The coulee environment is optimal for balsam poplars and narrow leaf cottonwoods. Moreover, there is riparian vegetation consisting of poplars and willows. They also feed on elms and poplars. In addition to these trees, there are sequoias, cedars, palms, poplars, pines, ginkgos, and more. Poplars of the cottonwood section are often wetlands or riparian trees. The landscape is dominated by aspen, poplars and spruce, occasionally interspersed with areas of grasslands. There are small villages at the foot of ravines, where poplars and willow trees grow. Many poplars are grown as ornamental trees, with numerous cultivars used. Most of the newly planted trees were black poplars and its variant, Lombardy poplars. The city contains numerous parks, with poplars and chestnut trees flanking the streets. All Riojan rivers, including the Ebro, have a row of poplars and cottonwood. The majority of white poplars in cultivation in northern Europe are female trees. Most tree species found in the area are pine, hickory, oak, pecan, and poplars. They were replaced with planted poplars and gardens built under Philip Tilden. However, it is not closely related to true lilies, tulips or poplars.