Natural Disturbances

Diverse Forests are Better

How to reduce risk in the face of catastrophic disturbance? 

 

Diversity is a good thing when it comes to the ability of the forest to resist damage or rebound quickly in the wake of a hurricane or major insect infestation.  However, at present, our watershed forests are not as diverse in age or structure as they could be. 

 

As a result of decades of over-browsing by deer, previous land use patterns, and the legacy of the 1938 hurricane, only 10% of the forest is less than 15 years old, and the rest is mostly even aged, and 70 or more years old.  Why are age and height important?  A study of damage to the forest from the 1938 hurricane found a general trend of increasing damage with age.  Depending on the species, 10 year-old stands were damaged at the rate of 0 to 15%, whereas 30 year-old stands were damaged at rates ranging from near zero to 100%.  At age 70, the minimum damage rate was 30%.

 

That is why DWSP forest managers are following a publicly reviewed management plan that will gradually lead to a well balanced mix of young, mid-aged, and older trees (as well as a variety of species) well distributed across the watershed.