6 BULLETIN 683, U. S. DEPARTMENT OF AGRICULTURE. 
Table 3. — Computed weights of elm in different forms . 
1,000 
feet 
b. m. of 
1-inch 
lumber. 
Cord 
1.000 board feet of logs. 
Kind of elm. 
(90 
cubic 
feet 
solid 
wood). 
Doyle log rule: diameter of logs Scribner log rule: diameter of 
(inches)— logs (inches — 
6 
12 
18 
24 
6 12 
1.8 
24 
White elm, green 
White elm, air-dry.. 
Slippery elm, green. . 
Slippery elm, air-dry 
Cork elm, green 
Cork elm, air-dry 
Lbs. 
4.300 
2, 900 
4,700 
3,200 
4,500 
3,700 
Lbs. 
4,700 
3.200 
5,000 
3,400 
4.900 
4,000 
Lbs. 
55. 600 
37.400 
59'. 900 
40'. 600 
57.700 
48;i00 
Lbs. 
12.000 
8,100 
12.900 
s;soo 
12. 400 
10. 400 
Lbs. 
S.400 
5,600 
9,000 
6.100 
8,700 
7.200 
Lbs. 
7,100 
4,800 
7,600 
5,200 
7,500 
6,100 
Lbs. 
12,400 
8,300 
13, 300 
9,000 
12,800 
10, 700 
Lbs. 
9,700 
6.500 
10,500 
7.100 
10, 100 
8,400 J 
Lbs. 
7, 700 
5,200 
8,300 
5.600 
8,000 
6,700 J 
Lbs. 
7,000 
4.700 
7,600 
5.100 
7,300 
6,000 
STRUCTURE OF THE WOOD. 
Elm belongs to the group of ring porous woods, the beginning of 
each ring or layer of growth containing a band of more or less con- 
spicuous pores. Throughout the rest of the growth ring there are 
smaller pores arranged in more or less continuous wavy lines. These 
wavy lines are of assistance in distinguishing elm from other ring 
porous woods, such as the hickories, ashes, oaks, and chestnut. 
The medullary rays are narrow and not visible to the unaided eye. 
In hackberry and sugarberry, which resemble the elms in structure, 
the rays are visible. The number, size, and arrangement of large 
and small pores serve to distinguish the wood of the different species. 
Slippery elm (PL I) has several rows of large pores, and the small 
pores are in somewhat interrupted wavy lines. In the other species 
of elm there is a single row of pores at the begimiing of each annual 
ring. In cork elm (PI. II) these pores are much smaller than in 
slippery and white elm (PI. Ill), and the small pores are in very 
distinct, fairly continuous, wavy bands. 
The following key may be used to distinguish the three principal 
elm species. 1 The characteristics mentioned may be seen on a 
smoothly cut cross section. A hand lens is an efficient aid in apphung 
the key. 
Pores of late wood arranged tangentially in conspicuous wavy, usually continuous, 
bands, the pores minute. 
A. Rays very distinct to the unaided eye; heartwood indistinct, color yellowish. 
Hackberry, Celtis occidentalis. 
Sugarberry, Celtis mississippiensis. 
B. Rays barely visible to the unaided eye; heartwood distinct, color reddish brown. 
1. Pores of early wood in a band 3 or more pores wide. 
Red or Slippery Elm, Ulmus pubescens. 
i Wing elm is similar in appearance to cork elm, except that the bands of small pores are about as 
wide as the intervening spaces. Cedar elm may be distinguished by the very indistinct row of pores 
at the beginning of the annual ring. 
