Browsing by Author "Trettin, Carl C."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Forest composition, fuel loading, and soil chemistry resulting from 50 years of forest management and natural disturbance in two southeastern Coastal Plain watersheds, USACoates, T. Adam; Johnson, Andrew; Aust, W. Michael; Hagan, Donald L.; Chow, Alex T.; Trettin, Carl C. (2020-10-01)Globally, prescribed fire, harvesting, and understory mastication, alone and in combination, are common forest management practices. Timber commodities, wildlife habitat, wildfire fuel reduction, soil conservation, and water quality are frequently targeted and assessed as these practices are utilized. In the 1960s, a study of paired, first-order watersheds was established in coastal South Carolina, USA, to evaluate the long-term impacts of forest management (i.e. prescribed fire, thinning, mastication of understory vegetation) on water quantity and quality. Following Hurricane Hugo in 1989, this included salvage logging on one watershed, but not the other. In 2015, these watersheds were comprehensively evaluated to determine differences in forest species composition, fuels, and soil chemistry. Softwood basal area was greater in the managed watershed than in the unmanaged watershed and hardwood basal area was greater in the unmanaged watershed than in the managed watershed. Total fuel mass did not differ between the two watersheds, but 1-hr and 1000-hr rotten fuel mass were greater on the unmanaged watershed. Ten-hr fuel mass was greater on the managed watershed. Calcium, nitrogen, magnesium, phosphorus, potassium, and pH differed between the litter (Oi horizon) and duff (Oe + Oa horizons) of both watersheds, but carbon only differed in the duff. Mineral soil (Ultisols, 0-10 and 10-20 cm depths) calcium and phosphorus differed between the watersheds, but pH and the other chemicals did not. Collectively, these results indicated that: (1) forest management and natural disturbance on these watersheds altered long-term forest structure; (2) different species compositions and the inclusion or exclusion of salvage logging after Hurricane Hugo produced different fuel compositions that may potentially impact potential wildfire hazard and fire behavior; (3) organisms as a primary soil-forming factor were impacted by long-term management, therefore, some soil chemical properties were affected. Collectively, these analyses highlighted the broad, long-term impacts to ecosystem properties and processes that might directly and indirectly result from active forest management and natural disturbance and the scale of site-specific assessment that might be considered when landowner objectives are targeted in forest management plans and practices.
- Loblolly pine (Pinus taeda L.) productivity 23 years after wet site harvesting and site preparation in the lower Atlantic coastal plainNeaves, Charles M., III; Aust, W. Michael; Bolding, M. Chad; Barrett, Scott M.; Trettin, Carl C.; Vance, Eric A. (2017-10-01)Ground based timber harvesting on wet sites has been linked to alteration of soil properties that may result in reduced long term site productivity. Following Hurricane Hugo in the fall of 1989, numerous salvage logging operations were conducted under high soil moisture conditions to reduce wildfire risk and salvage timber within the Francis Marion National Forest in the lower coastal plain of South Carolina. Study sites were established on wet pine flats to examine the long term effects of primary skid trails and site preparation on planted loblolly pine (Pinus taeda L.) growth. Treatment effects were analyzed as a split-plot within a randomized complete block design with 12 blocks, four levels of site preparation (none, disking, bedding, disking with bedding), and two levels of machine traffic (primary skid trail, no obvious traffic). After 23 years, bedding and disking with bedding enhanced stand density (p < 0.0001) and above ground stand biomass (p < 0.0001) relative to the disking and non-site prepared treatments. None of the site preparation treatments were effective at increasing biomass of individual trees. Mean height (p < 0.0001), DBH (p < 0.0001), and biomass of individual trees (p < 0.0001) were lower on primary skid trails than in non-trafficked areas. Traffic did not have a significant effect on stand density (p < 0.4662) or stand biomass (p = 0.1564). Selected soil physical properties and productivity measurements were similar for the non-site prepared treatment on and off primary skid trails, suggesting that 23 years is sufficient time for soils in wet flats to naturally recover from wet weather harvest disturbance. This study indicates that bedding may be the most efficient management practice to enhance long term stand productivity for loblolly pine on aeration-limited sites by increasing seedling survival. Minimizing the spatial extent of skid trails may increase growth of individual trees. (C) 2017 Elsevier B.V. All rights reserved.
