Betula populifolia the female catkins erect. The fruit, maturing in autumn, is composed of many tiny winged seeds packed between the catkin bracts. The wood is medium hard and is used for high grade plywood, furniture, drum shells, spools and firewood. Like other North American birches, gray birch is highly resistant to the Bronze birch borer ("Agrilus anxius"). The leaves of the gray birch serve as food for various Lepidoptera, such as the leaf miner moth "Cameraria betulivora". Between about 1930 and 1950, many gray birch trees, along with paper birch and yellow birch ("Betula alleghaniensis"), were affected and killed by birch
Northern Hemisphere the Southern Hemisphere. The North Pole faces away from the galactic center of the Milky Way. This results in the Milky Way being sparser and dimmer in the Northern Hemisphere compared to the Southern Hemisphere, making the Northern Hemisphere more suitable for deep-space observation, as it is not "blinded" by the Milky Way. The Northern Hemisphere is home to approximately 6.57 billion people which is around 90% of the earth's total human population of 7.3 billion people. Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System,