USGS Science⌕ Search

Geology topics

Richard L. Phipps

Publications and source records attributed to Richard L. Phipps.

8 recordsLinked to original sources
USGS2005

Some geometric constraints on ring-width trend

Simulations of tree rings from trees of undisturbed forest sites are used to describe natural, long-term width trends. Ring-width trends of canopy-sized white oak are simulated from regressions of BAI (ring area) data of real trees. Examples are given of a tree from a typical re-growth forest in Illinois and of a more slowly growing tree from an old-growth forest in Kentucky. The long-term width trend was simulated as being toward constant ring width regardless of growth rate of the tree. Conditions by which either increasing or decreasing ring-width trends could be simulated from the same linear BAI trend are examined. I conclude that curvilinear width trends, either increasing or decreasing, represent width adjustments to changes in growth rate ( BAI trend) after which the width trend stabilizes to a near-constant value. Interpretation of ring-width trends of trees from undisturbed stands may be useful in assessing stand disturbance history.

Tree-Ring Research↗
USGS1986

EVIDENCE FOR THREE MODERATE TO LARGE PREHISTORIC HOLOCENE EARTHQUAKES NEAR CHARLESTON, S. C.

Earthquake-induced liquefaction features (sand blows), found near Hollywood, S. C. , have yielded abundant clasts of humate-impregnated sand and sparse pieces of wood. Radiocarbon ages for the humate and wood provide sufficient control on the timing of the earthquakes that produced the sand blows to indicate that at least three prehistoric liquefaction-producing earthquakes (m//b approximately 5. 5 or larger) have occurred within the last 7,200 years. The youngest documented prehistoric earthquake occurred around 800 A. D. A few fractures filled with virtually unweathered sand, but no large sand blows, can be assigned confidently to the historic 1886 Charleston earthquake.

Conference Paper↗
USGS1979

Simulation of wetlands forest vegetation dynamics

A computer program, SWAMP, was designed to simulate the effects of flood frequency and depth to water table on southern wetlands forest vegetation dynamics. By incorporating these hydrologic characteristics into the model, forest vegetation and vegetation dynamics can be simulated. The model, based on data from the White River National Wildlife Refuge near De Witt, Arkansas, “grows” individual trees on a 20 x 20-m plot taking into account effects on the tree growth of flooding, depth to water table, shade tolerance, overtopping and crowding, and probability of death and reproduction. A potential application of the model is illustrated with simulations of tree fruit production following flood-control implementation and lumbering.

Ecological Modelling↗
USGS1979

Tree rings as indicators of hydrologic change in the Great Dismal Swamp, Virginia and North Carolina

Analyses of tree rings of large, canopy loblolly pines ( Pinus taeda L.,) growing near a drainage ditch in the Great Dismal Swamp have indicated that the tree rings are datable and hydrologically (climatically) sensitive. Climatic and prior growth factors in regression explained 87 and 71 percent of the variance of the preditching and postditching earlywood widths, respectively, and 82 and 7O percent of the latewood widths for the same time periods. Early summer precipitation was significantly, and positively, correlated with preditching latewood growth. When pre and postditching records were merged into a single record, regression analysis explained less growth variation than when the two time periods were considered individually, implying a change in growth response following ditching. Prior to ditching, growth was most limited by dry summers which followed dry summers. After ditching, growth was less strongly linked with precipitation and more strongly linked with temperature. Regression results are compatible with the contention that growing season water levels in the proximity of the collection site have been lower since ditching.

North Carolina, Virginia↗
USGS1974

The soil creep-curved tree fallacy

No evidence has been found in eastern deciduous forests to substantiate statements that curved tree trunks, downslope tilted tree trunks, and upslope trailing tree root systems are the result of soil creep. Curvature and tilting of trunks are described as geotropic and phototropic responses to physical and physiological conditions unrelated to soil creep. The occurrence of upslope trailing of roots has not been demonstrated.

Journal of Research of the U.S. Geological Survey↗