@Sandrine: Thank you Sandrine!
These are a kind of Pine, conifer tree called a Japanese Spruce.
Because of a large-scale typhoon in 1959, trees were blown over.
As the result of this, the forest was exposed to the sunlight and the wind.
And the number of hikers has increased because of the completion of the highway.
As a result, no kind of moss can grow at all, just the short bamboo grasses instead, which the deer really like to eat.
As this change goes on, the deer's natural habitat has been expanded,and the deer began to eat the bark of Japanese Spruce as well.
Because of this phenomenon, the declining number of Japanese Spruce has got worse.
In this way, the resuscitation of the forest has been hindered since then.
An action of various nature reproduction is considered to be it now.
@Daroru: Mt.Odaigahara is located between the prefectures of Mie and Nara, Japan.
Because of the Isewan-Typhoon in 1959, trees were blown over.
The forest was exposed to the sunlight and the wind.
As a result, no kind of moss can grow at all, just the short bamboo grasses instead, which the deer really like to eat.
As this change goes on, the deer's natural habitat has been expanded,and the deer began to eat the bark of a tree.
The resuscitation of the forest has been hindered since then.