The Post Oak Savannah occupies about 3.4 million hectares of gently rolling to hilly lands in east central Texas. Large post oak (Quercus stellata Wangenh.) blackjack oak (Quercus marilandica Munchh.), Eastern redcedar (Juniperus virginiana L.) and honey mesquite (Juniperus virginiana L.) usually form the overstory, often above thickets of yaupon (Ilex vomitoria), winged elm (Ulmus alata), gum bumelia (Sideroxylon lanuginosum Michx. Subsp. Oblongifolium (Nutt) T.D. Penn.), and live oak (Quercus virginiana Mill.). Historically limited to rocky hillsides and draws (Owens and Ansley 1997), these species have migrated over the last several hundred years into bottomlands where grasses once dominated, and the increase in abundance and range has fluctuated due to both the modification of the historic fire regime and overgrazing (Smeins and Fuhlendorf 1997).The primary focus of previous fire studies in the Post Oak Savannah have been ignition time, mortality rate and the effect of burning to the understory vegetation, not standing shrub biomass estimation. Biomass estimation equations developed in different regions may not be applicable to the Post Oak Savannah since these substitutions may result in substantial error (Grier and Milne 1981, Gottfried and Severson 1994). With better prediction equations for this region with an increasing Urban-Wildfire Interface, managers can more accurately estimate the potential severity of wildfires or the effects of prescribed burns (Martin et al. 1978).Biomass estimation methods that involve juniper species have focused on Pinyon-Juniper (Pinus edulis and Juniperus spp.) and overstory-understory interactions in the western states. Schnell (1976) developed biomass prediction equations tables for eastern redcedar in Georgia, Alabama Tennessee and Virginia, that required diameters at breast height (DBH) u3e 12.7 cm. Clark et al. (1986) and Phillips (1981) developed equations for estimating post oak biomass in North Carolina, South Carolina and Georgia, using DBH and total height; Phillips (1981) also age, but neither included foliage. Common in both studies was a DBH u3e 15.2 cm and total height as independent variables. There is little biomass estimation information available for gum bumelia, although Bryant and Kothmann (1979) suggested a quadratic equation might work best.The objective of this study was to develop regression models to predict the total above-ground biomass for three species commonly found in Post Oak Savannah plant communities.
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机译：Post Oak Savannah占地约340万公顷，逐渐向德克萨斯中东部的丘陵地带滚动。大型后栎（Quercus stellata Wangenh。）二十一点橡树（Quercus marilandica Munchh。），东部红柏（Juniperus virginiana L.）和蜂蜜豆科灌木（Juniperus virginiana L.）通常形成过高的树皮，通常高于above蒲（Ilex vomitoria）的灌木丛，有翼的榆树（Ulmus alata），桉树胶（Sideroxylon lanuginosum Michx。Sublong。Oblongifolium（Nutt）TD Penn。）和活橡树（Quercus virginiana Mill。）。从历史上讲，这些物种仅限于岩石山坡和平地（Owens and Ansley 1997），在过去的几百年中，这些物种迁移到了草丛曾经占主导地位的底层地区，并且由于历史性火势的改变，丰度和范围的增加也发生了波动。 （Smeins and Fuhlendorf 1997）。先前在橡树大草原地区进行的火灾研究的主要重点是着火时间，死亡率和燃烧对林下植被的影响，而不是估计灌木生物量。在不同地区开发的生物量估计方程式可能不适用于Post Oak Savannah，因为这些替代方法可能导致重大错误（Grier和Milne 1981，Gottfried和Severson 1994）。随着城市-野火交界的增加，该地区有了更好的预测方程，管理者可以更准确地估计野火的潜在严重性或处方烧伤的影响（Martin et al.1978）。涉及杜松物种的生物量估计方法集中于Pinyon西部各州的杜松（Pinus edulis和Juniperus spp。）和上层-下层之间的相互作用。 Schnell（1976）为佐治亚州，阿拉巴马州田纳西州和弗吉尼亚州的东部柳杉开发了生物量预测方程表，该表要求胸高（DBH）的直径为12.7 cm。克拉克等。 （1986）和Phillips（1981）利用DBH和总高度开发了用于估算北卡罗莱纳州，南卡罗来纳州和乔治亚州橡树后生物量的方程。菲利普斯（Phillips）（1981）也会衰老，但均未包括叶子。两项研究中的共同点是DBH为15.2 cm，总高度为自变量。尽管布赖恩特和科特曼（Bryant and Kothmann，1979）提出一个二次方程可能最有效，但关于胶梅的生物量估算信息很少。本研究的目的是建立回归模型来预测三种常见的地上生物量。发布Oak Savannah植物群落。
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