Vertical overstory canopy architecture of temperate deciduous hardwood forests in the eastern United States

The stand attributes and vertical overstory profiles of plant area (the total projected surface area of all canopy elements including leaves, twigs, and stems) for 15 temperate deciduous hardwood forest types were studied and reported. The study was conducted across the eastern United States within forest type-groups of boreal hardwood, northern hardwood, and upland oak. Vertical distributions of plant area were measured with gap-fraction-based optical sensors mounted on a mobile sampling tower. In general, the stand attributes of the surveyed forest types exhibited distinct characteristics among the three type-groups. The vertical profile of the overstory plant area demonstrated significant differences among forest types and therefore represented an important architectural feature of a forest type. The vertical profile data were well described by a modified Weibull cumulative distribution function. The two model parameters, one indicating a depth for 63% foliage inclusion and the other representing skewness, were presented for each of the 15 forest types. These two model parameters can be used to depict the vertical distribution of overstory plant area in other stands of the same types. The vertical profiles of overstory plant area were related to the successional characteristics and understory tolerance.