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Tar HisrotocicaL DirrFERENCE Betrwren Pinus TAEDA AND 
Pinus PAwustris. 
By KATHERINE GOLDEN BITTING. 
Though the structure of the wood of a tree ,will show considerable 
variation due to environment and conditions of growth, the variation will 
be manifest in the amount of wood formed, and the size of the cells. The 
-characteristics which distinguish the particular wood remain constant, no 
matter what the external conditions may be, so that it is always possible 
to distinguish the wood of any species by the use of the microscope. It 
is not always possible to distinguish woods macroscopically, even by expert 
lumber men. This is particularly true of Coniferous woods, which are 
composed of only one form of element, the tracheides. 
The close macroscopi¢al resemblance of many Conifers, coupled with 
the variety of local names possessed by nearly every species, has caused 
much confusion in the lumber business. At present when a certain lumber 
is specified in a contract, many times the only guarantee that the contract 
will be properly filled will be the resemblance to the lumber named, along 
with information as to the locality from which it was shipped, the latter 
being the more reliable, if it be known to furnish pure groups. 
Two of the hardwood Conifers which are confounded are Pinus taeda 
and Pinus palustris, or as they are more commonly known, Loblolly and 
Longleaf pine. In addition to these Loblolly has twenty-two other common 
names, and Longleaf twenty-seven, three of which are common to both. 
Pinus taeda is of wide distribution, due to its adaptability to grow in 
different soils, consequently it shows considerable variation in its annual 
growth in both height and diameter. The best lumber is obtained from 
trees grown in mixed forests on well drained and fertile soil. These trees 
give the greatest growth in height, and a slower growth in diameter, both 
varying with the age of the tree. The zones of the spring and summer 
wood in the annual ring are nearly equal in extent, the spring wood shad- 
ing gradually into the summer wood. In the gross, the zones are fairly 
distinct, but under the microscope it is difficult to define their proximate 
limit, as seen in the transverse and radial sections. The tracheides in 
