Patterns of early cohort development following shelterwood cutting in three Adirondack northern hardwood stands

Abstract

Remeasurement and chronosequence techniques were used to describe early development in three Adirondack northern hardwood stands for up to 26 years following shelterwood seed cutting to 35–65% canopy cover. Earlier herbicide treatments had controlled dense American beech ( Fagus grandifolia) understories in the stands, leaving them devoid of advance regeneration. Deer ( Odocoileus virginianus borealis) had also been reduced by hunting and through natural losses. Findings showed that total stems (stems≥0.3 m tall) and saplings (stems≥2.54 cm DBH) followed distinct patterns of development among the stands. Total stems peaked around five years after seed cutting, suggesting that most new individuals had initiated by that time. By 10 years total stems were declining substantially, indicating that crown closure had occurred and growing space was becoming limiting within the new cohort. By 19 years sapling abundance had peaked, and by 26 years numbers had begun to decline. Non-linear regression techniques were used to model consistent patterns of development among the stands. Observed patterns of self-thinning were related to the timing of canopy closure and subsequent stratification within the new cohort.