The Forest dieback in Croatia, the Research on the Causes and Afforestation Procedures"Forest dieback is a global issue concerning the forests immediately impacted by techical civilization. The research is based on the knowledge, that the forest dieback is the result of industrial, urban, traffic and agricultural pollution, partly though, ty the technologies badly adapted to forest ecosystems. The micro-habitat methods helped to assess great changes in the forest soils, dry and moist sulphate deposits, nitrates and other poisons being present in Croatian forests for a considerable time now. Though different tree species react differently, sooner or later all will be destroyed through the alterations of the physiological processes in them. The results of this research should alleviate the disastrous consequences."
Anyone who reads Wit's End, and knows that I am always searching for a scientist who will state openly that ozone is killing trees, will understand why I consider the following link, which I found this morning, as a very special gift from Santa. The entire thing is a fascinating read, but all you really need to know is excerpted below.
Happy Holidays to all, and thank you for reading, and I hope you enjoy the song.
A Case Study in the San Bernardino Mountains in Southern California
Many factors increase susceptibility of forests to wildﬁre. Among them are increases in human population, changes in land use, ﬁre suppression, and frequent droughts. These and other factors have been exacerbating forest susceptibility to wildﬁres over the past century in southern California. We report on the signiﬁcant role that air pollution has had on increasing forest susceptibility to wildﬁres, based on a 1999–2003 case study in the San Bernardino Mountains.
Air pollution, speciﬁcally ozone (O3) and wet and dry deposition of nitrogenous (N) compounds as a by-product of fossil fuel combustion, has signiﬁcantly increased since urbanization and industrialization of the region after 1945. Ozone and elevated N deposition cause speciﬁc changes in forest tree carbon (C), N, and water balance that enhance individual tree susceptibility to drought, bark beetle attack, and disease, and when combined, contribute to whole ecosystem susceptibility to wildﬁre.
For example, elevated O3 and N deposition increase leaf turnover rates, leaf and branch litter, and decrease decomposability of litter, creating excessively deep litter layers in mixed-conifer forests affected by air pollutants. Elevated O3 and N deposition decrease the proportion of whole tree biomass in foliage and roots, thereby increasing tree susceptibility to drought and beetle attack. Because both foliar and root mass are compromised, carbohydrates are stored in the bole over winter. Elevated O3 increases drought stress by signiﬁcantly reducing plant control of water loss. The resulting increase in canopy transpiration, combined with O3 and N deposition-induced decreases in root mass, signiﬁcantly increases tree susceptibility to drought stress, likely contributing to successful host colonization and population increases of barkbeetles. Phenomenological and experimental evidence is presented to support the role of these factors contributing to an increase in the susceptibility of forests to wildﬁre in southern California.
Despite the level of attention given to the causative factors for increased wildﬁre activity (Westerling et al., 2006), a largely ignored contributing factor is air pollution. Chronic nitrogen (N) deposition
contributes to increased forest densiﬁcation by stimulating aboveground biomass production and enhances litter accumulation through increased needle production, turnover rates, and depressed long-term decomposition rates (Fog, 1988). Elevated ozone (O3) exposure increases tree susceptibility to drought stress through direct effects on loss of stomatal control with subsequent increased canopy transpiration, and increased successful bark beetle colonization through both increased tree drought
stress and pollutant-induced redistribution of carbohydrates to the bole. The effects of these air pollutants, combined with the human and ecological changes in the ﬁre-adapted ecosystem, have increased forest stand susceptibility to wildﬁre in southern California (Fig. 17.1).