|
|
|
|
Manual de Redacción Científica
(External Link) Urban Forest 10-20-30 Rule (External Link) How Diverse is Diverse?You may wish to aim for the 10-20-30 rule as a guide. This rule states that no more than 10% of the urban forest should be of the same species. Further, no more than 20% of the forest should be of the same genera, and a single family should not make up more than 30% of the community's tree inventory. Following these guidelines will result in a more biologically diverse planting. Many diseases and insect pests tend to choose trees by family. Furthermore, quasi-resistant species in the same family may continue to be sources for pathogens and insects that could affect other trees in the same family. Nowhere is this phenomenon more evident than in the American chestnut blight disaster. The pathogen for this disease continues to be harbored in other trees in the same family which comprise a significant percenentage of the forest canopy. These "carrier" trees do not succumb to the disease, but they continue to spread it to young chestnut trees, and have reduced this once dominant climax community tree to a minor understory plant. This could happen in our cities as well. T. Davis Sydnor, Ph. D. and Nick E. D'Amato
|
State Urban Forest Data: Maryland
