Site Preparation Activities Research Articles

A machine learning approach to predict production time using real-time RFID data in industrialized building construction

Industrialized building construction is an approach that integrates manufacturing techniques into construction projects to achieve improved quality, shortened project duration, and enhanced schedule predictability. Time savings result from concurrently carrying out factory operations and site preparation activities. In an industrialized building construction factory, the accurate prediction of production cycle time is crucial to reap the advantage of improved schedule predictability leading to enhanced production planning and control. With the large amount of data being generated as part of the daily operations within such a factory, the present study proposes a machine learning approach to accurately estimate production time using (1) the physical characteristics of building components, (2) the real-time tracking data gathered using a radio frequency identification system, and (3) a set of engineered features constructed to capture the real-time loading conditions of the job shop. The results show a mean absolute percentage error and correlation coefficient of 11% and 0.80, respectively, between the actual and predicted values when using random forest models. The results confirm the significant effects of including shop utilization features in model training and suggest that predicting production time can be reasonably achieved.

Early Performance of Tree Species in a Mountain Reforestation Experiment

Climate change requires forest managers to explore new concepts in reforestation. High-elevation sites are posing challenges because the range of tree species that can cope with present and future conditions is small and limited experience with candidate species is available. Methods: We selected a mountain site with nutrient-poor silicatic soils. The previous Norway spruce (Picea abies) stand performed poorly. We established a reforestation experiment with 27 tree species that were planted in different combinations in order to evaluate silvicultural options. Site preparation activities and planting techniques reflected the locally applied regular procedures. After planting, we monitored height growth and phenological characteristics of needle/leaf development in spring. The presently dominant Norway spruce was genetically characterized. Results: Tree seedlings planted at high elevation are highly vulnerable. The temporal course of needle/leaf sprouting varies widely. Early developers are vulnerable to frost, impairing tree development. Biotic stressors such as high population densities of weevils or mice can cause high mortality. Conclusion: we suggest a conservative approach to tree species selection because present site conditions in mountain areas may impair the development of many tree species that could be viable options in a considerably warmer climate.

Short-term understory plant community responses to salvage logging in beetle-affected lodgepole pine forests

Abstract Recent bark beetle outbreaks in western North American subalpine forests have prompted managers to salvage log some beetle-affected stands. We examined the short-term (i.e., two to three years post-treatment) consequences of such salvage logging on vascular understory plant (i.e., graminoid, forb, and shrub) communities. At 24 lodgepole pine (Pinus contorta) sites in Colorado, USA, that had been attacked by mountain pine beetles (Dendroctonus ponderosae), we evaluated how logging operations impacted understory plant species richness, cover, and composition by comparing paired unlogged and logged stands. At half of the sites, we also evaluated how logging-related slash management and site preparation activities impacted understory plant cover by comparing experimentally-implemented treatments. Average total species richness increased 18% following logging due to an increase in graminoids and forbs, while average total cover decreased 33% due to a decrease in shrubs. Experimental treatments showed that, within logged stands, average total and shrub cover were greatest where slash was retained on-site and lowest where slash was taken off-site and the soil was scarified. Average exotic species richness more than doubled after logging but values were low even in logged stands, while average exotic cover was unaffected by logging. Taken together, our results suggest that salvage logging following beetle outbreaks altered understory plant communities in the short-term by making them richer, sparser, more graminoid- and forb-dominated, less shrub-dominated, and somewhat more invaded by exotics. Our results also suggest that slash management and site preparation activities can impact the magnitude of some of the understory plant community changes brought about by logging.

Airborne Fine Particulate Emissions from Construction Activities

Construction activities contribute a significant source of airborne particulate matter (PM) which causing substantial impact on air quality. This study is conducted to investigate the ambient particulate matter concentration at the construction jobsite for newly shop lot 5-storeys building in Kota Kinabalu, Malaysia. The study focusing on coarse and fine airborne particulate sizes which involved PM0.3, PM0.5, PM1 and PM2, thus to evaluate the meteorological factors namely on relative humidity, temperature and wind speed around the construction site during construction activities on PM concentrations. The study is carried out within two different construction phases to evaluate the PM emissions that sourced from the construction activities. Phase 1 is the preliminary stage of the project plan where site preparation activities are carried out, while Phase 2 is the early stage of the project plan where the superstructure construction activities will be involved. Results showed that the concentration of particulate matter collected in Phase 2 is found higher than in Phase 1, as more extensive construction activities are being carried out in Phase 2. The meteorological conditions including temperature, relative humidity and wind speed are also found to be able influenced the characterization of PM according to their sizes. Mitigation and controlling measures to alleviate the emissions of construction activities can be adopted and improved in order to reduce the atmospheric pollution that elicited by PM.

