Authors: Carmen K. Converse, Global Invasive Species Team, The Nature Conservancy
Eastern red cedar is an evergreen tree' native to eastern North America. Grown as an ornamental tree, and to a small extent for Christmas trees, it grows 5-20 m tall and up to 30 m in height. It has typically an ovoid or pyramidal crown. J. virginiana var. crebra Fern. and Grisc. has a more columnar shape. The red bark is thin (0.32 to 0.64 cm. thick) and exfoliates in long strips. Leaves of seedlings and juvenile growth are acicular; adult plants have entire, opposite scale like leaves that are tightly appressed and overlapping. The scale like leaves have an oval dorsal gland. The species is dioecous. The blue black, often glaucous fruit is a fleshy berry like cone. Each fruit usually contains one to two seeds. For further description see Rosendahl 1970, Fernald 1950.
J. virginiana grows in the eastern United States and adjacent Canada from Ontario to South Dakota, Nebraska, Kansas, eastern Texas, to north Florida, and north to Nova Scotia.
J. virginiana is very susceptible to fire destruction. It is a problem because it has rapidly invaded some grasslands and savannas mostly due to fire suppression. In areas that once burned periodically, eastern red cedar was protected from fire on dry or rocky sites lacking sufficient herbaceous fuel to carry a fire. As fire frequency decreased, eastern red cedar invaded adjacent, and apparently stable plant communities. Subsequently, individual eastern red cedars have increased in size and coverage, and stand density has increased. Large trees and dense stands shade or otherwise inhibit growth of desired herbaceous vegetation.
J. virginiana is most competitive on exposed dry sites. Plentiful habitat is provided by disturbed areas including abandoned pastures  and cultivated fields , eroded areas  and open woods thinned by timber harvest. One result of this invasion is increased seed sources.
Rapid primary invasion and establishment may be followed by secondary invasion within six or seven years. Rate of invasion and increases in stand density were examined on grazed pastures in Kansas. On heavily invaded pastures, Owensby et al. (1973) found a sigmoid population increase in nine years. In the nine years, cumulative numbers of plants on the heavily invaded pasture increased from about eight per acre (about 3/ha.) to about 180 per acre (about 73/ha).
Some natural habitats topographically and edaphically protected from fire include sandy loam covered bluffs; rocky hillsides ; shale barrens of Virginia and W. Virginia; limestone glades of Tennessee, Virginia, Missouri and Arkansas ; serpentine barrens of Pennsylvania and Maryland ; sandstone cliffs; granite outcrops; sand dunes; and estuarine swamps.
It is adapted to a wide range of environmental conditions. Annual precipitation ranges from 40.64 cm. in the Great Plains to 152.40 cm. in the southeast United States. Temperature extremes range from 40° C to 46° C. Elevations range from 1524 m. to sea level. Eastern red cedar thrives in well drained alluvial soils but also tolerates shallow limestone and sandstone soils and pH ranging from 4.7 to 7.8. It is able to grow where water is near the surface  or where soil moisture fluctuates from near saturation in the winter to extreme dryness in the summer. It is very drought tolerant. Exposure varies from north facing slopes of the plains , to south and west facing hillsides  and near level glades  and coastal plains. It is less vigorous in the shade of other trees, but can grow in the understory of deciduous species  such as oaks and hickories of the Georgia Alabama coastal plain  or cottonwoods of Great Plains riverbottoms . It also may form pure stands.
J. virginiana is cultivated for shelterbelts and windbreaks, timber, ornamentals, cedar oil and associated uses.
Eastern red cedar grows slowly and can live as long as 300 years. Plant size and growth depend mostly on soil depth and moisture availability. On well drained alluvial and upland soils greater than 24 inches (60.96 cm.) in depth, average height is 45 feet (13.72 m.) after 50 years. On soils less than twelve inches (30.48 cm.) deep, it rarely exceeds 20 (6.10 m.) to 30 feet (9.14 m.) in height and diameter growth is less than on deeper soils. In the prairie region trees less than 20 feet (6.10 m.) tall may be 110 years old.
Growth activity is more related to moisture availability than other physiological or phenological reasons. Cambial activity increases when water is available.
