Research at N. C. State University related to regeneration of Atlantic White Cedar (AWC) and Baldcypress.
August 2002
L. Eric Hinesley,
Dept. of Horticultural Science, N. C. State University, Raleigh, NC 27695-7609
I. INTRODUCTION - ATLANTIC WHITE CEDAR
Atlantic white cedar (Chamaecyparis thyoides (L.) B.S.P.) is an evergreen conifer that grows in fresh water swamps and bogs along a narrow coastal belt from southern Maine to northern Florida and west to southern Mississippi (Laderman 1989). The wood is lightweight, fragrant, straight-grained, easily machined, does not crack or check, and extremely resistant to decay. All these traits made it highly prized for boats, siding, and shingling in the past. Historically, white cedar was the most valuable tree in the Albemarle Peninsula in the coastal plain of eastern North Carolina (Krinbill 1956). It had a stumpage value 2X to 5X greater than other species, and special effort was made to accurately locate all stands so they could be reached with minimum construction of railroad spurs. In addition, severe fires created an economic windfall for lumbermen who would go into the swamps and harvest the abundant supply of sound logs, previously embedded in the peat matrix, which were exposed after the peat had been consumed by fire (Ruffin 1861, Hall and Maxwell 1911).
The acreage of AWC today is probably <= 5% of the original (Davis et al. 1997, Frost 1987, Kuser and Zimmermann 1995, Lilly 1981). In the late 19th century, the greatest assemblage of AWC was in the Great Dismal Swamp, with large acreage also in Dare, Hyde, Tyrrell and Washington Counties (Ashe 1894). Ashe (1894) estimated 200,000 acres of AWC in eastern North Carolina, with about 40,000 acres in the peninsula and 60,000 acres in Great Dismal Swamp. An intense period of logging occurred in the Albemarle-Pamlico peninsula between 1885 and 1920, mostly by John L. Roper Lumber Co. and Richmond Cedar Works. In 1937 there was an estimated 82,000 acres with AWC, either pure or in mixed stands, in the Northeastern Coastal Plain of North Carolina, including the Great Dismal Swamp (Roberts and Cruikshank 1941). They mentioned no AWC in Washington County, but noted commercial stands in Tyrrell and Dare Counties. In 1990, the combined volume of AWC sawtimber ( ~ 10 inches in diameter) in the northern and southern Coastal Plain of North Carolina was ~210 million board feet (Johnson 1990, Thompson 1990). Less than 10,000 acres of AWC still remain in North Carolina, with more than half in Dare Co. (Davis et al. 1997). The precipitous decline in acreage of AWC resulted not only from logging, but also from uncontrolled wildfires and widespread ditching and drainage of peatlands for agricultural purposes.
Ashe (1894) concluded that the existing rate of exploitation of forests in eastern North Carolina would exhaust the resource within 20 years. That prophesy never materialized; people realized the need to save the resource, and took steps to do that. Today, Ashe's concerns can be echoed for AWC, which is making its last stand in the eastern end of the Albemarle-Pamlico peninsula and the Great Dismal Swamp.
Several bulletins and books have been written about AWC (Ackerman 1923, Korstian 1924, Korstian and Brush 1932, Little 1950; Laderman 1987, 1989). In general, there is a substantial body of older literature concerning AWC. There has been a strong interest in AWC in the last decade, as reflected by several workshops and symposia (Christopher Newport University 1997, N. C. Forest Service 1995, Stockton College 1996; Christopher Newport University, 1997 and 2000), review articles (Kuser and Zimmermann 1995, Laderman 1989, Phillips et al. 1998), and a variety of research publications. Research programs for AWC are currently underway on the larger national forests and wildlife refuges located on peat soils in eastern North Carolina, including PLNWR, Lake Mattamuskeet NWR, Alligator River NWR, and Croatan NF.
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Long ago, people on the lower Coastal Plain of North Carolina recognized the association between tree cover and land quality. The best land for agriculture supported gum/cypress forests, and was underlain by clay, or sandy clay (Ashe 1894, Ruffin 1861). In the late 1800's, most good cypress land in the Pamilico Peninsula had already been drained and converted to agriculture (Ashe 1894). Smaller areas of peat (histosols) largely disappeared in response to drainage, fire, and tillage (Dolman and Buol 1967, Lilly 1981, Ruffin 1861). Although most land suitable for farming - mineral soils or shallow organic soils - is still in private ownership, there are inclusions of such soils within the National Wildlife Refuge System.
Early writers also knew that many Atlantic white cedar (AWC) sites -- characterized by deep peat, or peat over sandy soil -- had little value for agriculture (Ruffin 1861; Pinchot and Ashe 1897), and should be retained for production of AWC. Roberts and Cruikshank (1940) made similar observations concerning pond pine pocosins. Hall and Maxwell (1911) agreed with earlier authors, but correctly speculated that much of the land would be drained for agriculture in the early 20th century. The experience of Norfolk & Southern Land Development Co., Atlantic Farms, and First Colony Farms (FCF) proved the veracity of the earlier observations about site quality.
AWC will not regenerate under flooded conditions. It normally gains footing on sites just above the water table. Like red maple (Acer rubrum), it is moderately tolerant of flooding (Hook 1984). AWC grows best where the water table is only a few inches below the surface during the growing season (Korstian and Brush 1932, Ackerman 1932, Little 1950). AWC sites are normally "drier" than cypress/gum sites (Whitehead 1972). AWC occupies a narrow hydrologic position toward the wet end of the moisture gradient, and intermediate between that of deciduous swamp forest and evergreen pocosin (Frost 1987).
Young seedlings easily establish beneath the shade of an overstory, but require more intense sunlight by the third year to continue normal development. Hardwoods such as red maple are more shade tolerant, an important reason why they eventually take over AWC stands that are undisturbed or selectively logged (Roman et al 1990). It is fairly common for a remarkably dense vegetation to claim a site after cedar is logged (Phillips et al. 1998, Whitehead 1972).
AWC can occur on a wide variety of sites, but is usually found on peat overlying sandy soil, or in sandy creek bottoms with soils high in organic matter (Korstian 1924). It shuns alluvial sites, where cypress and gum tend to dominate.
