Abstract
Aim Prevailing ecological theory predicts that species should shift poleward in latitude as climate warms, which broadly assumes that temperature change drives distributional change. However, during a period of past warming at the last glacial retreat, species shifted their geographic ranges in many different directions. This dichotomy raises the question of whether present day range shifts in response to anthropogenic climate change are uniform (as predicted by theory and readily assumed) or multidirectional (as empirically observed in the past). To address this, we identify the distance and direction of contemporary tree range shifts. Location The continental United States (U.S.). Time Period Data collection spanned 2012–2022. Major Taxa Studied U.S. trees. Methods Using data from the U.S. Forest Service's Forest Inventory and Analysis (FIA) database, we summarize the geographic ranges of 215 trees at continental scales partitioned into their distinct life history stages (seedling, sapling, adult) to produce three analysable range polygons for each species. With this approach, life stage serves as a proxy for time, in which we assume each life stage represents a different establishment time on the landscape, thereby snapshotting a species' range at three discrete, past timesteps. For each species, we quantify a range shift as a change in range size, position, and direction between all life‐stage comparisons (e.g., adult to sapling ). We summarize these data among all 215 species to detect prevailing range shift patterns. Results We find that U.S. trees have shifted their range centers distances of 49 km and that these range movements have occurred in all cardinal directions, not exclusively poleward. Despite testing three different methods of drawing the underlying range polygons from which we derive our range shift metrics, the results are broadly consistent. Conclusions Our data confirm tree range shifts are evident in the recent past, on the decadal scales we approximate, but do not support the common expectation of uniform poleward movement. Our study is limited in its ability to forecast ongoing or future trends. However, the variability we detect suggests multifaceted drivers likely influence range shift dynamics.