On rangeland, Owensby et al. (1973) found that the ground level diameter of young red cedar increased 0.27 inches (.69 cm.) and height increased 7.85 inches (19.94 cm.) for each year of growth. The range of some plant heights was as follows: six year old 24 64 in. (0.60 m.-1.63 m.), seven year old 29 75 in. (0.74-1.91 m.), and ten year old 79 90 in. (2.01-2.29 m.). Those heights are of potentially sexually mature plants in the Great Plains, and have implications for fire management.
Eastern red cedar grows better than some other species in open areas having full sunlight, low soil moisture, and occasional drought. It is least competitive in shade. In a southern Illinois study, optimal photosynthetic rates occurred in full sunlight at temperatures between 20-25° C in the summer and 15-20° in the winter. Photosynthesis continued at low soil moistures and high temperatures, and at temperatures as low as 0° C. The tightly packed branches especially of mature plants help to maintain warmer temperatures in internal foliage during the winter  and reduce dessication to maximize winter photosynthesis. In grasslands herbaceous vegetation protects red cedar seedlings from winter cooling.
J. virginiana is more drought tolerant than associated deciduous woody species in open areas because it is able to rapidly produce taproots and has an extensive fibrous root system. It also conserves moisture by stomatal closure as an early drought response, and has finely dissected leaves providing cooling during stomatal closure.
In addition to eastern red cedar's evergreen growth and efficient and opportunistic moisture use, it also affects the soil and groundcover beneath its canopy. It shades desirable herbaceous species, alters species composition  and raises surface soil pH. In Nebraska, Gehring (1983) found that groundcover of Poa pratensis L. and Carex spp. increased relative to increases in J. virginiana size. Coverage of prairie species beneath eastern red cedar decreased as tree size increased. McBain (1983) also found that tree canopy suppressed prairie species, and that soil moisture was reduced beneath trees.
Toxic substances produced in junipers may inhibit germination of some grass species. In tests of J. osteosperma (Torr.) Little, foliar extracts inhibited germination of Bouteloua gracilis HBK Lag. ex. Steud., B. curtipendula (Michx.) Torr and Agropyron desertorum (Fisch. ex. Link.) Schult..
There is no natural asexual reproduction in red cedar. It does not resprout after complete cutting or burning. Sexual maturity is reached in six  to ten years. Staminate conelets have been observed on trees four to five years old, but similar information on ovulate conelet development is unavailable. Staminate and ovulate conelets form on scale like foliage in September in North Carolina, but development is not complete until the next spring.
J. virginiana exhibits variation in form, foliage color, vigor, height growth and disease resistance. Some of this variability results from hybridization with other junipers including J. ashei Buchholz in the Ozarks, J. scopulorum Sarg. in the Great Plains, J. silicicola (Small) Bailey in Florida, and J. horizontalis Moench. in the northern extent of red cedar's distribution.
Good seed crops are produced every two or three years with light crops in the intervening years. The best seed bearing age is between 25 and 75 years, although some trees will bear seeds at 10 years and some as late as 175 years. Seeds mature in autumn and are sometimes retained on the tree until the following spring (Phillip 1910).
Most seeds are dispersed by birds, including cedar waxwings, thrushes, starlings, robins, kingbirds, downy woodpeckers, and mockingbirds. Some seeds drop to the ground to germinate beneath mother trees, or are dispersed by small mammals. Seedling density is greater near trees or along fencelines that provide perching sites, than in open sites. However, seedlings of other juniper species have been observed in open areas at long distances from these preferred perching sites.
"Most of the natural germination of eastern red cedar seed occurs in the early spring the second year after dispersal. A few seeds may germinate the first and third year. Delayed germination is caused by embryo dormancy and possibly by an impermeable seedcoat." (Folwells 1965)
There is considerable variation in stratification and scarification requirements probably due to the wide range and many genotypes of the species. These requirements for propagation can be found in Seeds of Woody Plants in the United States (1974)
Seedlings usually establish more readily on mineral soil than where a litter layer is present , but are capable of establishment in thick sod. In pastures, a critical amount of mulch may influence establishment; too much or too little prevents germination.
"Eastern red cedar seedlings withstand drought rather well because of their deep, penetrating taproot and relatively small leaf surface. During the first year seedlings do not produce much top growth, but they produce a long fibrous root system. Seedlings will often survive on arid sites, but their growth is slow.