AWC is susceptible to windthrow. Typical of many pioneers, it often grows in dense, even-age stands, and has a long bole, narrow crown, and shallow root system. With these characteristics, trees are easily windthrown in the soft peat where they usually grow, especially when a dense stand is suddenly exposed to wind from the side, as after a logging operation in adjoining stands. Storms and hurricanes have played a major role in destroying or altering forest stands in eastern North Carolina. In the last two centuries, for example, hurricanes have struck the South Carolina coast once every 7 years (Conner 1998). If seed is available, either within the peat or from surrounding trees, AWC stands can regenerate following destruction. baldcypress is rarely windthrown, even by the fiercest storms (Matoon 1915). More than 200 years ago, a German naturalist noted that AWC south of Albemarle Sound (below Edenton) could reach 60-100 ft in height and 12-15 ft in circumference at the base, but only on fertile swamp soils where trees were protected at the sides by other trees (Morrison 1911).
Available information is helpful in determining where and how to establish AWC, and how to maintain and perpetuate it, once there. Even among people who spent many years studying AWC, there is not total agreement on all issues. However, certain common themes seem to recur, particularly the role of fire.
In the great peatlands, fire frequency and depth of peat are two master factors determining the distribution and structure of many plant communities (Frost 1995). Other factors such as soil series, hydrology, fertility gradients, source and chemistry of water, and direction of water movement through the system are also important. Normally, no single factor is the sole determinant. There is a complex interaction among factors (Frost 1995, Otte 1981, Weakeley and Schafale 1991), resulting in broad generalizations such as the following:
"Forests dominated by AWC occupy the same sites as pocosins in a temporarily shifting mosaic determined by catastrophic fire events. At the landscape level, and over a period of centuries, wetlands dominated by AWC cannot be distinguished from pocosins. They have the same set of characteristic species as many pocosin types, and often have gradational boundaries to pocosins (Weakley and Schafale 1991)."
The most crucial factor in determining the presence of swamp forest, as opposed to other pocosin communities of lower stature, is the origin of water in the system, and its direction of movement (Daniel 1981, Otte 1981). This idea helps explain the distribution of various plant communities in wetlands of eastern North Carolina, and the failure of swamp forests in some locations to convert to pocosin vegetation of less stature (Daniel 1981, Lynch and Peacock 1982a). Water in domed pocosins (example: area south of Phelps Lake) originates only from rain because the area is higher than the surrounding countryside, causing water to flow outward. These systems are nutritionally sterile (ombrotrophic). Other pocosins receive water from surrounding uplands, overland flow, or groundwater seepage; consequently, are more fertile and thus more likely to support forests (Daniel 1981, Daniels et al. 1984, Lynch and Peacock 1982a).
Swamp forests often occur in peat-dominated wetlands adjacent to higher ground. Water runs off the high ground into the swamp. Consequently, swamp forests have a higher mineral content in the peat, largely as clay, which is carried into the wetland as sediment. In addition, runoff also carries nutrients that would not be present in rainwater. Enhanced fertility helps support swamp forests. The presence of considerable AWC in the swamps adjoining Alligator River is probably related more to the nature of the flooding regime than to depth of peat, soil series, or fire history (Lynch and Peacock 1982a, Moore and Laderman 1989). These AWC forests occur in non-alluvial swamps where there is neither heavy sediment load nor high overbank flows, as in brown-water river flood plains where cypress and water tupelo would be more common.
The
distribution of AWC in Florida also confirms the importance of water
source and movement in determining the occurrence of various plant
communities:
In Refuge land in eastern N. C., the same principle is Illustrated in the vast Upper Alligator River Pocosin in southeastern Tyrrell County (McDonald and Ash 1981), the drainage basin for Northwest Fork, Juniper Creek and Southwest Forks of Alligator River. A 1960 WestVaco map shows AWC on peat about 6 feet thick north and west of the intersection of Middle Rd and Seagoing Road (Tyrrell Co, upper reaches of Northwest Fork) (Scotia Quadrangle, p. 77). Backwater swamps like this tend to be wet, but not severely flooded, and would receive nutrients and water from surrounding land, thus explaining why peat of such depth might support swamp forests. This does appear to be the situation: overland flow moves into the area from the west, south, and north (Heath 1975, Soil Conservation Service 1994). The area around Frying Pan Lake also illustrates this principle: water moves generally eastward into the areas where AWC was historically abundant.
The distribution and occurrence of white cedar is affected by the frequency and intensity of fires and other disturbances. Results are often unpredictable, resulting in conversion to hardwood swamps rather than AWC. Where possible, disturbance must be carefully managed or controlled in order to encourage, not deter, cedar regeneration (Roman et al 1990).
Fire can easily destroy AWC, but, if not too severe, also creates conditions that favor establishment of this pioneer species if a seed source is present. However, a second fire within 10-20 years will eliminate it and change the composition of the vegetation, usually more toward pond pine (Korstian 1924, Little 1950). In another scenario, mild fires often result in conversion to hardwoods such as maple as a result of sprouting from stumps not killed by the fire (Roman et al. 1990).
AWC is sensitive to fire, but without fire it gives way to other species (Christenson 1981, Frost 1987, Korstian 1924, Little 1950, Motzkin et al. 1992). AWC forests can be regarded as "special fire serclimaxes, the special conditions occurring so infrequently . . . as to limit the extent to which these forests have appeared" (Wells 1942). AWC forests "are the product of a low frequency, relatively high intensity fire regime which is probably related to their marginally moist soil conditions. Too frequent fire, either prescribed or the result of lower water tables, will convert such areas to shrub bogs. Infrequent fires result in decreased importance of white cedar and pine"; (Christensen 1981).
Quoting Frost (1987): "The known longevity of AWC and its absence from regions which originally burned frequently suggest that AWC was limited to areas having catastrophic fire return intervals ranging from about 25 to 250 years. Repeated logging in the absence of fire leads to step-wise reduction in area and loss of cedar habitat to deciduous swamp forest, with eventual extirpation of the species. This effect, along with widespread hydrologic changes associated with ditching, seems adequate to explain virtually all known cases of white cedar displacement in the Carolinas. It requires periodic catastrophic fire, but with a medium to long fire return interval".
The most extensive development of AWC forests occurred on medium to deep peat soils with fire intervals of 100 - 300 years (Frost 1995). One hundred years allows stands to mature and accumulate an extensive seed bank in the upper few inches of peat. Three hundred years is the approximate longevity of AWC, but at that age, too few trees still remain on the site to maintain a good seed bank or prevent succession to other species (Frost 1995). AWC can occur with fire intervals of 50-100 years; sometimes, small patches might appear with fire intervals of 13 to 25 years (Frost 1995). In Massachusetts, "the burning cycle was 100-200 years before Europeans came. In the 600 - 800 years before establishment of the current mature stand, AWC did not persist for more than 100 200 years without stand regenerating fires. A management policy excluding disturbance would eventually lead to a decline in the importance of cedar (Motzkin et al. 1991)."
