Foliage damage in coniferous trees following volcanic ashfall from Mt. St. Helens

Abstract

The foliage of coniferous plants in the area to the northeast of Mt. St. Helens, Washington State, was exposed to heavy ashfall during the May 18, 1980 eruption of the volcano. Significant damage to the pre-1980 foliage occurred after the eruption and continued through the summer. The amount of damage seen on the needles was significantly related to the amount of ash on the foliage.Elevated temperatures caused the foliage damage. The presence of ash on the foliage increased the dimensions of the shoot, thus increasing the boundary layer resistance. In turn this change in geometry elevated needle temperatures. Typical maximum needle temperatures for ash-laden foliage of Abies amabilis were in the range of 35° to 45° C and were 10° C above those of plants without ash. Damage occurred to needles at 40° C after a short growth-chamber exposure. Temperatures within the ash on the foliage also exceeded 40 degrees C.Neither chemical nor mechanical (abrasion) damage occurred. There was no melting of the cuticle. The plants with ash-covered foliage did not experience lower water potentials than those of control plants. The total radiation reflected from the needles was similar for foliage with and without ash.

Puyehue-Cordón Caulle eruption of 2011: tephra fall and initial forest responses in the Chilean Andes

“…Many studies have examined effects of tephra deposition on forests, including physical and chemical effects of tephra on foliage and effects of tephra burial on survival and growth rates (Seymour et al 1983, Antos and Zobel 1984, Hinckley et al 1984, Segura et al 1994, Ayris and Delmelle 2012. In our study tree survival/mortality was not simply related to total tephra fall depth, although the observed mortality patterns are consistent with the notion that thicker deposits are associated with higher forest mortality (Burt 1961, Ayris and Delmelle 2012, Swanson et al 2013.…”

“…Tephra fall has been associated with several mechanisms for tree decline or death, including acid deposition, ash deposition effects on foliar energy and water balances, and alteration of soil gas, energy, water exchange or chemical properties (Seymour et al 1983, Hinckley et al 1984, Segura et al 1994, Ayris and Delmelle 2012. In this study, the larger mortality of evergreen N. dombeyi compared to deciduous N. pumilio, which was leafless at the time of the eruption, may provide indirect evidence that ash effects on foliage contributed to mortality.…”

A 6000‐Year Record of Forest History on Mount Rainier, Washington

“…St. Helens eruption, due to the elevation of foliage tem? peratures by the ash covering (Seymour et al 1983). …”

Forest responses to climate change in the northwestern United States: Ecophysiological foundations for adaptive management

“…High temperatures may directly damage cell membranes and disrupt structure and function of proteins, leading to a number of harmful metabolic changes (Levitt, 1980;Nilsen and Orcutt, 1996). Exposure to high temperatures at the soil surface often results in cambial girdling in open-grown seedlings (Helgerson, 1990), but exposure to heat in excess of 40 • C may lead to other injuries and mortality (Seymour et al, 1983;Seidel, 1986). Abnormalities in bud development were observed when P. menziesii seedlings were exposed to temperatures exceeding 40 • C (Apple et al, 1998).…”