Forest Tree Reproduction: Influence of Air Pollutants

Sexual reproduction of forest trees is critically important for maintenance of genetic flexibility and the persistence of most species in natural forest communities. Reproductive strategies, however, are typically beset by a variety of “weak points” and reproductive growth of many forest trees is, at best, irregular and quite unpredictable. Generally there is a very good correlation between tree vigor and the capacity for flowering and fruiting (Kozlowski, 1971). A variety of environmental constraints imposes restrictions on tree reproductive processes. Because air contaminants may reduce tree vigor and in view of the fact that numerous potential points of interaction have been identified between air pollutants and reproductive elements (Figure 7-1), it has been hypothesized that air contaminants may impact forest ecosystems by influencing reproductive processes.