Regeneration is favored when fire occurs when the water table is near the surface, thus preventing consumption of the peat, and when a seed source is present, either from nearby trees or stored in the upper few inches of peat (Ackerman 1932, Frost 1995, Little 1950). In other situations, regeneration is successful after severe fires burn down close to the water table, thus creating moisture conditions favorable for seedling establishment (Little 1950). In this situation, however, seed would have to come from adjacent stands.
Restoration of Atlantic white cedar ecosystems is a high priority for the Albemarle-Pamilico Ecosystem Team as well as the Albemarle-Pamlico Coastal Program. In addition, the prospect of growing significant amounts of AWC again on private land now in permanent agriculture or other uses is almost nil. AWC requires at least 70 years, if used for siding and paneling, and larger trees suitable for more profitable boat lumber require much longer (Ward 1989). Thus, "the cedar industry should expect an increasing proportion of its diminishing supply to come from public lands where controlled logging is included within the management plan (Ward 1989)".
A fundamental problem in replenishing AWC is lack of planting stock; until that problem is resolved, little progress will be made. AWC is easy to vegetatively propagate from stem cuttings, but that method has drawbacks, including high labor intensity and costs. Questions about long-term performance of vegetatively propagated plants would require a long time to answer, perhaps 75 to 100 years. Consequently, we have chosen to focus on methods for production of high quality AWC bare-root and containerized AWC seedlings and transplants from seed. In addition, other work has dealt with seed technology, seedling physiology, practices for establishment of seedlings and transplants in the field, and water quality.
Reference: Hinesley, L. E. 2000. Pocosin Lakes National Wildlife Refuge: Forest Habitat Management Plan. Dept. of the Interior, U. S. Fish & Wildlife Serv. Draft document. 80 p.
II. STUDIES WITH ATLANTIC WHITE CEDAR
The following is a listing of some of the research that has been carried out to study seed technology, physiology, nursery practices, and regeneration of AWC and baldcypress. Participants include the N. C. Division of Forest Resources, the U. S. Fish & Wildlife Service, and faculty and graduate students at N. C. State University. The list is not all inclusive, but highlights major activities and findings.
1. Production of AWC transplants in outdoor nursery beds: effect of shade, incorporated peat, and initial seedling size.
Several studies have addressed cultural practices for seedlings in standard nursery beds at the N. C. Forest Service nursery in Goldsboro (two abstracts below).
Abstract 1: One-year-old seedlings of Atlantic white cedar [Chamaecyparis thyoides (L.) B. S. P. ] were grown for 1 year in a transplant bed to determine the effects of factorial combinations of seedling size, shade, and peat amendments on nursery growth and subsequent first-year field performance. Growth in the nursery was improved by shade and peat. Resulting transplants, 0.4 to 0.7 m tall, were established in the field, using three site preparation treatments: none, roll & chop, and mounding. Survival and first-year height were similar for the three site preparation treatments. Small, but significant, residual effects of peat amendments and shade were still evident after one growing season in the field. Damage from deer and rabbits reduced total height by about 30% the first year.
Reference: Hinesley, L. E. , L. K. Snelling, G. A. Pierce, and A. M. Wicker. 1999. Effect of peat amendments, shade and seedling size on growth of Atlantic white cedar transplants. Southern J. Appl. Forestry 23: 5-10.
Abstract 2: The North Carolina Division of Forest Resources started production of AWC bare-root seedlings in the early 1980s. Problems with seedling quantity and quality led to a series of studies to determine the characteristics of acceptable seedlings, and nursery practices for their consistent production. This paper describes results from three of those studies established between 1989 and 1996; seedling comparison, nursery bed seedling production, and seedling size evaluation (Summary below).
Reference: Summerville, K. O., W. E. Gardner and L. Eric Hinesley. 1999. Atlantic white cedar plant production. p. 68-75. In: Proceedings: Atlantic white cedar: ecology and management symposium, Aug. 6-7, 1997. USDA, Forest Service. Southern Res. Sta. Gen. Tech. Rpt. SRS-27.
Summary of results (Summerville et al. 1999):
Seedling comparison: three types of seedlings were compared: 1) small containerized (cell volume =3.0 cu in, ht = 6 in), 2) larger containerized (cell vol = 5.5 cu in, ht = 1 ft), and 3) bare-root (1-0 nursery stock, ht = 6 in). They were planted in replicated experiments on three sites representing a range of soil and vegetative competition conditions in eastern NC. Initial mortality was higher for bare-root plants. After 5 years, growth was best for the larger containerized stock. Performance of bare-root seedlings was intermediate between that of small and larger containerized stock.
Nursery bed seedling production: In 1994 and 1995, five soil treatments were factorially combined with two shade treatments in outdoor nursery beds at the NCFS nursery in Goldsboro. Plots either had 50% shade or no shade. Soil treatments included: 1) bed without mulch or amendment, 2) one bushel of lose sphagnum peat moss mixed into the top 6 inches of each 5-ft length of bed, 3) 0.5 in of peat moss spread on top of bed, 4) 0.5 in of a 1:1 mix of peat and vermiculite applied on top of bed, and 5) 0.5 inch of chopped pine straw mulch applied over the bed following seeding (standard practice).
Shade improved germination , and also resulted in the greatest number of plants per sq ft of nursery bed. Under shade, soil treatments 1-4 yielded more plants per sq ft, compared to straw mulch. Without shade, the straw mulch yielded the most plants per sq ft. Tmts 2 and 4 yielded a higher percentage of large plants, especially under shade. The distribution (% basis) of plants into various height classes was not affected by the presence or absence of shade. The best overall treatment was incorporated peat under shade.
Seedling size evaluation: Objective was to determine the minimum size bare-root seedling acceptable for transplanting to a reforested site. Six height classes of 1-0 seedlings were assigned: 0-5 cm, 5-10 cm, 10-15 cm, 15-20 cm, 20-25 cm, and > 25 cm. Seedlings were established in replicated experiments on four sites in eastern NC. As might be expected, the smallest seedlings experienced the most mortality, and produced the least growth. Height growth was greatest for the larger plants.
2. Effect of site preparation technique on early growth and survival on a Pungo soil at Pocosin Lakes National Wildlife Refuge (PLNWR).
