On 136,744 eastern US forest plots measured about 2006 and 2021, a shared change in total tree abundance explains the westward shift of tree species; the species-specific shift is northward
Fei et al. (2017) reported that 73% of 86 eastern US tree species moved their abundance centre westward from the 1980s to the 2010s, and that moisture change caused this. We did an out-of-sample test in a later period. We used 136,744 USDA Forest Inventory and Analysis base-grid plots in 37 eastern states, each measured with the national plot design at T1 (2002-2010, median 2006) and 12-18 years later (median 2021). For 133 species and three size classes, we calculated abundance-weighted centroid shifts. We divided each shift into (1) the shift expected if the species share of stems in each 1-degree cell stays constant and only total stems change, and (2) the species-specific remainder. Uncertainty comes from a grid-cell block bootstrap and a cell-wise T1/T2 permutation test. For all stems, 58% of species moved west (mean -12.7 km/decade, 95% CI -17.6 to -7.2). The expected shift from total-tree change was -8.9 km/decade (-11.8 to -5.8) and pointed west for 87% of species, because total stems increased in Minnesota, the Plains and the south-central states. The species-specific east-west shift was -3.7 km/decade (-7.8 to +0.6), with 17 species significantly west and 17 east; for trees of 5 in or more it pointed slightly east (median +4.7). The species-specific northward shift was +6.0 km/decade (+3.4 to +8.7), and the expected shift was near zero. These results held for 0.5-degree and 2-degree cells, basal-area weights, two other visit-pair rules and a leave-self-out total. Species-specific shifts did not correlate with the mean latitude or longitude of the species. Limitations: the period and method differ from Fei et al., so this does not refute their 1980s-2010s result. The shared component is common to all species at a place, but it can have climatic or non-climatic causes.
range shift · Forest Inventory and Analysis · tree species · abundance centroid · climate change · eastern United States · westward shift · decomposition · remeasured plots · forest dynamics
References
1- challengesdoi:10.1126/sciadv.1603055
We test its finding of predominantly westward tree abundance shifts in a later period on remeasured plots and find that the westward component is mostly shared total-tree change.
Cited by
5 publicationsPublic catalog entries on Sciscape.
- usesSapling offsets did not predict 15-year adult shifts of 118 tree species on 133,949 remeasured eastern US forest plots; a shared mortality gradient caused most of the northward adult shift
We use its retained FIA download and std15 plot-pair tables, and we extend its northward species-specific shift result with tree-level demographic decomposition.
- The latitude change in NEON blacklegged nymph catches reversed when the early period changed from 2016–2018 to 2017–2019
Related prior work separates components of tree abundance-center changes. It uses a different factor account and data source.
- usesMean shade tolerance of adult trees did not increase on 51,433 remeasured eastern US forest plots, 2002–2026, although saplings and stand age predicted an increase
We use its retained FIA DataMart dataset and std15 plot-pair rule (sha256-ad8a6b2e...).
- usesNon-fire tree mortality on 201,087 unharvested US forest plot intervals rose 4% per decade in 2000–2025; without ash trees the national trend was zero, and stand ageing did not explain the change
We reuse the eastern-state FIA DataMart files that this study retained (shared dataset sha256-ad8a6b2e...), for a different question.
- usesOn 136,744 remeasured eastern US forest plots, sapling-tree latitude offsets of 89 species predicted a southward shift, but trees moved north in 2006–2021, mainly by tree loss in the south
We reuse its retained FIA plot-pair tables (std15, longest) and its shared-change null for realized shifts; our realized northward shift agrees with its species-specific northward shift.