- Long term effects of wet site timber harvesting and site preparation on soil properties and loblolly pine (Pinus taeda L.) productivity in the lower Atlantic Coastal PlainNeaves, Charles Mitchell III (Virginia Tech, 2017-05-22)Short term studies have suggested that ground based timber harvesting on wet sites can alter soil properties and inhibit early survival and growth of seedlings. Persistence of such negative effects may translate to losses in forest productivity over a rotation. During the fall and winter of 1989, numerous salvage logging operations were conducted during high soil moisture conditions on wet pine flats in the lower coastal plain of South Carolina following Hurricane Hugo. A long-term experiment (split-plot within an unbalanced randomized complete block design) allowed assessment of long term effects of rutted and compacted primary skid trails and subsequent site preparation on soil properties and loblolly pine (Pinus taeda L.) productivity. The experiment had 12 blocks, four levels of site preparation as the whole plot factor (bedding, disking with bedding, disking, and no site preparation), and two levels of traffic as the subplot factor (primary skid trail, no obvious traffic). After 23 years, bedding and disking with bedding treatments effectively enhanced soil physical properties and stand productivity via promoting greater survival and stocking, but had little effect on the size of individual trees relative to disking and no site preparation treatments. Primary skid trails significantly reduced the size of individual trees, but had no appreciable long term effects on soil properties or stand productivity after 23 years. The study suggests that bedding is the most efficient practice to enhance soil properties, seedling survival, and stand productivity on wet sites. However, site preparation is not necessary for these soils and sites, if strictly intended to restore soil properties and stand productivity in primary skid trails. Reduction in individual tree sizes on primary skid trails emphasizes benefits in minimizing the spatial extent of disturbance.
- Long-term watershed management is an effective strategy to reduce organic matter export and disinfection by-product precursors in source waterMajidzadeh, Hamed; Chen, Huan; Coates, T. Adam; Tsai, Kuo-Pei; Olivares, Christopher I.; Trettin, Carl C.; Uzun, Habibullah; Karanfil, Tanju; Chow, Alex T. (2019-09-18)Watershed management practices such as prescribed fire, harvesting and understory mastication can alter the chemical composition and thickness of forest detritus, thus affecting the quantity and quality of riverine dissolved organic matter (DOM). Long-term effects of watershed management on DOM composition were examined through parallel field and extraction-based laboratory studies. The laboratory study was conducted using detritus samples collected from a pair of managed and unmanaged watersheds in South Carolina, USA. Results showed that dissolved organic carbon (DOC), total dissolved nitrogen (TDN) and ammonium (NH4+-N) concentrations were higher in water extracts from the unmanaged watershed than from the managed watershed (P < 0.01). Pyrolysis gas chromatography-mass spectrometry analysis showed that water extracts from the unmanaged watershed contained more aromatic compounds than extracts from the managed watershed. For the field study, monthly water samples were collected for 1 year (2015) from the paired watersheds. DOC and TDN concentrations, as well as DOM aromaticity, were significantly higher in the unmanaged watershed than in the managed watershed for most of the year (P < 0.05) and were linked to detrital thickness, precipitation and flow patterns. The formation potential of two regulated disinfection by-products was lower in the unmanaged watershed for most of 2015 (P < 0.05). From this study, it appears that long-term watershed management practices may alter detrital mass and chemistry in ways that improve water quality.
- Soil properties in site prepared loblolly pine (Pines taeda L.) stands 25 years after wet weather harvesting in the lower Atlantic coastal plainNeaves, Charles M., III; Aust, W. Michael; Bolding, M. Chad; Barrett, Scott M.; Trettin, Carl C.; Vance, Eric A. (2017-11-15)Harvesting traffic may alter soil properties and reduce forest productivity if soil disturbances are not mitigated. Logging operations were conducted during high soil moisture conditions on the South Carolina, USA coast to salvage timber and reduce wildfire potential following Hurricane Hugo in 1989. Long term study sites were established on wet pine flats to evaluate effects of primary skid trails and site preparation on soil properties and loblolly pine productivity. The experiment was analyzed as a split-plot within an unbalanced randomized complete block design having 12 blocks, two levels of traffic (primary skid trail (On), no obvious traffic (Off)) and four levels of site preparation (bedding (Bed), disking with bedding (D/B), disking (Disk), no site preparation (None)). Remeasurement of the study was conducted in 2015 at 25 years after salvage logging (stand age 23 years). Bed and D/B treatments had greater saturated hydraulic conductivity (p = 0.0567) and macro porosity (p = 0.0071) and lower bulk density (p = 0.0226) values than Disk and None treatments. Macroporosity benefits were evident two years after site preparation installation, but bulk density and saturated hydraulic conductivity were not, suggesting these two measurements were affected over time by differences in rooting activity influenced by initial aeration benefits. Depth to iron depletion (p = 0.0055) was significantly greater and soil carbon (p < 0.0001) was significantly lower in Bed and D/B treatments due to bed elevation above the water table and improved drainage. This implies greater aeration for roots, but trade-offs in aboveground biomass and soil carbon storage. However, above and below ground carbon differences balanced one another between treatments so that combined carbon storage in soil and above ground loblolly pine biomass was not significantly different by site preparation treatment (p = 0.1127). Bed and D/B resulted in approximately double the stand biomass (p < 0.0001) and stand density (p < 0.0001) than Disk and None. Bed and D/B generally created more favorable soil properties and enhanced long term loblolly pine stand productivity. Differences in soil properties and stand productivity between traffic levels, with and without site preparation, were negligible suggesting natural soil recovery mechanisms were mitigated effects of wet site harvesting over 25 years.