Several studies have been carried out on Pungo soils at PLNWR to examine the effect of site preparation on regeneration of AWC and cypress. The area in question was ditched and drained for commercial farming between 1950 and 1990. In 1995, the dominant vegetation was broomsedge (Andropogan glomeratus (Walt.) B.S.P.), with smaller amounts of sedge (Cyperus spp.) and slender goldentop (Euthamia tenuifolia (Pursh) Nutt.), and scattered specimens of gallberry [Ilex glabra (L.) A. Gray)], wax myrtle (Myrica cerifera L.), evergreen bayberry (Myrica heterophylla Raf.), red bay ( Persea borbonia Spreng.), swamp bay (Persea palustris Sarg.), sweet bay (Magnolia virginiana L.), pond pine (Pinus serotina Michx.), swamp titi (Cyrillia racemiflora L.), fetterbush lyonia [Lyonia lucida (Lam.) K. Koch], and occasional patches of canebreak [Arundinaria gigantea (Walt.) Muhlenb.]. There is no seed source to naturally regenerate tree species. The peat is 7-9 ft thick, and is full of logs, stumps, and roots from old forest(s) that consisted mostly of baldcypress, Atlantic white cedar, and tupelo (Dolman and Buol, 1967).
a.Three site preparation techniques were compared: none, mounding with a tracked excavator, and mowing with a bushhog. Growth of transplants was influenced dramatically by deer and rabbits, as evidenced by a one-year net loss of height more than 30%. Damage was similar across site preparation treatments, indicating that concealing trees in vegetative cover was of no benefit.
Reference: Hinesley, L. E. , L. K. Snelling, G. A. Pierce, and A. M. Wicker. 1999. Effect of peat amendments, shade and seedling size on growth of Atlantic white cedar transplants. Southern J. Appl. Forestry 23: 5-10.
In another replicated study, two site preparation treatments were used: none vs. heavy disking. Site prep treatment had no significant effect on first-year survival, but it appeared that the disked plots experienced more browsing. After 2 years in the field, survival and growth of cypress was better in the disked plots, whereas results for AWC and pond pine (Pinus serotina Michx.) were similar between site prep treatments.
Reference: Hinesley, L. E. and A. M. Wicker. 1997. Atlantic white cedar wetland restoration project: Pocosin Lakes National Wildlife Refuge. Report for Non-point Source Pollution Demonstration Project, 1997. U. S. Fish & Wildlife Service. 29 p.
Slide 1 Slide 2 Slide 3 Slide 4 Slide 5 Slide 6 Slide 7 Slide 83. Protecting newly established Atlantic white cedar and baldcypress with electric fences, Treeshelter tubes, wire mesh cages, and tall fences.
Efforts to replant AWC and cypress on Pocosin Lakes National Wildlife Refuge have been hindered by severe damage from white-tailed deer and rabbits. Surveys (unpublished) on Pocosin Lakes National Wildlife Refuge have indicated deer populations as high as 100 deer per km2. Observations in northeastern United States (Jones et al. 1993) indicate that herds exceeding 50 deer per km2 can negatively impact species richness, abundance, and composition; and populations above 125 deer per km2 can totally eliminate all ground vegetation in some systems, including threatened and endangered species. In unprotected plantings on Pocosin Lakes National Wildlife Refuge, extensive damage soon after planting has made it impossible to determine the early growth potential of AWC and cypress. One study used 1-1 transplants about 0.5 m tall, and there was a 30% net loss in height the first year ( Hinesley et al. 1999). The first large planting at Pocosin Lakes National Wildlife Refuge enclosed 120 ha, and was surrounded with a Gallagher-style electric fence that proved to be relatively ineffective (Hinesley and Wicker 1997). More recently, damage has been minimal in smaller plots up to 1-ha in area. Given the need to find a workable method to establish AWC and cypress, we initiated an experiment to compare several methods of mechanical protection for newly planted trees (abstract below).
Abstract : Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] (1-1 transplants = one year as a seedling and 1 yr in a transplant bed ) and baldcypress [Taxodium distichum (L.) Rich] (1-0 seedlings = 1 yr in a seedbed) were hand planted on a drained Pungo soil in Washington County, North Carolina Trees were protected from deer and rabbits by 1) electric fences, 2) Tubex Treeshelters, 3) hardware cloth cages, and 4) tall fences made of hardware cloth. In the following 3 years, white cedar produced up to 1.8 m of new growth; cypress grew much slower. Protection devices, although effective, were judged to be too expensive to be feasible in large plantings on this site.
Reference: Hinesley, L. E., S. A. Smith, and A. M. Wicker. 2000. Protecting newly established Atlantic white cedar and baldcypress with electric fences, tree shelter tubes, wire cages, and total exclusion plots. In: Atlantic white cedar management and restoration ecology symposium. Christopher Newport Univ., Newport News, Va. 31 May to 02 Jun 2000. (In press ).
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4. Greenhouse production of Atlantic White Cedar seedlings.
Abstract 1: Laura Greenwood, a Masters student in the Dept. of Forestry, N. C. State University, carried out research to 1) determine the effect of soil media characteristics on germination of AWC, and 2) determine the response of AWC seedlings to varying levels of N and P . Various combinations of mineral soil, peat, perlite, and vermiculite were evaluated in their effect on seed germination. In one experiment, germination percentages were highest in peat moss and 1:1:1 peat:perlite:vermiculite. In a second experiment, peat:vermiculite (1:1) yielded the best germination percentage. Soil-peat combinations resulted in significantly higher germination percentages than soil alone. For containerized production, 1:1 peat:vermiculite is the best germination media of those surveyed. For nursery beds, amending the soil with peat moss should improve germination.
Seedlings from the first germination experiment were fertilized with nitrogen from (NH4)NO3 at 0, 75, 150, and 300 ppm. After 6 months, seedlings grown in peat moss with 300 ppm N applied weekly were the tallest and had the greatest dry weight and stem diameter. Response to N depended on growing medium composition. Weekly fertilization with 160-250 ppm N should yield 90% to 95% of the maximum potential growth. Peat moss was the best medium, and loamy sand amended with peat was better than the soil alone. Peat should be the major component of any artificial medium, and should probably be added to nursery soils low in organic matter.
Seedlings from two seed sources were grown on 1:1:1 peat:perlite:vermiculite at 0, 25, 50, 100, or 200 ppm phosphorus from H3PO4. Seedlings grown at 0 ppm had reddish foliage and were smaller than those grown at the other concentrations. Seedlings grown at the other four concentrations of P were similar. Height and diameter differed between seed lots, but dry weights were similar. Weekly liquid fertilizer applications containing 25 ppm P are adequate for AWC seedlings.
