Understory cover/biomass relationships in Alabama forest types

Abstract

Foliar cover is often selected over biomass as the variable to sample when inventorying agroforestry systems. To assess forage production, biomass and cover must be satisfactorily correlated. Significant cover/biomass relationships were developed for four major Alabama forest types. Conversion factors varied by forest type. These relationships provide practical application of understory cover measurements taken in forest inventories for use in multiresource assessments and in designing agroforestry systems.

Effects of overstory composition and prescribed fire on fuel loading across a heterogeneous managed landscape in the southeastern USA

“…Although forb biomass is low, these lower values are characteristic of pine plantations and pine-oak forests in Alabama (Joyce and Mitchell, 1989). The mean and range for small trees is similar to reported values from surveys done in South Carolina to assess the availability of biomass for biofuels (Conner et al, 2009).…”

Use of low‐level remote sensing to understand tree/forage spatial interactions in Agroforests

“…Sharrow (1991) reported that 10-year-old conifer trees have a detrimental effect on forage production for a distance approximating 2 canopy diameters with no effect apparent beyond that distance. Other work (Woods et al 1982, Cameron et al 1991, Joyce and Mitchell 1989 has shown a similar pattern of detrimental effects which lessen with increasing distance from the tree. The exact response of a plant to these effects varies by tree and forage species.…”

Exploring the Inclusion of Small Regenerating Trees to Improve Above-Ground Forest Biomass Estimation Using Geospatial Data

“…In general, biomass studies are highly biased in their focus on overstory trees while ignoring understory tree layers [13,[20][21][22] due to: the lack of information about underlying vegetation strata [18,23]; the complexity and diversity of understory species [13,24]; an assumption of a negative association between numerous small regenerating trees and total AGB [25,26]; and, the lack of analytical methods for, and difficulty of, calculating the contribution of sub-strata to AGB [27]. Because these underbrush strata are often composed of various-sized, varied-age heterogeneous patches and ordered in a range of vertical layers, measuring field data is either restricted in terms of accuracy or the sample is not fully representative of the whole range of understory communities at the site [28]. Hence, methods of quantifying understory biomass still contain much uncertainty.…”

“…Another approach is the indirect and non-destructive method, which characterizes biomass in understory vegetation by using the relationship between understory vegetation and canopy trees [32]. Joyce et al [28] measured the quantitative relationships between foliar cover and biomass and suggested that this cover/biomass relationship is steady at each site, therefore, biomass can be predicted using only foliar cover measurements. Percentage cover is also commonly used when quantifying understory biomass for many species [32][33][34], and it has been suggested that the combination of percentage cover and height is also useful [32].…”