The species is rather shade intolerant in the seedling stage. In the southern Piedmont area, red cedar seedlings under open canopy stands survived better than under closed canopy stands. A study indicated that the height growth responses of 1-0 seedlings (one year old, not transplanted) in full sunlight were the same. Seedling growth was stunted when grown in one tenth sunlight. It is more sensitive to flooding than loblolly pine."  Mice, rabbits, livestock  and deer  may damage seedlings. Increased stocking rates of cattle on Kansas pastures generally decrease red cedar invasion. In one study, invasion decreased especially when cattle grazed during May through October. Seedling survival is usually high following transplanting.
- Lack of fire
- Human activities increase habitat occurrences
- Many genotypes and hence wide environmental adaptability
- Plant longevity, sexual maturity in 6 to 10 years, long reproductive phase
- Efficient seed dispersal, germination and seedling vigor
- Opportunistic moisture use resulting in drought tolerance
- Evergreen growth and tolerance of temperature extremes
- Large plant size which results in shading, high moisture use, soil pH changes, higher fire tolerance, possible allelopathic effects
Active management is required to reduce populations, and to prevent invasion by maintaining vigor of grassland species.
The effectiveness of burning to control eastern red cedar is related to tree height, crown density, stand density, amount of herbaceous fuel and fire weather conditions.
Spring burns (March through May) usually kill trees up to about one meter tall ( Buehring 1971). Larger trees up to 20 feet (6.1 m.) occasionally are killed in some fires (Ownesby et al. 1973), or under drier, windier, and less humid conditions. In a Missouri burn in April, Kucera et al. (1963) found that 93% of all red cedar were killed; the largest tree killed was 10 feet (3.05 m.) tall. Air temperature was 63° F (17.2° C) and humidity was 21%. After another 'cooler' burn on March 31, at 53° F (11.7° C) and 43% humidity, crowns of larger plants (1.52 to 8.89 cm. in diameter at 15.24 cm. above ground) remained green. In Oklahoma, Dalrymple (1969) found complete control of J. ashei seedlings less than 2 feet (0.61 m.), 77% mortality of trees 2 6 feet (0.61 1.83 m.) and 27% mortality of trees greater than 6 feet (1.8 m.).
In a Missouri burn, large tree mortality depended on amount of herbaceous fuel and density of crowns. Trees having crowns with sparse foliage exhibited 90% mortality. Trees having larger crowns with dense foliage showed 35% mortality. Light crowned trees had more foliage beneath them than did densely crowned trees. Temperatures the day of the burn ranged from 28-60° F ( 2.2 to 15.5° C), the lowest relative humidity was 26%, and winds averaged 4.7 mph (7.6 kms.per hour).
For control of large trees, herbaceous fuel levels must be adequate to carry a fire. When burning large red cedar, Launchbaugh and Owensby (1978) allow for 3,3.71-4,494 kg/ha of herbaceous fuel. A 30 to 61 meter firelane is burned out when grasses are moist. After that burn is extinguished, a headfire is set when winds are about 24 km/hour and relative humidity is about 40%.
Sometimes fire will not easily carry through dense stands of red cedar, requiring additional controls such as dozing or windrowing. In Texas, a 250 ha. area of dense J. ashei was burned by a crown fire started by igniting windrows of dried juniper adjacent to the area to be burned. The authors determined from this study that such areas would optimally burn when wind speeds exceed 16 km/hr, canopy cover is greater than 35%, relative humidity is between 20-40 %, air temperature is 2 to 32° C and leaf moisture is below 60%.
Volatile fuels found in J. virginiana are explosive and can produce firebrands. Firebrands during a moist spring burn of J. ashei created spot fires 60 to 90 feet (18.3 to 27.4 m.) from piles of junipers. Under extremely dry conditions (81° F, 14% relative humidity, 10 to 15 mph winds = 27° C, 16.1 to 24.1 km/hr) spot fires occurred 800 to 1000 feet (243.8 m. to 304.8 m.) from the fire edge.
