to three years to build to levels where they can be readily detected. Ecology The tree can be found living in association with many forest mushrooms, such as Ramaria flavosaponaria. Paleoecology The mid-Holocene decline of hemlock populations is a much-studied phenomenon. From its foundation in the early Holocene (around 16,000 BP) in what is now the southeastern US, T. canadensis expanded rapidly and successfully into its potential range. However, palynological analyses show the hemlock population experienced a pronounced decline approximately 5,500 BP that lasted for about 1,000 years. Continued research points to other, though less dramatic, dips in Holocene hemlock populations. Pathogens, insects, and climatic change, and a combination of these, have all been proposed to explain these anomalies. The eastern hemlock increased again after the major decline, but did not recover its former place as a dominant species. Exceptional trees Due to its being a long-lived tree, several very large or otherwise impressive trees exist along the east coast of North America. One organization, the Eastern Native Tree Society (ENTS), has been particularly active in discovering and measuring these trees. In the southern Appalachians, many individuals reach tall, and one tree has been measured in the Great Smoky Mountains National Park to tall, though this tree is now dead from hemlock woolly adelgids; the tallest now surviving, the "Noland Mountain tree", is tall. Altogether, ENTS has confirmed four trees to heights of or more by climb and tape drop. In the Northeast, the tallest accurately measured tree is . This tree, named the Seneca hemlock, grows in Cook Forest State Park, PA. Above 43°N latitude, the maximum height of the species is less, under . In New England, ENTS has measured hemlocks to , although trees above are extremely rare in New England. By 44°N, the maximum height is probably not more than . Diameters of mature hemlocks range from , with trees over in diameter being very rare. In New England, the maximum diameter is . Trunk volume is the third dimension to receive attention by ENTS. Many eastern hemlocks have been modeled to over trunk volume, and the largest has been calculated to be , making it the largest natural evergreen conifer in the eastern United States. The center of maximum size development for the species is the southern Appalachians, especially the Great Smoky Mountains. Cultivation Tsuga canadensis has long been a popular tree in cultivation. The