Historical forests in the Southeastern Mixed Forest province of the United States have been less researched than other regions using historical tree surveys. We used 81,000 tree records from surveys during the 1800s to quantify composition of this ecological province. Upland oaks and pines comprised about 75% of all trees, with relatively equal composition. Oak composition may have comprised ≥ 45% to the northern and eastern sides of the province. Hickories were about 10% of composition and a few species were present at 1% to 2% composition. Currently, pine has increased to 49% composition; loblolly pine was 46% of all trees. Upland oaks decreased to 8% composition. Paralleling other historically oak- or pine-dominated regions, fire-intolerant species increased to 40% of composition, particularly early-successional sweetgum. Historical oak-pine forests mostly have converted to loblolly pine plantations and broadleaf forests in this region. A large extent of the eastern United States historically was dominated by oak or pine forests, which likely were open old growth forests due to a frequent, low-to-moderate severity fire regime that reduced tree densities and infrequently disturbed overstory trees. Open old growth forests should be recognized as distinct ecosystems with unique characteristics, ecological functioning, and associated management practices.

与其他地区相比，使用历史树木调查对美国东南混合森林省的历史森林进行的研究较少。我们使用了1800年代调查中的81,000棵树记录来量化该生态省的组成。陆地上的橡树和松树约占所有树木的75％，并且成分相对相等。橡树成分占该省北部和东部的比例可能≥45％。山胡桃木约占组成的10％，少数物种以1％至2％的组成存在。目前，松树的成分已增加到49％。火炬松占所有树木的46％。陆地橡木的成分降至8％。与其他历史上以橡树或松树为主的地区并驾齐驱，耐火树种增加到其组成的40％，特别是早期成功的甜木。在该地区，历史悠久的橡树松树林大部分已转化为火炬松人工林和阔叶林。从历史上看，美国东部大部分地区是橡树林或松树林，由于频繁，低度至中度的严重失火状况降低了树木的密度并很少扰乱过高的树木，因此它们可能是开放式的老生长森林。开放的老生长森林应被视为具有独特特征，生态功能和相关管理实践的独特生态系统。中低度火情，降低树木密度，很少干扰过高的树木。开放的老生长森林应被视为具有独特特征，生态功能和相关管理实践的独特生态系统。中低度火情，降低树木密度，很少干扰过高的树木。开放的老生长森林应被视为具有独特特征，生态功能和相关管理实践的独特生态系统。