Only females of the pineapple gall adelgid are known. Another biological threat to the Canyon is the insect known as hemlock woolly adelgid. Warmer temperatures are likely to enable the woolly adelgid to expand northward. A complete adelgid life cycle lasts two years. This is due to loss of boreal forests from hemlock woolly adelgid, logging, and pollution. Tree roots absorb and transport the product into the foliage and kill hemlock woolly adelgid. Some hemlock trees in the Nay Aug Gorge have been affected by hemlock wooly adelgid. The hemlock woolly adelgid has destroyed most of the hemlocks within the park. The Balsam woolly adelgid also has a significant impact on Pacific Northwest forests. "Abies fraseri" is severely damaged by a non-native insect, the balsam woolly adelgid ("Adelges piceae"). By the late 1990s, the adelgid population was down. These too are under attack by an introduced pest, the hemlock woolly adelgid. For example, the hemlock woolly adelgid has infested hemlock trees in southern Vermont. Like Canada hemlock, this tree suffers severely from the hemlock woolly adelgid. The beetle's lifecycle is in parallel to the lifecycle of the hemlock woolly adelgid.