Reaction to Competition
Eastern redcedar has been classified as intolerant to very intolerant of shade (11,30), but trees that have lived for decades beneath a full canopy of hardwoods or pines on medium- to low-quality sites have been observed. Apparently, eastern redcedar has an inherent low capacity for water loss and the ability to sustain stomatal opening at low water potentials, which help the species adapt to dry environments (4). Eastern redcedar can also conduct photosynthesis when overstory hardwoods are leafless and perhaps even reduces its light requirements for photosynthesis by adjusting to shaded conditions (17,24). Eastern redcedar is a pioneer species on surface-mined areas, old fields, or pastures that are protected from fire; and it is the primary natural reproduction in many shelterbelts. However, stands formed through invasion of old fields may deteriorate at around 60 years of age as hardwoods or other competing species become established. Eastern redcedar grows well and faster than associated species because it is sun-adapted, drought-resistant, and has a long growing season. On most sites, eastern redcedar is temporary and is eventually replaced by more tolerant hardwoods and pines. However, clusters of eastern redcedar established beneath hardwoods have survived longer than the competing hardwood trees, possibly due to an allelopathic effect, or the species may be a better competitor for water and nutrients (34). The species is more permanent on poor sites having thin, rocky soils, such as the glades of the Ozarks of Missouri and Arkansas and the Nashville Basin in central Tennessee. Eastern redcedar invasion of pastures is a problem on areas converted from poor hardwood sites in the Ozarks and western areas of its range (9,31), and the species is likely to persist for a long time if left to grow (7).
Eastern redcedar should be managed in even-aged stands, judging from studies conducted in northern Arkansas (11). Good growth rates can be maintained by controlling competition and stand densities.
Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965). U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.