Eastern redcedar grows on a wide variety of soils, ranging from dry rock  outcrops to wet swampy land (15). The most common soils fall within the  soil orders Mollisols and Ultisols. No attempt will be made here to  describe all of them. Like most species, eastern redcedar grows best on  deep, moist, well-drained alluvial sites, where its height may reach 17 to  18 m (55 to 60 ft) in 50 years. On the better sites, however, hardwood  competition is so severe that the species rarely becomes dominant. Eastern  redcedar also grows well on deep, upland soils, particularly abandoned  farmland. A 0.4-hectare (1-acre) plantation established in Arkansas from  wildlings, with spacing of 1.8 by 1.8 m (6 by 6 ft), yielded a basal area  of 37.4 m²/ha (163 ft²/acre) and an estimated 196 m³/ha  (2,800 ft³/acre) of merchantable volume in 44 years (11).

    The species is frequently associated with areas commonly called glades,  characterized by thin rocky soils and intermittent rock outcrops; soil  depth is difficult to determine because soil rock content and depth of  rock fissures vary (11,16). Soils on the poorest glade sites are less than  30 cm (12 in) deep, medium sites are usually less than 61 cm (24 in) deep  and have large crevices, and good sites have deeper soil. Arend and  Collins (3) developed the site classification system shown in table 1. 

    Table 1- Site classes for natural stands of eastern  redcedar in northern Arkansas            Site Class              Item  I  II  III  IV            Soil character  alluvial  upland  upland  upland      Soil depth, cm  61+  61+  30 to 58  less than 30      Soil depth, in  24+  24+  12 to 23  less than 12      Site index¹              Open stand, m  16.8  13.7  10.7    7.6      Open stand, ft  55     45     35     25         Closed stand, m  18.3  15.2  12.2    9.1      Closed stand, ft  60     50     40     30         ¹Adjusted to  base age 50 years.        Eastern redcedar grows on soils that vary widely in acidity. Soils found  in natural stands range in pH value from 4.7 to 7.8. Although the species  will grow on sites that are slightly alkaline, it is not particularly  tolerant to higher pH levels. Eastern redcedar is, in fact, among the  least alkali-tolerant of drought-hardy trees and shrubs. Soils in eastern  redcedar stands tend to become neutral or slightly alkaline because the  high calcium content of the tree's foliage can change the pH of the  surface soil in a relatively short time. This condition also increases  earthworm activity, with an increase in incorporation of organic matter, a  lower volume weight, and an increase in pore volume and infiltration rate  (11,15).

    Eastern redcedar grows on ridgetops, varying slopes, and flat land and  is frequently found on dry, exposed sites and abandoned fields. This  aspect also influences eastern redcedar development. In the western part  of its range, the species may be found on north-facing slopes and along  streambanks where there is some protection from high temperatures and  drought. Although the most desirable elevation is not clearly delineated,  eastern redcedar is found most often growing between 30 m (100 ft) and  1070 m (3,500 ft). It is notably absent below the 30 m (100 ft) elevation  zone in the southern and eastern parts of the species range (15,27).