Regional tree growth reductions due to ambient ozone: evidence from field experiments (original) (raw)
Related papers
Impact of Ozone on the Growth and Yield of Trees: A Review
Journal of Environment Quality, 1988
Data from 25 experiments on seedlings of 43 tree species and hybrids show that ozone (0,) can reduce growth and photosynthesis at concentrations common in many areas of the USA. Seedlings have been primarily employed for such studies for logislic reasons, and will likely provide the greatest breadth of information for some time IO come. However, a number of impediments limit application of seedling response studies IO assessment of impacts on regional timber production. Large trees differ from seedlings in a number of ways, including C allocation and canopy structure, and methods must be developed IO acrount for these differences if information from seedling studies is to prove useful IO forest impact assessmenl. Understanding how competition mediates individual tree responses will require investigation of whether systematic differences of microclimate leaf morphology that exist across canopies affects foliage sensitivity IO 0,. and whether the maximum growth rates of genolypes are correlated with susceptibility IO 0,. Definitive information on these factors is necessary IO assess imparts of 0, on stand development and diameter distributions in both mulli-and single species stands. Of critical economic importance is whether 0, preferentially damages taller, more valuable individuals within stands and more valuable, faster growing stand types.
Impacts of ozone on forests: a European perspective
New Phytologist, 1998
In comparison with the effects of extended drought periods or severe nutrient stress, those of ozone are generally much milder, at least with respect to growth. However, there is substantial evidence from experiments, in the main using young saplings, that O3 does impose a stress on forest trees under European conditions. Decreased chlorophyll contents and photosynthetic rates, changes in carbon allocation, increased antioxidant activity, and reductions in biomass due to O3 have often been recorded, particularly in fast‐growing species. Furthermore, 3 appears to weaken the trees' resilience to a range of biotic and abiotic stresses. Interactions between O3 and climatic stress, in particular drought and frost hardiness, are likely to result in potentially detrimental effects.A link between the occurrence of O3 and forest damage is not unequivocally established in Europe, and the problem remains of extrapolating and/or scaling up from studies on seedlings to predict responses to O...
Ozone exposure affects tree defoliation in a continental climate
The Science of the total environment, 2017
Ground-level ozone (O3) affects trees through visible leaf injury, accelerating leaf senescence, declining foliar chlorophyll content, photosynthetic activity, growth, carbon sequestration, predisposing to pests attack and a variety of other physiological effects. Tree crown defoliation is one of the most important parameters that is representative of forest health and vitality. Effects of air pollution on forests have been investigated through manipulative experiments that are not representative of the real environmental conditions observed in the field. In this work we investigated the role of O3 concentration and other metrics (AOT40 and POD0) in affecting crown defoliation in temperate Romanian forests. The impacts of O3 were estimated in combination with nitrogen pollutants, climatic factors and orographic conditions, by applying a non-linear modelling approach (Random Forest and Generalised Regression Models). Ozone concentration and AOT40 under Romanian conditions were more i...
Tropospheric ozone: A continuing threat to global forests?
Developments in Environmental Science
Ozone (O3) has a critical role in tropospheric chemistry. It absorbs radiation in the infrared and ultraviolet regions and is very reactive and biologically toxic at appropriate levels of exposure. At the earth's surface, O3 is subject to long-range transport and is the most pervasive air pollutant affecting the world's forests today. The existence of O3 has been known since 1840 and smog-induced foliar injury on plants was first identified in the 1950s. Levels were ∼10–15 ppb during the second half of the 1800s, compared with 30–40 ppb measured as the global background today. By 2100, fully 50% (17 million km2) of world forests are predicted to be exposed to O3 at concentrations >60 ppb. Ozone induces a variety of symptoms and pattern of injury that are dependant upon species, genotype, leaf position on the plant, leaf age, exposure dynamics, and meteorological factors or growth conditions. It is absolutely essential to have knowledge on species sensitivities, O3 profile...
Influence of Ozone and Drought on Tree Growth under Field Conditions in a 22 Year Time Series
Forests
Studying the effect of surface ozone (O3) and water stress on tree growth is important for planning sustainable forest management and forest ecology. In the present study, a 22-year long time series (1998–2019) on basal area increment (BAI) and fructification severity of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H.Karst.) at five forest sites in Western Germany (Rhineland Palatinate) was investigated to evaluate how it correlates with drought and stomatal O3 fluxes (PODY) with an hourly threshold of uptake (Y) to represent the detoxification capacity of trees (POD1, with Y = 1 nmol O3 m−2 s−1). Between 1998 and 2019, POD1 declined over time by on average 0.31 mmol m−2 year−1. The BAI showed no significant trend at all sites, except in Leisel where a slight decline was observed over time (−0.37 cm2 per year, p < 0.05). A random forest analysis showed that the soil water content and daytime O3 mean concentration were the best predictors of BAI at all s...
Forests
High ozone (O3) pollution impairs the carbon and water balance of trees, which is of special interest in planted forests. However, the effect of long-term O3 exposure on tree growth and water use, little remains known. In this study, we analysed the relationships of intra-annual stem growth pattern, seasonal sap flow dynamics and xylem morphology to assess the effect of long term O3 exposure of mature O3-sensitive hybrid poplars (‘Oxford’ clone). Rooted cuttings were planted in autumn 2007 and drip irrigated with 2 liters of water as ambient O3 treatment, or 450 ppm ethylenediurea (N-[2-(2-oxo-1-imidazolidinyl)ethyl]-N0-phenylurea, abbreviated as EDU) solution as O3 protection treatment over all growing seasons. During 2013, point dendrometers and heat pulses were installed to monitor radial growth, stem water relations and sap flow. Ambient O3 did not affect growth rates, even if the seasonal culmination point was 20 days earlier on average than that recorded in the O3 protected tr...
2013
Tropospheric ozone concentration has been rising in the last decades, due to industrial and other human activities. For plants, ozone constitutes one of the most damaging air pollutants. Main effects of ozone on forest species are reviewed: visible symptoms caused by acute exposure at the anatomical, structural and metabolic level, and the long run effects on growth and development derived from chronic exposure. Particular attention is given to photosynthesis and the effects on stomatal functioning, as major ozone injuries are inflicted to the plant after entering through the stomata. Plant detoxification capacity, carbohydrate allocation, growth and development are also revised, as well as the effects at the ecosystem level, defence mechanisms of plants against ozone, and their sensitivity and tolerance. The rising problem of tropospheric ozone contamination should awaken the international awareness and measures should be taken to control ozone atmospheric levels considering their transnational implications.
Limitations and perspectives about scaling ozone impacts in trees
Environmental pollution (Barking, Essex : 1987), 2001
We review the need for scaling effects of ozone (O3) from juvenile to mature forest trees, identify the knowledge presently available, and discuss limitations in scaling efforts. Recent findings on O3/soil nutrient and O3/CO2 interactions from controlled experiments suggest consistent scaling patterns for physiological responses of individual leaves to whole-plant growth, carbon allocation, and water use efficiency of juvenile trees. These findings on juvenile trees are used to develop hypotheses that are relevant to scaling O3 effects to mature trees, and these hypotheses are examined with respect to existing research on differences in response to O3 between juvenile and mature trees. Scaling patterns of leaf-level physiological response to O3 have not been consistent in previous comparisons between juvenile and mature trees. We review and synthesize current understanding of factors that may cause such inconsistent scaling patterns, including tree-size related changes in environmen...