Abstract 2: Many native species that are needed for environmental restoration can be grown in containers with overhead or drip irrigation. Sub-irrigation, has received more attention over the last decade because it reduces the use of water, fertilizer, and pesticides (3), and also protects local water sources by eliminating nursery and greenhouse irrigation runoff. The floatation system (sub-irrigation) utilized in the production of tobacco transplants in greenhouses, in addition to its low cost, is similar to that utilized by some native plant nurseries to produce wetland and riparian species. The objective of this research was to compare germination rates of Atlantic white-cedar under mist and two methods of sub-irrigation.
In August 2003, a replicated study was initiated in a greenhouse at NC State University in Raleigh, NC. Treatments were (1) float tray (float), 2) Ropak tray with overhead mist (mist), and (3) Ropak (flooded). Individual mist nozzles were used in treatment (1), and plastic liners were used to hold water for treatments (2) and (3). Three seeds per cell were sown in two types of containers, a 72-cell tobacco float tray and a 48-cell Ropak tray. Seeds were sown on Carolina Choice Germination and Plug Mix (Carolina Soil Co., Kinston, NC). The float and flooded treatments were placed in beds with 2 inches of water. Mist treatments occurred hourly from 8:00AM to 8:00PM.
After 8 weeks, differences among treatments were small. The number of cells occupied by at least one seedling was significantly higher with the float treatment (81%) compared to the mist (62%). Results for flooded trays were intermediate between mist and float treatments. Based on these results, the floatation system appears suitable for production of Atlantic white cedar from seed.
References:
Bell, A. C., M. M. Peet, and L. E. Hinesley. 2004. Alternative production of Atlantic white cedar and other native plants for wetlands and stream restoration in North Carolina. Proc. SNA Res. Conf., 49th Annu. Rpt. p. 353-355.
Greenwood, L. G. 1994. Greenhouse production of Atlantic white-cedar seedlings. M. S. thesis. Dept. of Forestry, N. C. State Univ., Raleigh. 87 pp.
5. Influence of container type on growth of Atlantic White Cedar seedlings, and subsequent performance in the field.
The nursery phase of this study was completed in 2001, but the field phase is still in progress. One-year-old (1-0) seedlings of Atlantic white cedar were lifted in February and transplanted into four types of containers (cell volume = 32 to 160 cu in). The growing medium was composted pine bark amended with 6 lbs/yd of 18-6-12 of controlled-release fertilizer (Osmocote). Plant growth increased with container size, although diameter and dry weight were more affected than height. Root systems were crowded in the two smaller containers by July 10, and were definitely root bound by Sept 10. The 3 x 3 x 9 inch container was adequate for containerized transplants through early September, when rooting space appeared to be exhausted. The largest container (4 x 4 x 10 inch) accommodated root growth throughout the entire growing season without excessive crowding. In March 2002, plants were established in replicated plots on Pocosin Lakes National Wildlife Refuge to observe residual effects of container type on growth the first year in the field.
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6. Influence of container volume, substrate, fertilizer, and irrigation regime on growth of AWC.
Abstract 1: Germination and growth of Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] was evaluated in response to four container volumes (98 cm3 to 530 cm3), two substrates [North Carolina Forest Service (NCFS) container mix (3 peat : 2 vermiculite : 1.5 perlite, by volume) and 3 pine bark : 1 peat], two controlled-release fertilizers [Osmocote 15N-9P2O5-12K2O, 12-14 month southern formulation, with micros; and Polyon 18N-6P2O5-12K2O with micros, 9-month formulation], and three irrigation frequencies (2, 3, or 4 times daily). Although growth increased up to the maximum container volume (530 cm3 = 32 cubic inches) , the optimum for 1-year-old seedlings appeared to be 164 to 262 cm3 = 10 to 16 cubic inches). The higher peat content and water holding capacity of the NCFS substrate yielded better growth than 3 bark: 1 peat. Osmocote yielded larger and heavier plants than Polyon, probably owing to more available phosphorus. Irrigation three times daily was optimum. Suitable manipulation of container volume, substrate, fertilizer, and irrigation should yield high quality containerized Atlantic white cedar seedlings.
Reference:
Derby, S. A. and L. E. Hinesley. 2005. Growth of Atlantic white cedar seedlings as affected by container volume, substrate, fertilizer, and water regime. HortScience 40: 1755-1759. pdf .
Abstract 2: Containerized Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] seedlings growing in composted pine bark were fertilized with five rates (0.0, 2.4, 4.8, 7.2, and 9.6 kg/m3) (0, 4, 8, 12, and 16 lb/yd3) of controlled-release fertilizers (CRF) [Osmocote 15N-9P2O5-12K2O, 12-14 month southern formulation, with micros; and Polyon 18N-6P2O5-12K2O, 9-month formulation, with micros]. Height, stem diameter, dry mass, and foliar nutrient concentrations were evaluated after 16 weeks. Growth was affected by fertilizer source and application rate, with no interaction. In general, the response to increasing fertilization was quadratic. Osmocote yielded larger plants than Polyon, probably owing to its higher P content. Osmocote (4.8 to 7.2 kg/m3) (8 to 12 lb/yd3) or Polyon (7.2 kg/m3) (12 lb/yd3) is suggested for container-grown seedlings the first year.
Reference: Derby, S. A. and L. E. Hinesley. 2005. Fertilizing containerized Atlantic white cedar seedlings. J. Env. Hortic. 23: 97-100.
7. Production of Atlantic White Cedar from vegetative propagation of stem cuttings.
The N. C. Forest Service has traditionally produced a small quantity of bareroot seedlings annually, but current demand for planting stock of AWC exceeds the supply. Another potential source of plants is stem cuttings, which root easily (Boyle and Kuser 1994, Hinesley et al. 1994).
Rooting response of stem cuttings varies according to time of collection, type of cutting, mist schedule, and type and/or concentration of rooting hormone. Rooting of AWC has been studied on a limited basis in greenhouses (Boyle and Kuser 1994, Hinesley and Blazich 1994), but not outdoors. Experiments were carried out to evaluate the influence of several factors (mist schedule, container type, cutting type, rooting medium, and IBA treatment) on the rooting capacity of AWC stem cuttings outdoors under shade (abstract below).