A single cut close to the ground level that removes all green foliage usually will kill red cedar. In one study, plants cut having basal diameters between 0.25 inches (0.64 cm) and 0.75 inches (1.91 cm.) showed 20% resprouting sixteen months after cutting. No regrowth occurred on plants having basal diameter larger than 0.75 inches (1.91 cm). Plants having basal diameters of 0.5 inch (1.27 cm) to 1.25 inches (3.18 cm) mowed 6 inches above ground showed 22% resprouting sixteen months after mowing. This regrowth is attributed to the presence of buds within six inches of ground level.
Most herbicides are ineffective or erratic in control of red cedar. The best results from herbicidal control are as follows:
1. Tree injection
Picloram as a potassium salt injected into trees in winter, summer and spring (Oklahoma) at rates of 1 and 3 ml. per inch (2.54 cm.) dbh (diameter breast height) killed red cedar after 14 months. In an Arkansas study, picloram in an aqueous solution (1:5) injected in June provided 83% kill by the following December.
2. Soil application
Application of 10% granular picloram in August (Oklahoma) at least 3 and 6 teaspoons per inch dbh provided 90% and 70% control respectively after 13 months. In Kansas, fenuro, picloram, and karbutilate applied as granules to the soil in April at 1 to 2 tablespoons per inch basal diameter showed 70 to 100% control after 23 months.
3. Foliar and stem sprays
Sprays giving greater than 80% kill on trees 2 to 4 feet (0.6 to 1.2 m.) tall and 7 to 8 feet (2.13 to 2.44 m.) high included paraquat at 1 and 2 lbs./acre (1.12 and 2.24 kgs./ha) + 0.5% suffactant; dicamba at 3 and 6 lb./A (3.36 and 6.72 kg./ha) and dicamba at 2 lbs./A (2.24 kgs./ha) + 2-4-5T ester at 4 lbs./A (4.48 kgs./ha); 2-4-D + dichloropropal at 4 lbs./A (4.48 kgs./ha) each or 8 lbs./A (8.96 kgs./ha) each; and AMS at 50 and 75 lb./100 gal. (.06 and .09 kg./l) spray (Buehring et al. - 1971 from Forestry Abstracts 24(6) 1973).
4. Basal application
Hexazinone applied as an undiluted liquid in July in Virginia at 4 and 8 ml./2 inches (5.08 cm.) of basal stem diameter killed red cedar trees having basal stem diameter less than one inch (2.54 cm.) to 7 inches (17.78 cm).
Leaf blight (Cercospora sequoiae Ell. and Ev. var. juniperi) has killed 15 to 20 year old eastern red cedar.
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- ↑ Collingwood, G.H. 1938. Eastern red cedar, Juniperus virginiana L. Amer. Forests 44:30-31. 2.0 2.1 2.2 2.3
- ↑ Van Haverbeke, D.F.; Read, R.A. 1976. Genetics of eastern red cedar. U.S. Dept. Agric., Forest Service Research Paper WO 32. 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12
- Fernald, M.L. 1950. Gray's manual of botany. 8th ed. New York: D.Van Nostrand Co. 1632 p.
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- Bray, Roger. 1960. The composition of savanna vegetation in Wisconsin Ecology 41(4):721-732.
- ↑ Arend, J.L. 1950. Influence of fire and soil in distribution of eastern red cedar in the Ozarks. J. Forestry 48:129-130. 8.0 8.1 8.2 8.3 8.4 8.5 8.6
- ↑ Beilmann, A.P.; Brenner, L.G. 1951. The recent intrusion of forests in the Ozarks. Missouri Botanical Gardens Ann. 38:261-282. 9.0 9.1
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- ↑ Ormsbee, P.; Bazzaz, F.A.; Boggess,W.R. 1976. Physiological ecology of Juniperus virginiana in old fields. Oecologia (Berl.) 23:75-82. 11.0 11.1 11.2 11.3 11.4
- ↑ McBain, D.K. 1983. Influence of eastern red cedar (Juniperus virginiana L.) on soil properties and vegetative composition of a sand prairie in southwestern Wisconsin. Thesis. (from abstract). 12.0 12.1 12.2 12.3
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- ↑ Hinckley, T.M.; Dougherty, P.M.; Lassoie, J.P.; Roberts, J.E.; Teskey, R.O. 1979. A severe drought impact on tree growth, phenology, net photosynthetic rate and water relations. Amer. Midland Nat. 102(2):30-316. 23.0 23.1
- ↑ Albertson, F.W. 1940. Studies of native red cedar in west central Kansas. Trans. Kansas Acad. Sci. 43:85-96. 24.0 24.1 24.2
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- ↑ Fowells, H.A.; compiler. 1965. Silvics of Forest Trees of the United States. U.S. Dept. Agric. Forest Service. Agriculture Handbook No. 271. 762 p. 28.0 28.1 28.2 28.3
- ↑ Gehring, J.L. 1983. Vegetational changes under isolated Juniperus virginiana in an eastern Nebraska bluestem prairie. Univ. Nebraska Omaha; Thesis. (from abstract). 29.0 29.1 29.2
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- ↑ Phillips, F.J. 1910. The dissemination of junipers by birds. Forestry Quarterly 8:60-73. 33.0 33.1
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- U.S. Department of Agric., Forest Service. 1974. Seeds of woody plants in the United States. U.S. Dept. Agric. Handbook 450. 883 p.
