Wisteria is called a twining vine because is climbs by wrapping itself around the stems of other woody plants (or even one of its own stems). As the vine and the host plant continue to expand in girth, the host plant is constricted into interesting contorted shapes. A closer look at the twining habit also reveals that the vine may encircle its host in either a clockwise or counterclockwise direction. This directional habit is specific to species, so in our patch we are able to recognize Chinese wisteria, as opposed to Japanese wisteria, because the vine climbs from lower left to upper right in our line of sight. A more thorough discussion of wisteria can be found on the web here.
The only way to prevent the wisteria from continuing to expand and suppress more native vegetation is to take some controlling action. If you pass along the trail now, you will see that the Invasive Plant Volunteer Squad has been at work cutting the climbing vines and the shrubby wisteria plants. However, the large stems reaching into the tall trees and the effects of encircling constriction will be evident for years to come.