Abstract: Hardwood and softwood stem cuttings of 5-yr-old Atlantic white cedar [Chamaecyparis thyoides (L.) B. S. P. ] were cut to 12-cm (short) or 24-cm (long) lengths, treated with 0 to 15 g of IBA (1H-indole-3-butyric acid) per liter in 50% isopropyl alcohol, and rooted in a raised greenhouse bench under intermittent mist. When hardwood cuttings were collected in February, short cuttings survived and rooted better than long cuttings. Survival and percent rooting for softwood cuttings collected in late August was virtually 100% regardless of cutting length. Long cuttings produced more roots and longer roots with hardwood and softwood material. IBA was unnecessary for rooting, but it markedly increased the number of roots.
Reference: Hinesley, L. E., F. A. Blazich, and L. K. Snelling. 1994. Vegetative propagation of Atlantic white cedar by stem cuttings. HortScience 29:217-219.
Abstract: Stem cuttings of Atlantic white cedar [Chamaecyparis thyoides (L.) B. S. P.] were collected in early June 1995, divided into two parts (distal tip, and proximal segment), and rooted for 12 weeks in shaded containers outdoors. Total rooting was near 80%. Mist intervals of 8 and 15 min yielded the best rooting percentages and the least die-back and injury. Two rooting media were tested, with similar results. Rooting was slightly higher in Spencer-Lemaire Rootrainers (Hillson size), compared to RoPak Multi-pots (#45). More than 90% of the tips rooted, even without treatment with IBA (1H-indole-3-butyric acid). Auxin improved rooting of stem segments, but the difference between IBA at 1.5 and 3.0 gùliter-1 was small. Yield of cuttings suitable for transplanting or potting was 80% for tips; 58% for segments. Dividing stem cuttings into two or more parts allows multipication of rooted propagules from a collection.
Reference: Hinesley, L. E. and L. K. Snelling. 1997. Rooting stem cuttings of Atlantic white cedar outdoors in containers. HortScience 32: 315-317.
NOTE: Although vegetative propagation form stem cuttings is an alternative method for production of planting stock, we believe there are too many unanswered questions about the long-term results. Consequently, current efforts are focusing on operational production of plants from seed . However, it is likely that vegetative propagation will play a significant role in future efforts to genetically improve AWC.
8. Seedling physiology.
Efficient production of a species in nurseries requires a knowledge of plant response to environmental factors such as temperature and light. Studies were conducted in the Southeastern Plant Environment Laboratories at N. C. State University to 1) examine the growth of AWC seedlings under different temperature and light regimes (Fig. 1), and 2) compare heat tolerance of AWC from different geographic areas.
Abstract 1. Seedlings of Atlantic white cedar were grown in controlled-environment chambers for 12 weeks small, local conservation groups; individuals interested in learning more about AWC short- or long-day conditions with 9-hr days at 18, 22, 26, or 30C (64, 72, 79, or 86F) in factorial combination with 15-hr nights at 14, 18, 22 or 26 C (57, 64, 72 or 79F). Dry matter production was influenced by photoperiod and day/night temperature. For all day temperature x photoperiod interactions, except root:shoot ratio, growth was highest under long days. Day x night temperature interactions occurred for all growth measurements except root dry weight. Root dry weight was highest at 30/22C (86/72F); top (shoot) dry weight at 26/22C (79/72F). Nights of 14C (57F) resulted in the lowest top dry weight. Total plant dry weight was highest at nights of 22C (72F) for all day temperatures. At days of 30C (86F), total plant dry weight was highest with nights of 22C (72F); however, data for 30/22C (86/72F) and 26/22 (79/72F) were similar. The highest root:shoot ratio occurred at nights of 14C (57F) with days of 26C (79F). Mean relative growth rate was highest at nights of 22C (72F) with days of 26C (79F) or 30C (86F). Maximum stem caliper occurred at days of 22C (72F) with nights of 18C (64F). Height and crown width were highest at 26/22C (79/72F). A day/night cycle of 30/22C (86/72F) with long days was optimal for seedling growth.
Reference: Jull, L. G., F. A. Blazich, and L. E. Hinesley. 1999. Seedling growth of Atlantic white-cedar as influenced by photoperiod and day/night temperature. J. Environ. Hort. 17:107-113.
Abstract 2.Seedlings of six provenances of Atlantic white cedar [(Chamaecyparis thyoides (L.) B.S.P.)] (Escambia Co., Ala., Santa Rosa Co., Fla., Wayne Co, North Carolina, Burlington Co., N.J., New London Co., Conn., and Barnstable Co., Mass.) were grown in controlled-environment chambers for 12 weeks under 16-hour photoperiods with 16-hour days/8-hour nights of 22/18oC, 26/22oC, 30/26oC or 38/34oC. Considerable variation in height, foliage color, and overall plant size was observed among plants from the various provenances. Seedlings from the two most northern provenances (Massachusetts and Connecticut) were most heat sensitive as indicated by decreasing growth rates at temperature regimes >22/18oC. In contrast, plants from New Jersey and the three southern provenances (North Carolina, florida, and Alabama) exhibited greater heat tolerance as indicated by steady or increasing growth rates and greater top and root dry weights as temperature regimes increased above 22/18oC. Growth rates of seedlings from the four aforementioned provenances decreased rapidly at temperature regimes >30/26oC, suggesting low species tolerance to high temperatures. There were no significant differences in seedling dry matter production among provenances when temperature regimes were ~;34/30oC. Net shoot photosynthesis and dark respiration of plants did not vary by provenance; however, net photosynthesis was temperature sensitive and decreased at temperature regimes >26/22oC. Foliar respiration rates increased as temperature increased from 22/18oC to 26/22oC, but then remained relatively constant or decreased at higher temperature regimes. Plants at temperatures ~;34/30oC exhibited severe stunting, chlorosis, and necrosis on branch tips. However, tissue concentrations of N, P, K, Ca, Mg, Fe, Zn, Cu, and Mn generally increased with temperature regimes >30/26oC, indicating that mineral nutrient concentration was not a limiting factor at high temperatures.
Reference: Jull, L. G., T. G. Ranney, and F. A. Blazich. 1999. Heat tolerance of selected provenances of Atlantic white cedar. J. Amer. Soc. Hort. Sci.124: 492-497.