- ↑ Parker, J. 1952. Establishment of eastern red cedar by direct seeding. J. Forestry 50:914-917. 36.0 36.1
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- Van Deusen, J.L. 1979. Eastern red cedar seed sources recommended for North Dakota sites. U.S. Dpt. Agric., Forest Service. Rocky Mountain For. and Exp. Station Research Note RM 371:1-5.
- Munns, E.N.; Stoeckeler, J.H. 1946. How are the Great Plains shelter belts? J. Forestry 44(4):237-257.
- Arend, J.L. 1945. An early eastern red cedar plantation in Arkansas. J. Forestry 45:358-360.
- ↑ Wink, R.L.; Wright, H.A. 1973 Effects of fire on an Ashe juniper community. J. Range Management 26(5):326-329. 43.0 43.1
- Allred, B.W. 1949. Distribution and control of several woody plants in Texas and Oklahoma. J. Range Management 2:17-29.
- ↑ Kucera, C.L.; Ehrenreich, J.H.; Brown, Carl. 1963. Some effects of fire on tree species in Missouri prairie. Iowa State J. Sci. 38(3):17-185. 45.0 45.1 45.2
- ↑ Launchbaugh, J.L.; Owensby, C.E. 1978. Kansas rangelands: their management based on a half century of research. Kansas Agric. Exp. Station Bull. 622. 56 p. 46.0 46.1
- Wright, H.A.; Bailey, A.W. 1980. Fire ecology and prescribed burning in the great plains a research review. U.S. Dpt. Agric., Forest Service General Technical Report. INT 77.
- ↑ Bryant, F.C.; Launchbaugh, G.K.; Koerth, B.H. 1983. Controlling mature Ashe juniper in Texas with crown fires. J. Range Management 36(2):165-168. 48.0 48.1
- Wright, H.A.; Britton, C.M.; Wink, R.L.; Beckham, Bob. 1972. A progress report on techniques to burn dozed juniper. Proc. Tall Timbers Fire Ecol. Conf. 12:169-174.
- ↑ Buehring, N.; Santelmann, P.W.; Elwell, H.M. 1971. Responses of eastern red cedar to various control procedures. J. Range Management 24:378-38. 50.0 50.1 50.2 50.3
- Toney, Thomas E. 1983 Nov. 29. Prairie biologist, Missouri Dpt. Conservation. Telephone to C.K. Converse, The Nature Conservancy Regional Office, Minneapolis, MN.
- ↑ Scifres, C.J. 1980. Brush Management. College Station, TX.: Texas A&M Univ. Press. 360 p. 52.0 52.1
- Johnsen, T.N. 1979. Herbicidal control of junipers. Proc. Western Soc Weed Sci. 32:79.
- Voeller, J.E.; Holt,H.A. 1973. Continued evaluation of the hypohachet for woody species control. Proc. 26th Ann. Meeting Southern Weed Sci. Soc. 354-360.
- Buehring, N.; Santlemann, P.W.; Elwell, H.M. 1973. Responses of eastern red cedar to various control procedures. Proc. 23rd Ann. Meeting So. Weed Sci. Soc. 1970. From Forestry Abstracts 34 (abstract no. 3467).
- Rosendahl, C.O. 1955. Trees and shrubs of the upper Midwest. Minneapolis,MN.: Univ. Minnesota Press. 411 p