Responses of forest trees to single and multiple environmental stresses from seedlings to mature plants: Past stress history, stress interactions, tolerance and acclimation

Abstract

a b s t r a c tForest trees are exposed to a myriad of single and combined stresses with varying strength and duration throughout their lifetime, and many of the simultaneous and successive stress factors strongly interact. While much progress has been achieved in understanding the effects of single stresses on tree performance, multiple interacting stress effects cannot be adequately assessed from combination of single factor analyses. In particular, global change brings about novel combinations of severity and timing of different stresses, the effects of which on tree performance are currently hard to predict. Furthermore, the combinations of stresses commonly sustained by trees change during tree ontogeny. In addition, tree photosynthesis and growth rates decline with increasing tree age and size, while support biomass in roots, stem and branches accumulates and the concentrations of non-structural carbohydrates increase, collectively resulting in an enhancement of non-structural carbon pools. In this review, tree physiological responses to key environmental stress factors and their combinations are analyzed from seedlings to mature trees. The key conclusions of this analysis are that combined stresses can influence survival of large trees even more than chronic exposure to a single predictable stress such as drought. In addition, tree tolerance to many environmental stresses increases throughout the ontogeny as the result of accumulation of non-structural carbon pools, implying major change in sensing, response and acclimation to single and multiple stresses in trees of different size and age.

Complex facilitation and competition in a temperate grassland: loss of plant diversity and elevated CO2 have divergent and opposite effects on oak establishment

“…Although there was no direct effect of herbaceous biomass on oak survival or growth (ESM 1), increased herbaceous cover in elevated CO 2 plots may have reduced abiotic stress for the germinating oak acorns under the denser herbaceous canopy. This pattern also emerged early on in oak development when oaks were smaller and likely more vulnerable to abiotic stressors, such as heat and drought (Niinemets 2010).…”

“…Tukey tests for multiple comparisons between different levels of CO 2 and time were not possible using the GLMM with a multinomial distribution in the SAS program; for this reason letters indicating significance between groups are not displayed some type of environmental severity (e.g., extreme temperatures, increased surface soil drying, and increased rates of evapotranspiration). Aboveground cover may be particularly important for smaller/younger seedlings, which tend to have less well-developed root systems and less nonstructural C reserves to survive short periods of stress (Niinemets 2010). As plants grow in size, their root systems become more developed, and they become less susceptible to short periods of extreme abiotic conditions.…”

Monoterpene responses to interacting effects of drought stress and infection by the fungus Heterobasidion parviporum in two clones of Norway spruce (Picea abies)

“…Exposure to drought may also make trees more vulnerable to insects (Gaylord et al, 2013) and pathogens (Niinemets, 2010). Drought stress enhanced the development of Diplodia pinea on Italian cypress (Madar et al, 1995), Fusarium compactum on Cupressus sempervirens (Madar et al, 1996) and Sphaeropsis sapinea on Pinus resinosa (Blodgett et al, 1997a,b).…”

Changes in Antioxidant Enzyme Activities of European Mistletoe (Viscum album L. subsp. Album) Leaves as a Response to Environmental Stress Caused by Pollution of the Atmosphere by Nitrogen Dioxide

“…Photosynthesis and growth rates decline with increasing tree age and size, while support biomass in roots, stem and branches accumulates and the concentrations of nonstructural carbohydrates increase. It was suggested that combined stresses can infl uence survival of large trees even more than chronic exposure to a single predictable stress such as drought [36].…”