c
possible to recognize black gum (
(722)
midspring aspect indicates the presence of dogwood. Pure white dots absent
from the vegetation in the midspring aspect indicates that the vegetation
contains no dogwood or of such small size as to be of no use for working on
a lathe. Pure white areas flat on the ground, irregular in size and shape, usually
Fig. 1. The conspicuously pure white crowns are all flowering dogwood, Cornus florida
L., small trees about 10 to 20 feet tall. They can be positively identified as such,
because no other tree in the local woods produces pure white flowers at this season.
Although the scale of this photograph is 1/2,400, when it is reduced to 1/40,000 the
white dots of the dogwood are still readily recognized. At any other season of the
year than Midspring, the dogwood is very much less easily recognizable than in this
stage.
more abundant and much larger on northern than southern slopes, rarely
present except after an unusually belated snow storm indicates heaps of snow.
Pure white areas not flat on the ground but at a height of 10 to 20 feet, the
dots (crowns) usually 10 to 20 feet in diameter indicates dogwood (Cornus
florida).
It should be noted, as shown in Figure 2, that photography of the same
area as that shown in figure 1 but on the lower, moister ground will show
white-barked, leafless, open, star-shaped crowns which are characteristic of
the “sycamore” (Platanus occidentalis L.) used as a substitute for mahogany
in ornamental panelling.
In a similar way June-berry bushes can be located by photographing the
woods earlier in the season when the orchards are in bloom, when the different
species of June-berry (Amelanchier) are almost as easy to recognize as is the
dogwood. By using infra-red photography or panchromatic film with a deep
red filter, the individual elms and red maples can be easily identified in photo-
graphs taken in February and March. By using color film in August it is easily
Nyssa sylvatica) in dense mixed woods.
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