Particulate Matters Propagation by the Surface Winning

In surface winning particulate matters are generated from a range of site preparation, stockpiling, loading, transportation and processing activities. This article aims to review issues relevant to particulate matters produced by the surface winning and impact on people living near by the quarry. Due to the areal extent of the site and limitations imposed by readily available data, the article has focused upon activities associated with quarry. On the base of obtained data was composed mathematical model of the distribution of particulate matter from the source to the surroundings to visual impact of the quarry and potential impact of the particulate matters. The visualization is shown direction of particulate matters propagation and allows decide on used measures to eliminate negative impact on people and environment.

Complex effects of site preparation and harvest on snowshoe hare abundance across a patchy forest landscape

Maintaining forest biodiversity requires an understanding of how forest-dependent species respond to a variety of forestry activities. This is particularly true for mammals, which often act as keystone species or focal species for conservation efforts in forest ecosystems. Snowshoe hares (Lepus americanus) serve as an important herbivore and prey resource throughout their range in the boreal forest. We examined the response of hares to partial and clearcut harvest, site preparation activities (post-harvest burning or chemical/mechanical preparation for regrowth), and precommercial thinning, using pellet plots on 359 forest stands across an expansive landscape in northern Idaho over a 5-year period. Hares initially responded negatively to harvest, with clearcut harvest having a greater negative impact than partial harvest, and this response was exacerbated by site preparation activities. Mid-successional stands (15–40years old) that had been clear cut with site preparation treatments applied or partially harvested with no site preparations applied had greater snowshoe hare pellet counts than mature or recently harvested stands. Pre-commercial thinning had no detectable effect on hares in this landscape. Our findings suggest an interaction between site preparation and type of harvest (clear-cut vs. partial), which suggests that both the initial negative impacts and subsequent positive response to site preparation as stands age are attenuated somewhat in partially harvested vs. clear-cut stands. Our results likely relate to the influence of management activities on vegetative cover, which is strongly related to hare abundance in a variety of systems. They suggest that silvicultural activities such as site preparation could be damaging to hare populations when applied widely across landscapes, particularly when young age classes predominate. However, because the effects of harvest and site preparation are largely transitory, use of these techniques may not substantially depress hare populations if enough stands can be maintained in the 15–40year age class.

Impacts of forest management on northern forest soils

Many effects of forest management on northern soil environments are characteristic of other latitudes, as well. Nutrient removals in harvested timber are substantial, and on some sites this may influence not only the amount but also the balance of remaining plant-available nutrients in the long term. Canopy removal during harvesting influences soil temperature and moisture regimes. Physical effects of ground-based skidding may include soil structural change, influencing water retention and flow, and reducing aeration and root penetration. Higher soil temperatures in the daytime and during the growing season tend to result from the forest floor displacement and other disturbances which may result from harvesting and site preparation activities. Impairment of soil gas exchange, due to management activities, can result in increased leaching of nutrient cations where soil pH is not very low, as a consequence of carbonic acid formation. Impaired gas exchange also results in anoxic microenvironments and may result in denitrification and the reduction of manganese, iron and sulfate. Prescribed fire results in substantial nutrient losses through volatilization (notably of N and S) and, in some cases, fly-ash losses. Slashburning yields base oxides in the ash. Hydrolysis of these oxides results in increased soil pH and both, the magnitude and the duration of the pH change are influenced by soil-buffering capacity. Many of the remaining ash nutrients are soluble, plant-available, and highly susceptible to leaching. However, increased pH and sorption after burning may limit availability of micronutrient metals and phosphorus in the soil. Hydrologic behavior can be influenced by fire effects on soil hydrophobicity. Urea fertilizer use can increase soil pH in the short run and lead to increased leaching of metals and biocides associated with dispersible organic colloids. In the longer run, the soil acidification resulting from nitrification of fertilizer N can result in leaching of some heavy metal cations.

