Methodology

Volunteers who participate in leaf litter and root and seed bank collection will be engaged in the following activities. Staff from USGS will come to your study site and supply equipment, assist with it's initial installation, and show you how to collect data with it.

Complete plot: Production plots help estimate aboveground and belowground production of baldcypress swamps in the North American Baldcypress Swamp Network. A production plot in a baldcypress swamp consists of an aboveground litter collector (leaf litter trap), which estimates aboveground production of litter material, and a belowground root ingrowth core (purple bag), which estimates production of roots.

Leaf litter trap: Litter collectors capture the autumn litter fall, which is analyzed to obtain estimates of aboveground production in the baldcypress swamps. The captured litter is sorted into leaves, reproductive structures (e.g., seeds), and twigs, and it is then weighed. The weight of the collected biomass is a reflection of the overall aboveground production of the swamp. This estimate of production is of value to measurements of carbon storage across latitudinal gradients. The litter collectors are constructed of a bucket bottom, which can float on a piece of polystyrene foam (e.g., Styrofoam®) if water levels rise in the swamp. The bucket is tethered to a small post driven in to the ground. The litter captured in the collectors clings to a removable piece of aluminum foil, which has been painted with Tanglefoot®, a sticky substance used on flypaper.

Root ingrowth core: A root ingrowth bag (purple mesh bag) helps estimate the annual root production of baldcypress swamps as part of a carbon storage study. After the bag has been set in the ground, it will be removed the following year. The muddy purple bag lying on the plastic bag (at left) had been removed from the soil and analysis of content will lead to an estimate of the annual root growth of the previous year. Bags are divided into three 10-cm sections, representing depths from 0 to 30 cm. Root bags are transported to the lab, washed by section, sorted, and weighed.

Seed bank samples: Soil is collected from each study site within the baldcypress swamp region and is used for seed bank studies. The soil is collected in a bag and then transported to the USGS National Wetlands Research Center. The soil is set out in seed bank flats at various water depths in tanks in a nursery area. The seeds that germinate from the soil show what species are present in the soil at specific baldcypress swamps and provide information on the ability of those swamps to regenerate in different hydrologic settings.

Locating by Global Positioning Satellite (GPS): Plots in the study sites of the baldcypress swamps are located by GPS for mapping purposes. Some of the project sites are fairly remote, and the GPS is a useful tool for navigating to the sites within the swamps as well as providing detailed location information. We do not recommend navigating to sites purely by GPS because the equipment can fail, and without a good mental reference point, you could become lost in the swamp. Consequently, in addition to using GPS, we have come to identify and recognize particular trees in the swamp and make our way from point to point using these trees as a guide.

Peat layer measurement: As a simple determination of peat accumulation, the depths of the peat layer are measured periodically with a measuring stick. The depths of peat vary widely from north to south across the North American Baldcypress Swamp Network.

Range finder: To measure the height of trees, we use a distance-measuring device called a range finder. The heights of trees vary widely from north to south across the North American Baldcypress Swamp Network, with the tallest trees at mid-range along the White River in Arkansas (maximum tree height is approximately 50-m tall).

Knees: The biomass of knees is estimated by using nondestructive methods to measure knee height and girth (i.e., allometric analysis). The biomass of knees is one component in the total carbon storage, along with litter production, trunk and branch material, and belowground root production.

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