Statistical analyses of trees produced from wind-pollinated seeds to determine levels of additive variance need to be adjusted to compensate for the relationships among the progeny. The assumption that the coefficient of relationship among the progeny is 0.25 will lead to inaccurate estimation of the additive variance if the relationships among the progeny are not entirely half-sib. Foreign pollen intrusion into the orchard pollen cloud, selfing, and reproductive phenology variation (i.e., mating proportion differences) among the parent trees may lead to varying proportions of self, self-half, half-sib, and full-sib relationships among the progeny. The variance of the coefficient of relationship from 0.25 for two coniferous seed orchards subjected to simulated selfing and foreign pollen problems illustrate the need for caaution when estimation techniques are employed.
Six-month-old and eighteen-month-old baldcypress and loblolly pine seedlings were subjected to a simulated saltwater surge (salinity = 30 parts per thousand) for 0 to 5 days followed by flushing and daily watering with fresh water. Growth, biomass, and survival were monitored for 9 weeks following inundation. Six-month-old seedlings of both species were extremely susceptible to saltwater flooding, and survival percentages declined rapidly beyond 1 day of saltwater flooding. Eighteen-month-old seedlings were better able to survive saltwater flooding, with some pine seedlings surviving up to 3 days of flooding and some baldcypress up to 4 days of flooding. The general response of surviving baldeypress seedlings to saltwater flooding was to die back and then resprout. For loblolly pine, growth was slowed until a threshold level was reached, at which point the seedlings died. There was a direct correlation between duration of saltwater flooding and diameter growth with six-month-old seedlings but not with the eighteen-month-old seedlings. There was a steady decline in diameter with increasing days of saltwater flooding in surviving eighteen-month-old baldcypress, whereas eighteen-month-old loblolly seedlings showed some diameter growth even after 3 days of saltwater flooding. Root:shoot biomass partitioning in surviving seedlings was not appreciably affected by treatments.
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.
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