Land‐use legacies in forests at Jefferson's Monticello plantation

Abstract

AbstractQuestionsWe evaluate the role of past land use on long‐term forest succession and ask fundamental questions: (i) are successional patterns along a chronosequence consistent through time; (ii) is past land use or physiography a greater driver of forest composition; and (iii) does forest composition converge with age?LocationThomas Jefferson's Monticello plantation, Virginia Piedmont, USA.MethodsCombining dendroecology, historical documents and a repeated vegetation survey from 1934, we reconstruct forest histories along a chronosequence that retains a temporal dimension. Tree‐ring data indicate initial canopy status and canopy release events using time series analysis with intervention detection.ResultsForest extent was lowest during Jefferson's tenure; however, tree ring and documentary evidence revealed the location of Jefferson's timber zone. Jefferson‐era trees in this zone are largely on the west slope with scattered Pinus recruitment starting in the late 18th century, followed by Quercus species. Pinus cohorts also recruited into former agricultural fields on south and east slopes in two chronosequence stages from the 20th century. Synchronized release events were observed during the early 1800s, 1850s–1860s and 1960s, indicating periods of intense forest use. Ordination of repeated vegetation surveys showed a progression in forest age that explained more variation in forest composition than elevation and slope. The forest age gradient is also evident independently from tree‐ring data, but the ordination does not show convergence in composition with forest age.ConclusionPast land use is a greater driver of forest composition than an inferred soil moisture gradient. The composition of the most recent chronosequence stage suggests that future forest dynamics may be novel compared to the prior two centuries because of differences in land use and species availability. These land‐use legacies demonstrate how colonial‐era agricultural decisions at Monticello continue to impact forest growth and composition more than two centuries later.