Even- vs. Uneven-aged Reproduction Methods

photo by Chris Demers

Even- and uneven-aged reproduction methods have several advantages and disadvantages associated with them. When choosing a reproduction method it is first necessary to determine:  

  • what you seek
  • what species and stand conditions will satisfy your objectives
  • the type of stand you want, given the species sought or uses intended
  • what biological or ecological limitations you will face in achieving the desired results
  • the constraints posed by the physical environment
  • the costs involved and what you are willing to pay
EVEN-AGED UNEVEN-AGED
Advantages Disadvantages Advantages Disadvantages
Allows almost complete control over stand establishment Supply of seed or seedlings must come from outside of the stand to be established, unless shelterwood or seed tree reproduction methods are employed Seed supply comes from the residual stand, ease and certainty of natural regeneration Control over stand establishment is difficult to achieve
High levels of direct solar radiation Seedlings are highly exposed to the elements  Regeneration is more sheltered from the elements Lower levels of direct solar radiation 
Less root competition in the regenerated stand Higher potential for damaging erosion to occur Lower potential for damaging erosion to occur More root competition in the residual stand
Suitable for regenerating shade-intolerant tree species. Shade-tolerant species may be overly exposed Suitable for regenerating shade-tolerant tree species  May not be suitable for regenerating shade-intolerant tree species
Logging and administrative costs relatively low The forest is significantly changed after cutting The forest is not significantly changed after cutting High logging and administrative costs; low volumes
Enables use of genetic improvements, when planted Usually less biologically diverse, particularly young stands Usually more biologically diverse  Difficult to use genetic improvements
Usually not as costly to invest in tending of small trees Less suitable for small ownerships More suitable for small ownerships Usually costly to invest in tending of small trees (on large ownerships)
Relatively simple to achieve a balanced, sustained yield of forest products Income only at final harvest or thinnings Growth capacity of site can be converted to revenue at short intervals  Difficult to achieve a balanced, sustained yield of forest products
More adaptable to reclamation of nonproductive sites Costly site preparation, including use of pesticides and heavy equipment, is usually necessary Site preparation is usually unnecessary Less adaptable to reclamation of nonproductive sites
Uniform growth rates and tree size Usually less aesthetically pleasing, depending on species composition Usually more aesthetically pleasing Growth rates and tree size variable
  Higher risk of disease, insect problems, and wildfire Lower risk of disease, insect problems, and wildfire