preservative. 



Oak, red (Quercus rubra) — heartwood. — There are practically no 

 tyloses in the vessels of red oak. On account of the very porous con- 

 dition of the wood, penetrance tests could not be made. Specimens 

 treated in the cylinder were penetrated largely in the vessels, but very 

 little in the heartwood prosenchyma. The sapwood prosenchyma, 

 however, is known to take treatment verj^ easily. 



Oak, white (Quercus alba) — heartwood. — The pores in both sap- 

 wood and heartwood of white oak are filled with tyloses. These 

 tyloses and the character of the wood prosenchyma were an important 

 factor in making it difficult to secure more than a very slight pene- 

 tration in the specimens tested. Very little creosote was found in 

 either the vessels or wood prosenchyma. The tyloses were found to 

 be unpenetrated even in those portions of the wood which had been 

 treated. 



