Regional growth decline of sugar maple (Acer saccharum) and its potential causes

Abstract

Sugar maple (Acer saccharum Marsh) has experienced poor vigor, regeneration failure, and elevated mortality across much of its range, but there has been relatively little attention to its growth rates. Based on a well‐replicated dendrochronological network of range‐centered populations in the Adirondack Mountains (USA), which encompassed a wide gradient of soil fertility, we observed that the majority of sugar maple trees exhibited negative growth trends in the last several decades, regardless of age, diameter, or soil fertility. Such growth patterns were unexpected, given recent warming and increased moisture availability, as well as reduced acidic deposition, which should have favored growth. Mean basal area increment was greater on base‐rich soils, but these stands also experienced sharp reductions in growth. Growth sensitivity of sugar maple to temperature and precipitation was non‐stationary during the last century, with overall weaker relationships than expected. Given the favorable competitive status and age structure of the Adirondack sugar maple populations sampled, evidence of widespread growth reductions raises concern over this ecologically and economically important tree. Further study will be needed to establish whether growth declines of sugar maple are occurring more widely across its range.

Divergent responses to climate change and disturbance drive recruitment patterns underlying latitudinal shifts of tree species

“…South of our study area, in the United States, A. rubrum and B. alleghaniensis showed northward shifts in abundance over a similar time period but, in contrast to our study, A. saccharum and F. grandifolia showed southward shifts (Fei et al, ). If the southward shift they observed for A. saccharum results from declining abundance in the northern part of their study area (Fei et al, ), this could be consistent with declining occurrence reported in the south of our study area and into New England (Bishop et al, ; Bose, Weiskittel, & Wagner, 2017b). On the other hand, reports of increasing occurrences in the south of our study area and through New England for F. grandifolia would contrast with southward shifts in abundance reported by Fei et al ().…”

Vulnerability of eastern US tree species to climate change

“…It should be noted that both these species have been expanding in some parts of New England due to release from human pressure and acid rain, and lagged climate responses from the late Holocene Vadeboncoeur et al, 2012;Vogelmann et al, 2012;Foster & D'Amato, Fig. Our analysis also highlighted the vulnerability of species such as eastern hemlock and sugar maple that have been showing signs of decline throughout their ranges due to pests (Eschtruth et al, 2006;Fisichelli et al, 2014;Popkin, 2015), and in the case of sugar maple, acid rain and other unknown causes (Kobe et al, 2002;Gavin et al, 2008;Bishop et al, 2015). The inner polygon represents the National Park, and the outer polygon represents the PACE.…”

Water availability drives gas exchange and growth of trees in northeastern US, not elevated CO2 and reduced acid deposition

“…1). While there has been a substantial reduction in acid deposition in northeastern US, there is still not a consensus that reduced pollutant loads have enhanced tree growth in temperate mesic forests91011. The simultaneous increase in water availability and decrease in acid deposition complicate our understanding of the potential benefits of reduced acid deposition.…”