Calcium and aluminum impacts on sugar maple physiology in a northern hardwood forest

Abstract

Forests of northeastern North America have been exposed to anthropogenic acidic inputs for decades, resulting in altered cation relations and disruptions to associated physiological processes in multiple tree species, including sugar maple (Acer saccharum Marsh.). In the current study, the impacts of calcium (Ca) and aluminum (Al) additions on mature sugar maple physiology were evaluated at the Hubbard Brook Experimental Forest (Thornton, NH, USA) to assess remediation (Ca addition) or exacerbation (Al addition) of current acidified conditions. Fine root cation concentrations and membrane integrity, carbon (C) allocation, foliar cation concentrations and antioxidant activity, foliar response to a spring freezing event and reproductive ability (flowering, seed quantity, filled seed and seed germination) were evaluated for dominant sugar maple trees in a replicated plot study. Root damage and foliar antioxidant activity were highest in Al-treated trees, while growth-associated C, foliar re-flush following a spring frost and reproductive ability were highest in Ca-treated trees. In general, we found that trees on Ca-treated plots preferentially used C resources for growth and reproductive processes, whereas Al-treated trees devoted C to defense-based processes. Similarities between Al-treated and control trees were observed for foliar cation concentrations, C partitioning and seed production, suggesting that sugar maples growing in native forests may be more stressed than previously perceived. Our experiment suggests that disruption of the balance of Ca and Al in sugar maples by acid deposition continues to be an important driver of tree health.

Extreme events and subtle ecological effects: lessons from a long‐term sugar maple–American beech comparison

“…, Halman et al. ). Despite having identified thaw–freeze events, drought and forest tent caterpillar irruptions as possible causes for the 1986–1989 abrupt growth decrease, similar events did not cause such sudden growth decreases for sugar maple during the rest of the study period (Fig.…”

“…Another possible hypothesis is that soil acidification weakened sugar maple health and made it more vulnerable to other stresses like climate extremes (St. Clair et al 2008). Some studies even showed that thawfreeze events can exacerbate nutrient deficiency on sugar maple (Comerford et al 2013, Halman et al 2013. Despite having identified thawfreeze events, drought and forest tent caterpillar irruptions as possible causes for the [1986][1987][1988][1989] abrupt growth decrease, similar events did not cause such sudden growth decreases for sugar maple during the rest of the study period ( Fig.…”

Ecological benefits and risks arising from liming sugar maple dominated forests in northeastern North America

“…However, the effect of calcium addition on sap quality and yield has not yet been formally demonstrated. At the Hubbard Brook Experimental Forest in New Hampshire, calcium amendment with silicate material improved photosynthetic surface area, aboveground net primary production, tree biomass increment, reproductive ability, and extension growth (for seedlings) of sugar maple trees in the treated watershed, compared to that in the reference watershed (Halman et al 2013(Halman et al , 2014Battles et al 2014;Marlow and Peart 2014). Another study showed that calcium addition facilitated sugar maple wound closure and injury recovery from ice storm damage (Huggett et al 2007).…”

Forest biodiversity, relationships to structural and functional attributes, and stability in New England forests

“…It has the ability to extract water from deep to surface soils, which can benefit other tree species. Concerns about sugar maple decline with crown dieback, reduced growth rate, increased mortality and failed regeneration across much of its range (Bishop et al 2015) have triggered many studies searching for causes (Houston 1999;Horsley et al 2000;Hufkens et al 2012;Halman et al 2013;Bishop et al 2015;Bal et al 2017). Multiple factors likely contribute, including insect defoliation, summer drought, warmer winters, and anthropogenic acidic inputs in the last decades.…”

“…Multiple factors likely contribute, including insect defoliation, summer drought, warmer winters, and anthropogenic acidic inputs in the last decades. These have likely combined to make sugar maple less healthy and vulnerable to root diseases, nonnative earthworms, or suppression by other local tree species that are more tolerable to stressors (Houston 1999;Long et al 2009;Hufkens et al 2012;Halman et al 2013;Bishop et al 2015;Bal et al 2017).…”