A Healthy Obsession with Oak

Originally posted January 2011

Most have probably seen Jim Perdue's commercials in recent years, where the poultry CEO touts a "healthy obsession with chicken".  There were times when state foresters have been accused of the same level of obsession with managing and regenerating oak species in our Connecticut state forests, such as Nassahegon State Forest in Burlington.  Why does it seem foresters are primarily motivated to manage for oak, when our major objective is managing for a diversity of forest types and age classes?

 

We have even been asked why we are trying to create a monoculture of oak in our forests.

First of all, the easy answer is that oak is not simple to regenerate compared to some native trees, so any effort toward that end has a risk of less than desirable results.  We could not create a monoculture if we wanted to.  The successful establishment and, more importantly, survival and graduation to the forest overstory of oak is usually a multiple-phase process for foresters that requires follow-up attention.  On the other hand, one really does not have to exert effort to regenerate black birch, red maple, or beech, so management specific to these species is not as necessary.  In other words, management of oak to ensure continued survival of oak forests in Connecticut requires a lot of attention for a little success.  Birch, maple, beech, on the other hand, more accurately demands no attention for a lot of success.  

 

Why is oak so important at all?  Most of Connecticut is dominated by native oak forests.  Before Governor Rell left office, she announced that wood products are now being included in the "Connecticut Grown" program, a label associated with other agricultural products since the mid-1980s.  Connecticut has long been a source of high quality, locally-grown and renewable hardwood timber, especially red oak logs that have been sought worldwide.  

 

From a local ecosystem perspective, oak is very important because acorns provide an essential source of protein for many wildlife species.  White-tailed deer, black bear, and turkeys (among other species) depend on acorns as a fall food source needed for packing on the pounds and winter fat layers needed to survive our Connecticut winters.  Wildlife is so dependent on the hard mast that success of some wildlife species year to year can be predicted based on the size of fall acorn crops.  Oaks also host the most abundant and diverse array of moths and caterpillars, which in turn attracts a great abundance and diversity of birds.

 

The challenge in regenerating and maintaining oak lies in its disturbance-dependent nature.  Oak seedlings appreciate a lot of full sunlight and historically, many of our oak forests today were originally established from an active landscape disturbance regime:  American chestnut, a once dominant forest tree in Connecticut, died from the introduced chestnut blight disease by early in the 20th Century.  This widespread mortality created canopy openings and encouraged salvage logging that provided an opportunity for oak to exploit.  Until that point, oak was generally regarded as secondary in importance for both its timber and wildlife benefits.  After the passing of chestnut, oak immediately began to fill the niche.  

 

Other disturbances were also working in favor of oak in the latter part of the 19th Century and early 20th Century.  Charcoal production was very common in Connecticut until after World War I, and this entailed the repeated clearcut of many forests, a practice very conducive to oak regeneration.  Forest fires were also far more serious in those days, and although it is not heard of today, a century ago fires could rage out of control for hundreds or even thousands of acres in Connecticut.  Fire also assists in the regeneration of oak and effectively reduces competition by other tree species.  (Before European settlers, Native Americans used fire to manage vegetation and this benefitted oak for centuries.)  

As a result of the above period of disturbances and land use changes, most of our oak forests

established and thrived, and many of our oaks today are between about 90 and 120 years old.

 

Unfortunately, the trend in this century is toward a continuous loss of oak forest to other types, specifically the aforementioned red maple and black birch.  Although those species naturally have an important place in a native diverse ecosystem, as well, they have historically not been dominant, and do not provide essential hard mast and promote the same level of insect and bird diversity of oak forests.  

Why is oak expected to diminish?  Simply put, the same disturbances that kept oak here no longer prevail.  Modern fire control has eliminated landscape level fire disturbances.  Clearcutting and other heavy harvesting practices are often viewed as undesirable by private landowners in favor of lighter, more "selective" cutting that favors shade tolerant species such as birch and maple.  Aesthetics is winning, as is the chief competition of oak.  Also significant is the impact of deer in Connecticut.  Oak seedlings are desired browse by deer, whereas birch and maple are not.  So a high deer population in our state is also having a strong influence on the composition of our future forests.  

 

Foresters on state land are trying to do their part by managing for oak where natural seed sources and growing site quality favor oak.  Oak management usually involves a 2 or 3 phase "shelterwood" type harvest system that favors establishment of the shade-intolerant oak seedlings and then provides further periods of disturbance that help nurture a new oak forest and reduce competition (oak seedlings are slow growing for the first few years of life when compared to competitors).  Sometimes, a controlled burn (prescribed fire) may be used to increase the success rate from the shelterwood cuts. This type of prescription may be used in some areas of Nassahegon State Forest in the years ahead as it has been in the past.  

 

Rather than "obsession", I prefer to call area foresters' interest in oak forests a healthy "attentiveness" to inevitable changes in store for our state in the years ahead.  The reason I find forestry such a fascinating profession is that it not only scrutinizes modern trends but delves deep into local and regional history to determine a management strategy, not only for a few years ahead but for decades, even a century into the future, long after professionals of today are no longer here. This commitment to contributing to a better future world, and to a cause that goes beyond our own longevity, is one of the original reasons this forester was attracted to the profession - not just that I enjoy being in the woods!

 

 

For questions on forest management discussed in this writing or any other related matter, just Ask Dave!  Or "tune in" for more next time!  You are also encouraged to visit our DEP website at www.ct.gov/dep, and explore our Forestry page for more information.  

Special thanks in this edition to fellow DEP forester Emery Gluck, for his own insights and writings used in development of this narrative.

 

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