There are a variety of trees you can see in the Kanto area mountains.
Cherry Blossoms / Sakura
Sakura trees in the mountains are called "Yamazakura." They tend to bloom a little later, so if you are visiting Japan in late April, you still have a chance to view the blossoms.
Cedar / Sugi
Sugi is the national tree of Japan and produces the pollen that causes hayfever. The Jyomon sugi is a famous cedar on Yakushima that is estimated to be between 2,170 and 7,200 years old.
Japanese Larch / Karamatsu
The Japanese larch is a deciduous tree. The needles will turn bright yellow or orange in autumn, before falling off. It can grow up to 40 meters high and have a trunk 1 meter wide.
Maple / Kaede
Maples are called kaede or momiji. The Kyoto/Takao area is famous for its bright red momiji maples in fall.
Beech / Buna
The Japanese beech tree can grow up to 35 meters tall.
The mizunara tree turn red in autumn. Brown acorns appear in October.