EFFECTS OF FOREST HARVESTING BEST MANAGEMENT PRACTICES ON SURFACE WATER QUALITY IN THE VIRGINIA COASTAL PLAIN

Three small watersheds located in Westmoreland County, Virginia, were monitored to evaluate the impact offorest clearcutting on surface water quality and to evaluate the effectiveness of forestry best management practices(BMPs) for minimizing hydrologic and water quality impacts associated with timber harvesting. One watershed (7.9 ha)was clearcut without implementation of BMPs, one watershed (8.5 ha) was clearcut with the implementation of BMPs anda third watershed (9.8 ha) was left undisturbed as a control. Forest clearcutting without BMP implementation reducedstorm runoff volume and did not significantly change peak flow rates. Following site preparation, both storm flowvolumes and peak flow rates decreased significantly. For the watershed with BMP implementation, storm flow volumedecreased significantly following harvest, while peak flow increased. Site preparation did not change storm flow volumesover post-harvest conditions, but did significantly reduce storm peak flow rates. Disruptions in subsurface flow pathwaysduring harvest or rapid growth of understory vegetation following harvest could have caused these hydrologic changes.Harvest and site preparation activities significantly increased the loss of sediment and nutrients during storm events.Storm event concentrations and loadings of sediment, nitrogen, and phosphorus increased significantly following forestclearcutting and site preparation of the No-BMP watershed. Both the BMP watershed and the Control watershed showedfew changes in pollutant storm concentrations or loadings throughout the study.<br><br>Results of this study indicate forest clearcutting and site preparation without BMPs can cause significant increases insediment and nutrient concentrations and loadings in the Virginia Coastal Plain. However, these impacts can be greatlyreduced by implementing a system of BMPs on the watershed during harvesting activities.

MOTCO superfund site cleanup and restoration

The MOTCO hazardous waste site is located in LaMarque Texas approximately 72 km southeast of Houston. There are approximately 38,000 Mg (42,000 tons) of hazardous and toxic waste materials in eight pits on the MOTCO site. Additionally, 36,000 Mg (40,000 tons) of lightly contaminated soil are associated with the pits. The wastes are primarily high heat content organic liquids, sludges, and solids, some containing PCB concentrations in excess of 50 mg/kg (50 ppm). The remediation project includes site preparation, excavation, equipment mobilization and erection, trial burn, incineration, demobilization, and site closure. The project is currently underway with site preparation activities, equipment erection, and one of two trial burns completed. Remediation is progressing with one of the eight waste pits completed.

Effects of Soil Compaction on Height Growth of a California Ponderosa Pine Plantation

Abstract An analysis was made of the extent to which observed variability in plantation height growth could be explained by variability in soil surface characteristics that are modified by harvesting and site preparation activities. The study was done in a 16-year-old ponderosa pine (Pinus ponderosa) plantation in the Sierra Nevada of California. Annual height growth of all 423 trees within a 0.48 ha area was measured together with soil bulk density, A-Horizon thickness, and shrub competition. Soil organic carbon and mineralizeable nitrogen were measured on a subsample of 72 trees. Trees in areas of highest bulk density grew 43% less at age 1 and 13% less at age 15 than those in areas of lowest bulk density. Annual shoot growth was markedly reduced for 4 consecutive years following 2 years of below-normal precipitation, especially in trees growing in soils of lowest bulk density. Bulk density, A-Horizon thickness, and shrub cover accounted for only 13 to 23% of variability in height growth of the 423-tree sample. These same variables, plus organic carbon and mineralizeable nitrogen, accounted for 31% of variability in height growth of the 72-tree sample. West. J. Appl. For. 1:104-108, Oct. 1986.

Sediment Concentrations from Intensively Prepared Wetland Sites¹

Abstract Suspended sediment concentrations were measured in water draining from a 5,900-acre Carolina bay undergoing conversion to loblolly pine (Pinus taeda L.) plantations. Samples were collected during the first storm-flow event of each month between January 1981 and December 1982 from subwatersheds involved in some of several phases of conversion. Suspended sediment concentration in water leaving the bay averaged only 16 mg/1 for 13 storms. Road erosion and ditch installation produced the highest suspended sediment concentrations. Suspended sediment concentrations decreased substantially with increasing distance from the sediment source. Logging and site preparation activities did not cause an appreciable increase in suspended sediment when equipment did not operate in the drainage ditches.