Carl Trettin - Academia.edu (original) (raw)

Papers by Carl Trettin

Global Biogeochemical Cycles, 2022

Models are widely used to assess hydrologic impacts of land-management, land-use change and clima... more Models are widely used to assess hydrologic impacts of land-management, land-use change and climate change. Two hydrologic models with different spatial scales, MIKE SHE (spatially distributed, watershed-scale) and DRAINMOD (lumped, fieldscale), were compared in terms of their performance in predicting stream flow and water table depth in a first-order forested watershed in coastal South Carolina. The model performance was evaluated using the coefficient of determination (R 2) and Nash-Sutcliffe’s model efficiency (E). Although both models performed reasonably well in predicting monthly and annual average water table depths and stream flow with acceptable E values (0.55-0.99) for the five-year period (2003-2007), MIKE SHE yielded better results than DRAINMOD for daily hydrologic dynamics. Both models, however, showed relatively large uncertainty in simulating stream flow for dry years. The subsurface drainage predicted by MIKE SHE was lower than simulated by DRAINMOD for dry years, ...

Forest and Rangeland Soils of the United States Under Changing Conditions, 2020

Springer US, 2018

Very high resolution digital elevation models (DEM) provide the opportunity to represent the micr... more Very high resolution digital elevation models (DEM) provide the opportunity to represent the micro-level detail of topographic surfaces, thus increasing the accuracy of the applications that are depending on the topographic data. The analyses of micro-level topographic surfaces are particularly important for a series of geospatially related engineering applications. However, the generation of very high resolution DEM using, for example, LiDAR data is often extremely computationally demanding because of the large volume of data involved. Thus, we use a high-performance and parallel computing approach to resolve this big data-related computational challenge facing the generation of very high resolution DEMs from LiDAR data. This parallel computing approach allows us to generate a fine-resolution DEM from LiDAR data efficiently. We applied this parallel computing approach to derive the DEM in our study area, a bottomland hardwood wetland located in the USDA Forest Service Santee Experi...

The hydrologic regime of bottomland hardwood swamps is typically characterized as being determine... more The hydrologic regime of bottomland hardwood swamps is typically characterized as being determined by the inundation period caused by flood events. However, in the lower coastal plain of South Carolina there are large areas of bottomland hardwood swamps that adjoin freshwater tidal creeks. There has been little work in South Carolina to ascertain whether the tidal creek affects the hydrologic regime of the forested riparian zone. We established a stream stage gauge in Huger Creek, a tidal freshwater creek that drains into the Charleston harbor estuary, and a network of wells in the adjoining riparian zone to assess the hydrologic linkages between the stream and riparian zone. Groundwater levels were influenced by the tidal stream with decreasing affect as distance from the channel increased. Water table behavior adjacent to the creek was primarily controlled by tidal forcing. Groundwater levels in the interior wetland were closely related to stream stage, but mostly lacked the daily...

The appearance of a product is a primary criterion in the purchasing decisions of consumers, bein... more The appearance of a product is a primary criterion in the purchasing decisions of consumers, being at the base of selection judgement of the product's individual units quality. Appearance characters are defined by size, shape, form, colour and absence of visual defects. Appearance is utilized as a selection criterion throughout the market production chain, storage, marketing, and finally the utilization. Fish experts affirm to be able to visually discriminate among wild and reared fish of the same species by the fish colours. For the European fish market gilthead seabream (Sparus aurata) is, together with seabass (Dicentrarchus labrax), the most important marine cultured species. A novel colour calibration method based on the association between a standard colour chart and a Partial Least Squares (PLS) model developed in Matlab environment was developed. RGB declared values of the ColorCheker (24 patches) were used as y- block. The x-block was represented by the mean RGB values ...

This dataset provides estimates of mangrove extent for 2016, and mangrove change (gain or loss) f... more This dataset provides estimates of mangrove extent for 2016, and mangrove change (gain or loss) from 2000 to 2016, in major river delta regions of six countries: Gabon, Jamaica, Mozambique, Peru, Senegal, and Tanzania. For mangrove extent, a combination of Landsat 8 OLI, Sentinel-1 C-SAR, and Shuttle Radar Topography Mission (SRTM) elevation data were used to create country-wide maps of mangrove landcover extent at a 30 m resolution. For mangrove change, the global mangrove map for 2000 (Giri et al., 2010) was used as the baseline. Normalized Difference Vegetation Indices (NDVI) were calculated for every cloud- and shadow-free pixel in the Landsat 5 TM, Landsat 7 ETM+, and Landsat 8 OLI collection and used to create an NDVI anomaly from 2000 to 2016. Areas of change (loss or gain) occurred at the extremes of the cumulative anomalies.

Forest Service Research Data Archive

Global Ecology and Biogeography, 2021

SWAMP Dataset-Mangrove soil carbon-Zambezi River Delta-2012, 2020

An objective inventory of mangrove carbon stocks within the Zambezi River delta was conducted in ... more An objective inventory of mangrove carbon stocks within the Zambezi River delta was conducted in 2012. These files provide the basis for calculating the soil carbon stock to a depth of 2m.

Western Indian Ocean Journal of Marine Science, 2019

Natural recovery of mangroves in abandoned rice farming areas is important for reviving its multi... more Natural recovery of mangroves in abandoned rice farming areas is important for reviving its multiple ecosystem services including climate change mitigation. This study aims at understanding the natural recovery rate and pattern of mangroves in the abandoned rice farming areas of the Rufiji Delta. Mangrove areas were stratified into early and intermediate succession as well as old growth forest. Forty-five nested plots, fifteen at each site, were randomly selected, where plant and soil data were collected. Based on the Importance Value Index, the most abundant tree species in the early succession was Barringtonia racemosa, a mangrove associated tree species having a value of 67.9. The mangrove Avicennia marina was the most abundant in both intermediate succession and old growth forest having a value of 170.7 and 163.1, respectively. Pairwise comparison of means indicated a significant change (p< 0.05) of structural parameters with fallow age. No significant change (p > 0.05) wa...

Northern Journal of Applied Forestry, 1989

Forest drainage systems have been used effectively to remove excess water from poorly drained for... more Forest drainage systems have been used effectively to remove excess water from poorly drained forest soils and to increase site productivity. A study was conducted in northern Michigan to determine the effects of a drainage ditch on the productivity of tamarack 65 years after ditching. Site index increased 55% and average diameter increased 145% within 5 m of the ditch. There was no apparent effect of ditching on site index beyond 80 m from the ditch or diameter beyond 20 m. North. J. Appl. For. 6:107-109, September 1989.