The name of the game is sunlight! Conifer needles need to be exposed to as much sunlight as possible so that the tree can produce food (photosynthesis). The triangle shape helps the tree by allowing more needles to “see” the sun. As a tree grows older and taller less sunlight reaches the needles on the lower part of the tree. When this happens, these lower areas shed their needles and, eventually, the branches. As an added benefit, the triangle shape also allows the tree to gather less snow weight … the snow tends to slide right off! Trees that lose their leaves (deciduous trees) do not have this problem because when it snows all their leaves are gone and there’s not much left to hold snow.