Калифорниялық Платан ағашының сипаттамасы және генетикалық өзгерістері

Species of tree

Platanus racemosa is a species of plane tree known by several common names, including California sycamore, western sycamore, California plane tree, and in North American Spanish aliso. It can be found as far north as Tehama and Humboldt counties.

This large tree grows to in height with a trunk diameter of up to one meter (three feet). The height of these trees ranges from 10 to 35 meters. A specimen on the campus of Stanford University has a trunk girth (circumference) of 10.5 feet (3 m). The trunk generally divides into two or more large trunks splitting into many branches. The bark is an attractive patchwork of white, tawny beige, pinkish gray, and pale brown. The tough and coarse grained wood is difficult to split and work. It has various uses, including acting as a meat preparation block for butchers. Many small birds feed on its fruit, and several mammals eat its twigs and bark. The pollen resulting from the hairs on the leaves and flowers of Western sycamores can be allergens for some people. New leaves are susceptible to anthracnose canker, which, when it causes a side bud to become the new leader, can create picturesque angling trunks and branches on older specimens. The form and wide canopy of the species make it an effective shade tree.

Increased human interference has made the P. racemosa more susceptible to cross breeding with other Platanus trees. This hybridization with other species like the P. x acerifolia offers the P. racemosa the advantage of resisting fungal diseases, namely the sycamore anthracnose. Interbred California sycamores are less vulnerable to this disease than the original P. racemosa as it harms their wood. However, sycamore anthracnose produces deadwood which creates a habitat for animals like wood ducks. The lack of non hybridized P. racemosa thus harms the riparian woodlands in which they thrive. Further hybridization between the P. racemosa and P. x hispanica are a threat to the genetic diversity and identity of the former. The disease combatant advantage that the hybrid provides can bring about a decline in the native tree. The ensuing decline and genetic disintegration could not only harm the tree itself, but nesting birds, monarch butterflies, and numerous other small animals that reside or find shelter within the California sycamore's shade. D. Whitlock's study on the RNA of the Platanus trees near the Sacramento River reveals that P. racemosa contains genes from P. x hispanica, which consequently demonstrates the increased erasure of the former.