Frequently referred to as evergreens, pine trees bear green needles through all seasons and all types of weather. These slender green leaves do not physically appear very similar to other sorts of foliage, but they are extremely efficient. Pine needles possess the ability to convert sunlight into food even during the chilly winter months, while minimizing the loss of water through evapotranspiration during the hottest months of the year because of their reduced surface area. The streamlined photosynthetic leaves are organized into sheathed bundles that are situated in a spiraling pattern along supporting shoots. The numbers of needles in each bundle is a species-specific characteristic, hard pines usually exhibiting five in a group and soft pines only two or three.