Tree regeneration following natural disturbance and harvesting indicates challenges maintaining forest composition and tree species diversity in northern USA forests

Abstract

The frequency and severity of natural disturbances and forest harvests are changing in many temperate and boreal forests worldwide, at a time when regional surveys suggest deficiencies in tree regeneration. This combination suggests the utility of assessing how regeneration existing prior to disturbance (i.e. advance regeneration) translates to forest recovery following recent disturbances.

We used repeated plot measurements from nationwide forest inventory data to link advance seedling regeneration to post‐disturbance seedling abundance and sapling recruitment across forests of the northern USA an average of 14.3 years following natural disturbances and forest harvests. Three metrics were considered: regeneration abundance, species richness and compositional similarity to the pre‐disturbance mature tree layer. Random Forest models were used to predict post‐disturbance regeneration response as a function of advance regeneration, pre‐disturbance stand attributes, disturbance type and severity, terrain and geography.

Advance seedling regeneration was moderately correlated with post‐disturbance sapling recruitment and seedling abundance, indicating that challenges in advance regeneration do tend to carry over to challenges in post‐disturbance regeneration. Regeneration challenges following natural disturbance were more acute compared with harvesting.

Higher disturbance and harvest severity were associated with more robust post‐disturbance sapling recruitment and, to a lesser extent, seedling abundance. Other influences on post‐disturbance regeneration included climate, geography, loss of particular tree genera (especially Populus ), subsequent harvesting and understory plant cover.

Synthesis and applications : Our work establishes that previously observed challenges in advance regeneration contribute to poor recovery following harvests and natural disturbances in northern USA forests. Shifts towards lower severity harvesting in the region may be exacerbating post‐disturbance regeneration challenges, ultimately leading to low tree species richness and novel composition. Our results indicate that recovery from natural disturbance may be improved through judicious post‐disturbance management, including harvesting that focuses on improving regeneration environments while also protecting important post‐disturbance structure, like surviving trees and downed wood.

Citation

Harris, Lucas B.; Pastore, Melissa A.; D'Amato, Anthony W. 2026. Tree regeneration following natural disturbance and harvesting indicates challenges maintaining forest composition and tree species diversity in northern USA forests. Journal of Applied Ecology. 63(8):e70522. 17 p. https://doi.org/10.1111/1365-2664.70522.