The Age and Density of Ancient and Modern Oak Wood in Streams and Sediments

Abstract

SUMMARYLarge wood of oak trees (Quercus spp.) has resided in the streams and sediments of north Missouri, USA for many thousands of years. This wood affords the opportunity to compare a chronosequence of differences in wood density over a very long period. We analyzed the relationship between the age (residence time) and density of heartwood from oak boles using tree-ring and 14 C dating methods and discuss their implications. The residence time of large oak wood (> 25 cm diameter) sampled in the streams and sediments ranged from less than 14 years to more than 12,320 years. The oak wood ranged in density from 0.82 g cm -3 for a tree that had recently fallen into the stream to 0.14 g cm -3 for ancient oak wood. Two regression equations relate age (residence time) and density of oak wood and explain 88 percent of the variance in the dependent variables. Equation 1, heartwood density = age, can be used for studies in carbon cycling, wood as invertebrate habitat, or other questions related to the density and ecology of wood in streams such as wood retention and export. Equation 2, age = heartwood density, can be used for estimating when oak wood was formed on a very coarse scale over many thousands of years.

The Temporal Distribution and Carbon Storage of Large Oak Wood in Streams and Floodplain Deposits

“…Wood samples (n = 180) were first placed into broad age classes using an age-density regression developed by Guyette and Stambaugh (2003). Samples were then evaluated for suitability for radiocarbon dating.…”

“…Mass was calculated by multiplying the estimated volume of each piece of LOW by its wood density. Wood density was calculated using the volume and dry weight of a small sample (Guyette and Stambaugh 2003) of each piece of LOW. Because whole trees were generally buried or submerged (actual bole length was not measurable), wood volume was estimated by multiplying diameter by average bole length of oaks (11.6 m), the measurement from the ground to the first large branch.…”

“…The attrition or depletion of wood in streams is a process that is more or less continuous over millennia. LOW stored for more than 12,000 years in stream sediments that have not been visibly reworked and redeposited (that is, bark and sapwood still intact) has a mass loss of more than 75% (density, <0.15 g cm )3 ) due to cell wall degradation (Guyette and Stambaugh 2003). The resulting weakness of the wood probably greatly enhances its degradation when it is excavated by the stream channel after more than 5,000 years in floodplain storage.…”

“…Carbon sequestration in wood is a function of the rate at which C is assimilated by the living tree and the time it is stored in the dead components of the tree. Although C storage in forests is typically limited by the relatively rapid decay of wood after the death of a tree, C assimilated in trees that enter aquatic systems as large wood often decays very slowly in submerged or buried environments (Guyette and others 2002;Guyette and Stambaugh 2003).…”

Oak growth in Midwestern North America linked with post glacial climate epochs in the North Atlantic

“…Oaks that were dated between 9.5 and 14 cal ka BP using 14 C and density dating (Guyette and Stambaugh, 2003) showed decreased growth ( Fig. 1) and depleted δ 13 C (Fig.…”