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Individual Highlight

Physical, Chemical, and Biological Properties of Soil Under Decaying Wood in a Tropical Wet Forest in Puerto Rico

Photo of Figure 1. (A) The study sites were located in the Luquillo Experimental Forest in northeastern Puerto Rico; (B) Logs of two species and two stages of decomposition were selected (20 logs total) and paired soil and core samples were collected and; (C) PRS-probes (Plant Root Simulator) (ion exchange membranes) were collected from underneath and 50 cm away from the logs. U.S. Department of Agriculture Forest Service.Figure 1. (A) The study sites were located in the Luquillo Experimental Forest in northeastern Puerto Rico; (B) Logs of two species and two stages of decomposition were selected (20 logs total) and paired soil and core samples were collected and; (C) PRS-probes (Plant Root Simulator) (ion exchange membranes) were collected from underneath and 50 cm away from the logs. U.S. Department of Agriculture Forest Service.Snapshot : Decaying wood is related to nutrient cycling through its role as either a sink or source of nutrients; however, at micro scales, what is the effect of decaying logs on the physical, chemical, and biotic characteristics of the soil underneath?

Principal Investigators(s) :
Gonzalez, Grizelle 
Research Location : Puerto Rico
Research Station : International Institute of Tropical Forestry (IITF)
Year : 2016
Highlight ID : 1152

Summary

Samples were taken under different depth and distances from decaying logs at two stages of decay, to measure soil temperature, total and available nutrients, and root length in a tropical wet forest. Forest Service scientists found decaying wood affected physical, chemical, and biotic properties of the underlying soil. Soil temperature was less variable under the decaying logs than away from the logs. Soil under the decaying wood had fewer roots, and lower nitrate and magnesium availability than samples collected a distance of 50 cm (19.7 inches) away from the logs. Tree species and decay stage were important factors defining the effect of decaying wood on the distribution of available nutrients. Calcium, magnesium, and potassium levels were higher in the soil associated with the youngest logs, and were higher near mahogany (Swietenia macrophylla) logs. Heavy metals were also higher in the soil located near the younger logs independent of the species; other metal ions such as aluminum, and iron were higher in the soil associated with tabanuco trees (Dacryodes excelsa) and the oldest logs. These results indicate decaying wood can contribute to and generate spatial heterogeneity of soil properties.

Forest Service Partners

External Partners

  • Deborah Jean Lodge, Northern Research Station