By JOAN LOWY Scripps Howard News Service M ale dominance in the urban forest may be having profound and unforeseen consequences. The females produce fruit, berries, and seeds that are pollinated by the males, and therein lies the problem.
Many people consider the fruit and seeds dropped by female trees to be annoying litter.
The result is a male dominance along city streets that has completely skewed the natural balance of the sexes among trees, Ogren said. Seasonal allergies have more than tripled in the last generation. They now afflict 38 percent of the population, but scientists have been unable to confirm the cause of the allergy explosion. Asthma rates also have skyrocketed. Between 1980 and 1994, the prevalence of asthma in the United States increased 75 percent overall and 160 percent among children under age 5, according to the federal Centers for Disease Control and Prevention.