Principal forest dieback episodes in Northern Hardwoods: Development of numeric indices of areal extent and severity

Abstract

Abstract. The incidence of forest dieback in the Northern Hardwoods biome of Canada and the United States was determined for period from 1910 to 1990. Information from annual forest service pathology inventories in the two countries and other published literature was coded to estimate yearly the severity and areal extent of dieback on white/yellow birch and sugar maple flom 1910 to 1990. Principal dieback episodes occurred as distinct waves coincident with maturation of the forest population in each of six regions. These episodes endured an average of 11 years. It is hypothesized that, once forest populations are mature, they are susceptible to extreme stresses such as freezing and drought which serve to synchronize the onset and subsidence of major dieback episodes.

Factors associated with the decline disease of sugar maple on the Allegheny Plateau

“…Insect defoliation, drought, late spring frost, and midwinter freeze-thaw cycles have been associated with the decline and mortality of sugar maple (Giese et al 1964;Kelley 1988;Bernier et al 1989;Bauce and Allen 1991;Allen et al 1992aAllen et al , 1992bKolb and McCormick 1993;Payette et al 1996;Robitaille et al 1995;Auclair et al 1997). Sugar maple decline in Pennsylvania has occurred against a background of unusual defoliations and untimely climatic stresses.…”

Genecology of 20 paper birch (Betula papyrifera Marsh.) provenances from British Columbia and northern Idaho.

“…Forest or birch dieback is a phenomenon which has been observed in stands of birch and other hardwood species in eastern Canada and the north eastern United States (Auclair et al 1997), regardless of age, vigour or stand condition (Braathe 1995). Forest dieback is defined as "the development of symptoms associated with the unnatural mortality of leaves, buds, twigs, and branches" (Auclair et al 1997 p. 176), leading to stem dieback, early leaf colouration and leaf fall, mortality of fine roots and reduced radial growth (Auclair et al 1997).…”

“…Forest dieback is defined as "the development of symptoms associated with the unnatural mortality of leaves, buds, twigs, and branches" (Auclair et al 1997 p. 176), leading to stem dieback, early leaf colouration and leaf fall, mortality of fine roots and reduced radial growth (Auclair et al 1997). …”

“…Although birch dieback commonly occurs in association with one or more insect infestations or incidences of disease, it can occur independently of these factors (Auclair et al 1997). Recent research has shown that prolonged winter thaw (reducing cold hardiness) followed by freezing temperatures are key processes leading to dieback in hardwood species (Braathe 1995;Auclair et al 1996;Zhu 2001;Zhu 2002).…”

Composition and carbon dynamics of forests in northeastern North America in a future, warmer worldThis article is one of a selection of papers from NE Forests 2100: A Synthesis of Climate Change Impacts on Forests of the Northeastern US and Eastern Canada.

“…Following up on suggestions (Pomerleau 1953;Auclair 1987;Braathe 1995) that winter climate may be involved, the work of Cox and Malcolm (1997) and Cox and Zhu (2003) indicated that various aspects of the biophysics and physiological responses of northern birches to extended winter thaws may play an important role in their decline. Using the climate records over the yellow birch range and knowledge of potentially damaging thaw-freeze events, Bourque et al (2005) projected areas of birch decline and overlaid these projections on maps of observed 1930-1960declines (prepared by Auclair 1987Braathe 1995;Auclair et al 1997). …”