In-stream large woody debris loading and riparian forest seral stage associations in the southern Appalachian Mountains

Abstract

Large woody debris (LWD) is an important ecological component of mountain streams. However, the relation of LWD loading and riparian forest composition is poorly understood in the southern Appalachians. In this study, 500-m reaches of 11 riparian forest–stream systems representing a 300-year sere were inventoried and measured to obtain quantitative estimates and descriptions of in-stream LWD. Loading volumes ranged from 7.1 to 31.2 m3/100 m of stream, or between 3.6 and 13.2 kg/m2. LWD loadings were highly variable during midseral stages of plant community succession, primarily because of the wide range in loading of American chestnut (Castaneadentata (Marsh.) Borkh.). Loadings increased linearly in late-successional through old-growth systems over a 165-year interval. Eastern hemlock (Tsugacanadensis (L.) Carrière) and American chestnut were the most dominant carry-over LWD species in midsuccessional stream systems. Loading of eastern hemlock LWD increased from midsuccessional through old-growth stages as the species became dominant in the riparian forest. Without carry-over debris, LWD loadings would be extremely low in midsuccessional stream systems. American chestnut was a major component of LWD in midsuccessional stream systems, despite the fact that it has been unavailable for recruitment for decades.

Physical Parameters of Tropical Wetlands in Lake Victoria Basin: A Case Study of Kigwal/Kimondi, Nyando and Nzoia Wetlands

“…Anthropogenic activities along the river basins could affect water flow rate within the wetlands and thus affect their retention abilities. The recorded water flow rates in the three wetland ecosystems were in accordance with EPA (1993) of between 0.001 to 0.603 m/s [22]. A strong positive statistically significant seasonal correlation between the recorded flow rate values for the three wetland ecosystems (Kigwal/ Figure 10 shows the mean surface water turbidity values for both dry and rainy seasons for Kigwal/Kimondi, River Nyando and River Nzoia wetland ecosystems.…”

“…Higher temperatures probably decrease adsorption of hydrocarbons by soil particles and the adsorbed hydrocarbons are released to water. Solubility of hydrocarbons into water is also temperature dependent, thus leading to a decrease in adsorption when temperature rises [19][20][21][22].…”

“…Water with a pH value between 8 and 9 can cause a rapid hydrolysis to the point that the degree of chemical activity is greatly diminished or lost [23,24]. Most wetland ecosystems have water pH ranging from 6.8 to 7.5 during rainy season and a pH of 7.8 to 9 during dry season [22]. The upper end of the pH limits is associated with CO 2 -free water in contact with carbonate rocks and can acquire a pH of 10 and in contact with some silicates, a pH of up to nearly 11 [4].…”

The characteristics of woody debris and sediment distribution in headwater streams, southeastern Alaska

“…Higher volumes of woody debris were found in unlogged streams compared with logged streams in the Appalachian Mountains (Hedman et al 1996). Similarly, recent research in the Pacific Northwest observed reduced numbers of woody debris pieces in streams after logging (Bilby and Ward 1991).…”

Variability of Stand Structures and Development in Old-Growth Forests in the Pacific Northwest, USA

“…Old-growth forests can contain a variety of structural features that require a long time to develop, such as large trees, snags, downed logs, and multiple canopy layers [1][2][3]. The overall stand OPEN ACCESS physiognomy has also been described as varying from containing a relatively continuous upper canopy of shade intolerant species, to a fragmented canopy, to a continuous canopy of primarily shade tolerant species [4,5].…”