Abstract 3.Atlantic white cedar (Chamaecyparis thyoides (L.) B.S.P.) seedlings were grown for 16 weeks at 18/14 °C, 22/18 °C, or 26/18 °C in controlled-environment chambers. Four water table treatments were used in 20-cm pots (pot-in-pot) containing a pinebark substrate: 1) control (fully drained), 2) one-third full, 3) two-thirds full, and 4) completely full. Pots were watered twice daily with deionized water. They were fertilized once weekly with a modified Hoagland's solution (3-4 hours); then, flushed and refilled with deionized water. Growth (height, stem diameter, and dry weight) increased with increasing temperature regime, but temperature effects were minimal for flooded plants (Fig. 2, Slide 3). For most variables, the relationship of flooding levels to growth was quadratic; linear for temperature. Maximum height and dry weight occurred when pots were one-third to two-thirds full of water. Flooded plants yielded less growth, and had lower height/diameter ratios, compared to other water regimes. Root systems of flooded plants tended to form a mat near the soil surface (Slide 4).
Reference: Derby, S. A. and L. E. Hinesley. 2003. Water table and temperature regime affect growth of potted Atlantic white cedar. Proc. Atlantic White Cedar Mgt. & Restoration Symp., 02-04 June 2003. Arlington Echo Outdoor Education Ctr., Millersville, MD. In press.
Abstract 4. Chamaecyparis are ornamental plants that are used extensively in temperate-zone landscapes worldwide. However, due to their low tolerance to environmental stresses Chamaecyparis often perform poorly in urban landscapes. The objective of this research was to evaluate rootstocks of selected Cupressaceae taxa to determine their adaptability to poor drainage and high temperatures found commonly in urban landscapes. To accomplish this objective, 10 taxa (Chamaecyparis, Platycladus, and Thuga spp., and x Cupressocyparis leylandii) were grown in 2.8 liter (#1) black plastic containers with an 8 pinebark : 1 sand medium for 19 weeks in two greenhouses with 9/15 hr day/night temperatures of either 22C/18C (72F/64F) or 30C/26C (86F/79F). Half the plants in each greenhouse were flooded for 4 weeks. Root relative growth rate (RGR) was a better indicator of plant performance under flooded conditions compared to shoot RGR. At 22/18C (72/64F), root RGR of Chamaecyparis thyoides and Thuja 'Green Giant' only declined 10% and 11% between nonflooded and flooded plants, respectively. Chamaecyparis obtusa and x Cupressocyparis leylandii had the largest percentage decline in root RGR from nonflooded to flooded plants with 71% and 213%, respectively. Chamaecyparis thyoides had the highest root RGR at 30/26C (86/79F) in both nonflooded and flooded conditions with a 19% decrease in root RGR between nonflooded and flooded. Chamaecyparis lawsoniana and T. 'Green Giant' were ranked 2 and 3 in flooded conditions at 30/26C (86/79F); however, percentage decline increased to 43% and 46%, respectively. At this temperature, the remaining seven taxa had greater than 50% decline in root RGR in flooded conditions compared to nonflooded plants. In nonflooded conditions, shoot and root RGR of all species decreased from 22/18C (72/64F) to 30/26C (86/79F) except for Chamaecyparis thyoides. The shoot and root RGR of Chamaecyparis thyoides grown in 22/18C (72/64F) and 30/26C (86/79F) were similar in nonflooded conditions. Chamaecyparis thyoides demonstrated excellent tolerance to flooding and temperature and could be a desirable understock for other Chamaecyparis when grown in poorly drained locations.
Reference: Holland, B. T., S. L. Warren, and T. G. Ranney. 2003. Evaluating recovery of cupressaceae taxa after flooding at contrasting temperatures. J. Environ. Hort. 21:51-55.
Slide 1 Fig. 1 Slide 2 Fig. 2 Slide 3 Slide 4
9. Seed technology of Atlantic White Cedar.
Atlantic white cedar is a pioneer species that naturally grows in dense stands. It regenerates naturally if a seed source is available, vegetative competition is controlled, and the surface soil is moist. Part of the difficulty of artificially regenerating AWC is associated with the characteristics of its seed. There are about 400,000 seeds per pound. Seed collection is very tedious, and requires 'combing' the tiny cones off branches, which causes the bulk material to be "trashy". Often, a high percentage of seed is empty or unsound. In addition, the tiny seeds present challenges with respect to mechanical sowing with vacuum seeders.
Efforts by the N. C. Forest Service to grow seedlings in outdoor beds have consumed large quantities of seed in relation to the yield of seedlings. Given the scarcity of mature AWC stands - the source of seeds -- it is important to realize maximum yield of seedlings. More information is needed concerning seed technology of AWC to more efficiently utilize seed. To this end, a study was carried out in standard nursery beds at the N. C. Forest Service nursery in Goldsboro to determine the effect of soil treatment and shading on germination and yield of seedlings (Summary below).
Summary: In 1994 and 1995, five soil treatments were factorially combined with two shade treatments in outdoor nursery beds at the NCFS nursery in Goldsboro. Plots either had 50% shade or no shade. Soil treatments included: 1) bed without mulch or amendment, 2) one bushel of lose sphagnum peat moss mixed into the top 6 inches of each 5-ft length of bed, 3) 0.5 in of peat moss spread on top of bed, 4) 0.5 in of a 1:1 mix of peat and vermiculite applied on top of bed, and 5) 0.5 inch of chopped pine straw mulch applied over the bed following seeding (standard practice).
Shade improved germination , and also resulted in the greatest number of plants per sq ft of nursery bed. Under shade, soil treatments 1-4 yielded more plants per sq ft, compared to straw mulch. Without shade, the straw mulch yielded the most plants per sq ft. Tmts 2 and 4 yielded a higher percentage of large plants, especially under shade. The distribution (% basis) of plants into various height classes was not affected by the presence or absence of shade. The best overall treatment was incorporated peat under shade.
Reference: Summerville, K. O., W. E. Gardner and L. Eric Hinesley. 1999. Atlantic white cedar plant production. p. 68-75. In: Proceedings: Atlantic white cedar: ecology and management symposium, Aug. 6-7, 1997. USDA, Forest Service. Southern Res. Sta. Gen. Tech. Rpt. SRS-27.
In 1994, a graduate student (Laura Jull) conducted research in the Southeastern Plant Environment Laboratories at N. C. State University to determine the effect of stratification, temperature, and light on the germination of AWC from two provenances (Fig. 2) (abstract below).
