## 1 Introduction  
Headwater streams constitute over two-thirds of the cumulative drainage length of river basins [1; 2; 3; 4], and most of the headwater areas in the United States are covered by forests [5]. By constituting such a large proportion of waterways, and having the ability to affect such a large percentage of US freshwater resources, forested headwaters are crucial sites for the storage and processing of nutrients and organic matter [6; 7]. Stream metabolism reflects the primary productivity and community respiration of a stream, both of which can affect and/or be affected by the availability of nutrients, and, in the case of community respiration, by the availability of organic matter [6], making stream metabolism useful for insights into nutrient and organic matter dynamics. The trophic status, food web, and impairment status of a water body can all be investigated through stream metabolism [8; 9; 10; 11]. Stream metabolism has been measured _in situ_ for over 50 years [12; 13; 14], and there has been a recent increase in the frequency of research focused on using functional methods, such as measuring stream metabolism, to answer various questions about ecosystem status [6; 15]. Even with this rise in the number of stream metabolism studies, many have not been specific to low-gradient headwater streams [16; 17], headwater streams being those broadly classified by [PERSON] _et al._, as those of the 1 st, 2 nd, or 3 rd order. The prevailing theory, put forth by [PERSON] _et al_. [18], is that primary production in headwaters constitutes a small proportion of overall metabolism, and that these systems derive most of their energy from allochthonous input. The metabolic studies that have taken place either partially or fully in headwaters have been mostly limited to moderate or high gradient streams and perennial flow [16; 19; 20]. Little is known about metabolic processes of headwater streams in low-gradient watersheds with commonly stagnant flow. Furthermore, the majority of the research has been conducted outside of the US Gulf coastal plain, with few studies, such as that conducted by [PERSON] _et al_. [8], situated in this geographically unique ecoregion. Land usage within a watershed can alter stream metabolism by changing the sources of organic matter in the stream channel [21]. Various forestry management activities have the potential to affect the ecosystems of adjacent streams [22; 23]. Timber harvesting can potentially introduce fresh slash into water bodies [24; 25], often resulting in increases in community respiration, an example of which was reported by [PERSON] and [PERSON] [23] where logging was found to stimulate heterotrophic process. Forestry practices such as timber harvest may also increase nutrient runoff [26], possibly contributing to stream eutrophication. Eutrophication can directly increase the production and biomass of both autotrophic and heterotrophic communities, and indirectly increase heterotrophic production when autotrophic increases provide a larger carbon source in the form of decayed algae--all of which result in changes to primary production and community respiration [27]. Sediment additions from in-roads through forested tracts, and from timber harvesting, can affect both primary production and community respiration by altering stream light availability and nutrient conditions [8,23]. In addition, timber harvesting can change shade conditions along streams, increasing opportunities for instream photosynthesis and thus elevating primary productivity [21,22,23,28]. The reduction in shade can further affect streams by elevating water temperature, which influences both community respiration and, less strongly, primary productivity [29]. Consideration of these potential influences of forestry activities on stream ecosystems is especially important for land managers in the state of Louisiana, USA, as nearly 50% of the state, known by many for its vast waterways and wetlands, is forested [30].