Task: Question Answering
Input (English): Passage: If the pigeon became alert, it would often stretch out its head and neck in line with its body and tail, then nod its head in a circular pattern. When aggravated by another pigeon, it raised its wings threateningly, but passenger pigeons almost never actually fought. The pigeon bathed in shallow water, and afterwards lay on each side in turn and raised the opposite wing to dry it.The passenger pigeon drank at least once a day, typically at dawn, by fully inserting its bill into lakes, small ponds, and streams. Pigeons were seen perching on top of each other to access water, and if necessary, the species could alight on open water to drink. One of the primary causes of natural mortality was the weather, and every spring many individuals froze to death after migrating north too early. In captivity, a passenger pigeon was capable of living at least 15 years; Martha, the last known living passenger pigeon, was at least 17 and possibly as old as 29 when she died. It is undocumented how long a wild pigeon lived.The bird is believed to have played a significant ecological role in the composition of pre-Columbian forests of eastern North America. For instance, while the passenger pigeon was extant, forests were dominated by white oaks. This species germinated in the fall, therefore making its seeds almost useless as a food source during the spring breeding season, while red oaks produced acorns during the spring, which were devoured by the pigeons. The absence of the passenger pigeon's seed consumption may have contributed to the modern dominance of red oaks. Due to the immense amount of dung present at roosting sites, few plants grew for years after the pigeons left. Also, the accumulation of flammable debris (such as limbs broken from trees and foliage killed by excrement) at these sites may have increased both the frequency and intensity of forest fires, which would have favored fire-tolerant species, such as bur oaks, black oaks, and white oaks over less fire-tolerant species, such as red oaks, thus helping to explain the change in the composition of eastern forests since the passenger pigeon’s extinction (from white oaks, bur oaks, and black oaks predominating in presettlement forests, to the “dramatic expansion” of red oaks today). 
Question: What tree has dominated with the abscense of passenger pigeons?
Output (English): red oaks.