Recent reports indicate several species of trees in the US eastern woodlands are not following the predictions of climate change based on rising temperatures. They instead appear to be following climate change predictions based on changes in rainfall. Over the last 30 years, the ranges for many species of trees have shifted westward, rather than northward to cooler temperatures.
Individual trees only pull up their roots and tread across the land in works of fantasy. In reality the range of a species of tree refers to the geographic area in which it thrives. The range of a species of tree shifts when its saplings fail to reach maturity in one area of its range. Other saplings, however, reach maturity in a new area. This causes the range of those tree species to shift.
Songlin Fei, Professor of Forestry and Natural Resources, and others have written about these shifts in Science Advances. He analyzed US Forest Service data about the ranges of 86 tree species. Fei observed a westward shift among the ranges of about 73% of tree species. The trees shifting westward include white oaks, sugar maples, and American hollies. Fei and others have observed a northward shift in the ranges of 62% of eastern woodland trees. The ranges for some trees have shifted both north and west.
The impact of climate change seems to no longer lie in some distant future. We may have already begun to see examples in the shift of trees.
Fei wrote that from 1987 to 2017, the average temperature in the northeast US has increased by about 0.16 C (~5 F). Since 1980, rainfall has increased in the US northeast compared to that in the 19th Century. Rainfall has decreased in the southeastern US, leading to many droughts.
Animist perspectives on these shifts
Fei and others work within the materialism of science. Animists will see this process differently. They see forests as communities of beings.
Druids may have a particularly strong connection to forests. Dr. Felicity Grove, a Druid, described an animist understanding of this process: “It is not surprising that trees are unable to thrive in harsher climates where they once would have easily survived and thrived. Given that trees can pass water to each other through root systems but now choose not to support their kin giving the appearance of migration.
“Trees have been the bearer of tidings weather-wise,” Grove continues. “Their capacity for long lives, adaption to extreme weather, and damage events such as fire, it [is] testament to their wisdom. We should be taking note of their migration as a prediction of hostile conditions to come … .”
Ellen Evert Hopman, an archdruid from the Tribe of the Oak, describes communication among trees: “We all now know that trees speak with each other via the fungal network underground, and through chemical signals from their leaves. There are other ways they communicate too, which most humans have not yet understood.”
Hopman said that she has met happy trees and angry trees. She has felt their emotions. “Surely, they will notify each other when the climate conditions become too dire,” she says. “The tree spirits will vacate their dwellings in unsuitable areas and move on to inhabit seedlings and saplings in places more hospitable.”
Different types of trees moved in different directions
This westward shift does not occur among all tree species. Deciduous trees shifted their ranges westward. These trees shed their leaves in the fall. They tend to be sensitive to changes in available water. In contrast, evergreens have greater sensitivity to temperature changes than deciduous trees. Evergreens have adapted to a colder, drier climate. As the climate warms, conifer ranges would tend to shift northwards.
Not all deciduous tree species have shifted westward. Poplars, aspens, cottonwood, and birch trees, all deciduous, moved northward. Unlike other deciduous trees, these trees use the wind for pollination. Evergreens also tend to use wind pollination. Wind pollination tended to be associated with northward movement. Animal pollination tended to be associated with westward movement.
Regional differences in range shift
According to Fei, regions in the eastern US varied the distance shifted and the proportions of the tree ranges that shifted.
The Northern Hardwood region includes northern New England, upstate New York, and the northern Upper Mississippi. About 85% of the ranges for tree species in this region shifted northward. Per decade, the median shift was about 20.1 km (~12 miles) northward.
The Central Hardwood region includes southern New England, everywhere west of the Delaware River and west of the Appalachians. It stops around southern Tennessee and the Ozarks. About 83% of the ranges for tree species in this region shifted westward. Per decade, the median shift was about 18.9 km (~11 miles) westward.
The Southern Pine Hardwood region includes New Jersey, everything east of the Appalachian Mountains, and everywhere south of Tennessee and Missouri. About 77% of the ranges for tree species in this region shifted westward. Per decade, the median shift was about 24.7 km (~15 miles) westward.
Hopman feels it is becoming harder to be a human. She urges people to wake up to “the sentience of trees; the awareness that they are beings that live between the worlds. Part of them exists underground in the realm of the Ancestors and the Fairies. Another part is in the world of the Nature Spirits. A third part of every tree exists in the Sky Realm. They are in direct communication with the stars and the sun and moon. Anyone can sit beneath a tree and be between the worlds, at will. This is why, as I like to say, ‘Every tree is a church for a Druid.’”