Growth Characteristics of Two Populations of Pinus rigida Mill. from the Pine Barrens of New Jersey

The Outer Coastal Plain of New Jersey is largely dominated by pitch pine (Pinus rigida) forests. Most of the area supports trees of normal stature (Barrens) but fairly extensive areas of pygmy forest (Plains) also are present. We compared germination and growth characteristics of two populations representing these types. Seeds derived from trees of the contrasting forms were grown under greenhouse-nursery and phytotron conditions for periods up to 5 1/2 yr. Height, growth form, and biomass comparisons were made. Significant height differnces were found in both studies while significant biomass differences were found primarily in the greenhouse-nursery study. Where significant differences existed, Plains progeny were shorter and lighter than their Barrens counterparts. Height and biomass differences were greater in older plants but statistical differences were present in seedlings < 1 yr old. Plains progeny also included a larger percentage of poor, shrubby growth forms and were markedly more precocious in regard to cone productin. We conclude that inherent characteristics of Plains trees, whether physiological or genetic, contribute in part to the stunted nature of the Plains.