Factors influencing upland oak advance reproduction in the Missouri Ozarks

Abstract

Successful oak stand regeneration requires an abundance of well developed advance reproduction. Past studies have found that oak reproduction varies on upland landscapes by inferred measures of nutrient and water supply such as site index, slope-aspect, and slope position. There is a need to relate oak reproduction to soil nutrient and water supply parameters to better understand variations in oak reproduction on upland landscapes. On the USDA Forest Service, Sinkin Experimental Forest, located in the Missouri Ozarks, we used regression models for estimating the advance reproduction density of red oaks, white oaks, and non-oaks. The abundance of red oak advance reproduction was smaller on northeast-facing slopes and inversely related to soil plant available water capacity (AWC) and soil base saturation (BS) suggesting a greater accumulation on sites having both a lesser water and nutrient supply. The abundance of non-oaks was greater on northeast-facing slopes and positively related to site index and Bs suggesting a greater accumulation on sites having a greater site quality and nutrient supply. There were no significant models relating these factors to the abundance of white oak advance reproduction however it was significantly (P [less than] 0.05) correlated to the abundance of red oak advance reproduction.