Computing soil creep velocity using dendrochronology

Creep is a flow type of mass movement that may proceed as slowly as a few millimeters per year; it therefore requires measurements taken over many years to calculate its velocity. Although soil creep occurs very slowly, it is a major contributor to river silt, and may also enhance landslides. This article discusses the rapid computation of creep velocity with the aid of dendrochronology. In the past few decades, dendrochronology has emerged as a branch of botany that may be utilized in various branches of science, including geomorphology. This is because it throws light on the conditions that prevailed during annual tree ring formation, and can help to determine the impacts of different parameters on tree ring formation; this knowledge may be used for a variety of purposes. The study reported here was carried out in the Nagribala Reserve Forest along the Abbottabad–Nathiagali Road, North Pakistan, on Pinus wallichiana (blue pine). Along with measuring the creep velocity, tree age and tree base height from the base of the slope were also studied to elucidate their influence on the creep velocity. The study revealed that a single slope may show different creep velocities in different portions of the slope, and that tree age has an inverse effect on creep velocity whereas tree base height from the base of the slope has little or no impact on it. The article also elaborates the afforestation history of the area and the possible contribution of this area to reservoir siltation.