========================+=========================+=======
| |Number.
------------------------+-------------------------+-------
Origin of tree, | Coppice, | 136
| Seedling, | 89
------------------------+-------------------------+-------
Slope, | Gentle to medium steep, | 5
| Gentle to steep, | 24
| Gentle, | 6
| Steep, | 79
| Very steep, | 0
| Medium steep, | 61
------------------------+-------------------------+-------
Aspect, | North, | 108
| Northeast, | 16
| Northwest, | 41
| North to northwest, | 7
| North to northeast, | 3
------------------------+-------------------------+-------
Location, | Lower slope, | 23
| Middle slope, | 152
+-------------------------+-------
| Along road, | 76
| Near road, | 28
| Away from road, | 71
------------------------+-------------------------+-------
Moisture, | Dry, | 28
| Damp, | 37
| Dry to damp, | 69
| Medium dry, | 13
| Medium damp, | 20
| Windy, dry, | 8
------------------------+-------------------------+-------
Density of forest, | Dense, | 72
| Medium dense, | 97
| Rather open, | 6
------------------------+-------------------------+-------
Infection on benches, | | 36
------------------------+-------------------------+-------
Orientation of lesions, | North, | 34
| East, | 29
| South, | 14
| West, | 21
| Northeast, | 29
| Southeast, | 10
| Northwest, | 9
| Southwest, | 5
------------------------+-------------------------+-------
[Illustration: Blight Infected District at Orbisonia, Huntingdon
County, Pa.]
The most important practical point in the study of spot infections,
however, is the location of the secondary diseased trees with reference
to the original center of infection. Where a careful study has been
made, it has always been apparent that the disease spreads from an
original center of one or two trees to trees in the immediate vicinity,
as illustrated in the accompanying diagram, which is an example of a
typical small spot infection, (Fig. 4).