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Finland:
Aerial pictures are used for administration questions.
France:
Aerial photographs are used when preparing the programs of replanting, because they
allow a simple and rapid determination of the situation and importance of the bare spaces.
Germany:
The use of aerial photographs for these purposes has now been taken up again.
Sweden:
Aerial photographs can offer much valuable information when planning clearances,
regeneration measures, etc., in the daily administration of the forests. When making visits
to the forests, aerial photographs facilitate one's personal orientation, and this is of great
value in the large forests, as well as giving a good notion of the conditions to be studied.
U. S. A.:
Most U. S. Forest Ranger headquarters have files of photos of the areas under their
jurisdiction. These photos in most cases were not taken for forestry purposes and are
mostly at a scale of 1:20.000. They are used in innumerable ways such as to locate
timber trespass, locate section corners, decide on fishing rights, etc.
Question No. 9:
After how many years are the photographs considered too old for the dif-
ferent purposes referred to?
Austria:
As the aerial pictures give informations about the stand at the time of
the aerial photography, this must be made immediately before a general
forestry surveying. Old aerial pictures are only of stand-historical interest.
Finland:
Most of the aerial pictures in Finland are taken recently, and the
question of when they must be considered as too old is therefore not yet
topical.
Germany:
For forest planning purposes the aerial pictures must not, if possible,
be more than one year old.
Italy:
At the skirts of the forest, aerial photographs more than ten years old, are
in Italy considered as useless, considering that forests with trees of different
ages, now and then marked out for cutting, and brush-wood of the Medi-
terranean type, gradually cut away, causes a never-ceasing variation of
the composition of the wooded grounds.
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