Pollen induced allergy and asthma are taking increasing toll on human life and unknowingly this problem is getting accentuated due to the desire for neat looking landscapes in modern dwelling places. It is now accepted that pollen can be an environmental hazard and their count is a part of determining the quality of air in cities and towns which face many odds because of many pollutants arising out of modern living styles. The dioecious trees like poplar, willow, cedar etc have male and female flowers on separate plants and for effective pollination their number in an area has to balanced. Modern landscapers prefer male versions since they do not liter the place giving a picture perfect appearance to the area but they produce high concentration of pollen which cause allergy.
In an informative report which came out some time back, the allergen problem and its root cause were clearly brought out, resulting in a better insight into this subject. "This situation is no coincidence, according to landscape gardener, teacher and writer Thomas Ogren. He believes the steady increase in the number of seasonal allergy sufferers has its roots in a trend toward using male trees and shrubs in urban landscaping. Among the trees believed to be problematic for allergy sufferers are such popular varieties as cottonwood, willow, elm, aspen, maple and poplar"
It is remarkable that some one has been able to bring out the underlying malady that has manifested in exposing millions of children in modern well landscaped schools in North America where the pollen levels were as high as 60000 per square yard air. unknowingly these schools seem to be pushing millions of kids into the asthma abyss. In India replanting is projected as necessary to offset deforestation taking place as a part of the infrastructure building process and adequate caution is called for in deciding what type of plants should be used in this program in the light of the above report.