Nyland, R.D., D.G. Ray, R.D. Yanai, R.D Briggs, L. Zhang, R.J. Cymbala, and M.J Twery. 2000. Early cohort development following even-aged reproduction method cuttings in New York northern hardwoods. Canadian Journal of Forest Research, 30:67-75.
 
 

Abstract: We described a general pattern of cohort development following two types of even-aged reproduction methods in northern hardwoods.  Three clearcut sites initially had divergent numbers of stems, because of variable amounts of advance regeneration.  By 10 years, total stem densities became quite similar across sites.  Three sites treated by shelterwood seed cutting lacked advance regeneration.  Compared with the clearcuts, seedlings became established at much higher stem densities there, and even early cohort development followed a consistent pattern.  By 20-25 years, both the clearcut and shelterwood sites supported 7600-8900 total stems/ha.  Stems >2.54 cm diameter at breast height peaked at about 6000, but by age 15 following clear-cutting, and not until age 20 after shelterwood seed cutting.  The time lag likely reflects initial differences in advance regeneration, and possibly other factors between sites.  Basal area at the clearcut sites reached 26 m2/ha within about 25 years.  At the shelterwood sites it reached 22 m2/ha by age 25.  The quadratic stand diameter increased consistently across sites and treatments.  Regression models describe changes in numbers of total stems, numbers of saplings, stand basal area, and quadratic stand diameter for each treatment.