Calcium addition at the Hubbard Brook Experimental Forest increases the capacity for stress tolerance and carbon capture in red spruce (Picea rubens) trees during the cold season

Abstract

Red spruce (Picea rubens Sarg.) trees are uniquely vulnerable to foliar freezing injury during the cold season (fall and winter), but are also capable of photosynthetic activity if temperatures moderate. To evaluate the influence of calcium (Ca) addition on the physiology of red spruce during the cold season, we measured concentrations of foliar polyamines and free amino acids (putative stressprotection compounds), chlorophyll (a key photosystem component), and sapwood area (a proxy for foliar biomass), for trees in Ca-addition (CaSiO 3 added) and Cadepleted (reference) watersheds at the Hubbard Brook Experimental Forest (NH, USA). Ca-addition increased concentrations of the amino acids alanine and c-aminobutyric acid (GABA) and the polyamines putrescine (Put) and spermidine (Spd) in November, and Put in February relative to foliage from the reference watershed. Consistent with increased stress protection, foliage from the Caaddition watershed had higher total chlorophyll and chlorophyll a concentrations in February than foliage from the reference watershed. In contrast, foliage from the reference watershed had significantly lower glutamic acid (Glu) and higher alanine (Ala) concentrations in February than foliage from the Ca-addition watershed. Imbalances in Ala:Glu have been attributed to cold sensitivity or damage in other species. In addition to concentration-based differences in foliar compounds, trees from the Ca-addition watershed had higher estimated levels of foliar biomass than trees from the reference watershed. Our findings suggest that Caaddition increased the stress tolerance and productive capacity of red spruce foliage during the cold season, and resulted in greater crown mass compared to trees growing on untreated soils.

Decreased water flowing from a forest amended with calcium silicate

“…Transpiration could increase either because of an increased number of stomata (i.e., more foliage on existing trees and new regeneration) or increased water-loss rate from stomata. Our evidence of increased LAI, and past measurements of greater crown density (11), foliar biomass (29), and seedling regeneration (30) at HBEF following Ca addition suggests that this ET response was because of an increased number of stomata. (Fig.…”

“…Responses to wollastonite application have included significantly improved photosynthetic function (33), larger sapwood area (an indicator of greater foliar biomass) (29), increased sugar storage and oxidative protection (34), higher phosphorus content of foliage (35), greater mycorrhizal abundance (30), and a more vigorous sugar maple population (30,36) in W1 compared with other untreated HBEF watersheds. Other plot-scale wollastonite additions at the HBEF, but outside of W1, caused increased crown vigor and xylem basal area (11), stimulated fine-root length by ∼300% (37), and resulted in generally more decline-resistant trees (11).…”

“…Persistent ET deviation throughout the fall and winter suggests a significant response of coniferous species to Ca fertilization. The health and foliar function of red spruce, the dominant conifer on W1, was notably improved by Ca addition there (29,33,34), and this species is known to photosynthesize and transpire on a year-round basis given favorable environmental conditions (40). Deficiencies of Ca impair guard cell physiology in red spruce (41), thus the Ca from wollastonite likely improved stomatal function and enhanced winter transpiration.…”

Polyamines and abiotic stress in plants: a complex relationship1

“…Studies were also conducted to demonstrate that PAs played a role in providing cold tolerance to red spruce (Schaberg et al, 2011). These studies further showed that Put content reverted back to normal homeostatic levels upon amelioration of the stress factor(s).…”

Long‐term monitoring reveals forest tree community change driven by atmospheric sulphate pollution and contemporary climate change

“…GDM can accommodate this by including geographic (temporal) distance as a covariable, but in our dataset, this created collinearity with environmental predictors. While the shift in community composition could result from natural succession, manipulative experiments have shown the direct effects of atmospheric pollution on forest tree physiology and health (Schaberg et al, ), which provides additional evidence that sulphate deposition is a major driver of forest community change.…”