Influence of Ozone and Drought on Tree Growth under Field Conditions in a 22 Year Time Series
2022
Eghdami, Hanieh | Werner, Willy | De Marco, Alessandra | Sicard, Pierre
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 sites. The highest mean score of fructification was observed during the dry years, while low level or no fructification was observed in most humid years. Combined effects of drought and O₃ pollution mostly influence tree growth decline for European beech and Norway spruce.
显示更多 [+] 显示较少 [-]