Abstract: Seeds from two provenances (Wayne Co., NC, and Escambia Co., AL) of Atlantic white-cedar [Chamaecyparis thyoides (L.) B. S. P. ] were stratified (moist-prechilled) for 0, 30, 60, or 90 days at 4C (39F). Following stratification, seeds were germinated at 25C (77F) or 8/16 hr thermoperiods of 25/15C (77/59F) or 30/22C (86/68F) with daily photoperiods at each temperature of total darkness, 0.5, 1, 2, 4, 8, 12, or 24 hr. Seed germination of the Alabama provenance was greater than the North Carolina provenance for all treatments. There were no significant differences in percentage germination between 25/15C (77/59F) and 30/22C (86/68F) for any durations of stratification for either provenance. Regardless of stratification, germination was lowest at 25C (77F) for both provenances. When nonstratified seeds from the North Carolina provenance were germinated at photoperiods >12 hr, total germination never exceeded 5%, indicating an obligate light requirement. On the other hand, an obligate light requirement was not observed for seeds from the Alabama provenance since 15% of the nonstratified seeds germinated in darkness. However, for both provenances, stratification and daily photoperiods > 0.5 hr greatly increased germination. The North Carolina provenance required 90 days stratification to maximize germination (66%), whereas the Alabama provenance needed only 30 days (80%). High germination percentages were due, in part, to rigorous seed cleaning.
Reference: Jull, L. G., F. A. Blazich, and L. E. Hinesley. 1999. Seed germination of two provenances of Atlantic white-cedar as influenced by stratification, temperature, and light. J. Environ. Hort. 17: 158-163.
10. Characteristics of restoration sites, (no slides)
In 1998, Jason Guidry, a student in the Dept. of Forestry at N. C. State University, completed his research project on Pocosin Lakes National Wildlife Refuge in Hyde County, N. C. Though not mentioned in his abstract, this research also included a study related to protection methods for newly established planting stock.
Abstract: Water table profiles, plant community structure, herbaceous plant biomass production rates, and plant litter decomposition rates were measured for responses to the hydrological restoration of a pocosin wetlands ecosystem in eastern North Carolina. Changes in water-table profiles due to restoration were not found on the restored wetland. The plant community structure and composition of the restored site were significantly different from a reference site but this was attributable to divergent disturbance histories and not hydrological restoration. Herbaceous biomass production on the restored site (~239 g/m²/yr) was significantly less than on the reference site (~508 g/m²/yr); however, the differences could not be linked to hydrological changes; total herbaceous biomass production was comparable to that found in natural pocosin systems. Decomposition of plant litter was significantly faster on the restored pocosin (~29% of litter lost per year) than on the reference site (about 19%), perhaps indicating that hydrology was altered by restoration but not detected in the hydrological study; decomposition rates were similar to those found in natural pocosins. The general conclusion of this study was that the efforts to restore a natural hydrological regime to the disturbed wetland were insufficient in meeting the goals of ecological restoration.
Reference: Guidry, Jason L. 1998. Ecological restoration of a North Carolina peatland. M. S. thesis, Dept. of Forestry, North Carolina State Univ., Raleigh. 111 p.
11. Atlantic white cedar seedlings and transplants for wetlands restoration.
Plants are needed for planting demonstrations, public schools , non-government environmental groups; small, local conservation groups; individuals interested in learning more about AWC, and test plantings. In cooperation with the N. C. Forest Service at Goldsboro, we are producing 5,000 to 7,500 AWC containerized seedlings and transplants each year for the abovementioned purposes. About 4,000 plants were derived from rooted cuttings in 2001, but seedlings will be used in the future. Plants are provided at no cost. These plants help to provide a greater public awareness of AWC, and allow landowners to make preliminary evaluations of AWC with a small number of plants prior to making a bigger commitment on larger acreage. Some plants have been given to a local environmental group to establish a 'Millennium Forest' in Columbia, NC (Tyrrell Co.).
In fall of 2002, five thousand containerized AWC were donated to the SouthCarolina Department of Natural Resources (DNR) Wildlife Diversity Section for restoration work on Aiken Gopher Tortoise Heritage Preserve in Aiken County,S.C. Trees were donated by Dr. Eric Hinesley (North Carolina State Univ.), Greg Pate (N. C. Forest Service), and the Mike Wicker (U. S. Fish & Wildlife Service). The project was implemented by Johnny Stowe, statewide heritage preserve manager for the South Carolina Department of Natural Resources Wildlife Diversity Section, and a wildlife biologist and forester for the state's Heritage Trust Program. It was the first Atlantic white cedar restoration project on publicly owned and open-to-the- public land in South Carolina, according to Stowe. The two-foot-tall white cedars, often called junipers, were planted on a drained pond site along Spring Branch on the Aiken County preserve, an area acquired to protect a unique longleaf pine sandhills ecosystem containing the northernmost extant gopher tortoise population. Trees were measured periodically for growth and survival during 2003. Survival was close to 100%, and some seedlings reached more than 5 feet; the tallest was 6.3 feet. A few additional trees were also established on Clemson University's Sandhills Research and Education Center near Pontiac and on the Little Pee Dee River Heritage Preserve.
In December 2004, an additional 3 acres were planted with 1,500 AWC seedlings at a restoration site near the original planting. At that time, some trees in the original planting wer already up to 9 ft. tall
Slide 1 Slide 2 Slide 3 Slide 4 Slide 5 Slide 6 Slide 7 Slide 8
12. Seedling production by the North Carolina Forest Service (NCFS).
For the past 20 years, the NCFS has produced a nominal quantity of AWC seedlings in outdoor nursery beds. Results have been unpredictable, and often unsatisfactory, partly owing to low utilization efficiency of seed. In 2002, th NCFS produced about 140,000 containerized seedlings. This approach will likely be more efficient and economical than growing seedlings in standard nursery beds.
13. Weed Control in Nurseries.
Abstract 1: Goal 2E (oxyfluorfen) is labeled for broadleaf and grass weed control in conifer seedbeds, transplant beds and field plantings. Sureguard 51DF (flumioxazin) has a similar mode-of-action, and has provided similar levels of weed control at lower use rates. No injury to dormant conifers has been reported from Sureguard, but actively growing conifers differ in susceptibility to Sureguard. Furthermore, Sureguard has not been evaluated for safety on young conifer seedlings. Atlantic white cedar (Chamaecyparis thyoides) is a native conifer of growing importance in southeastern U.S. flood plain reforestation efforts. Currently, no herbicides are labeled for use in Atlantic white cedar seedbeds. This study was conducted to evaluate and compare the safety of Goal and Sureguard applied over-the-top of Atlantic white cedar seedlings.
The treatments were Goal at 0.25 and 0.5 lb ai/A, with and without 0.25% v/v non-ionic surfactant, compared to Sureguard at 0.25 lb ai/A with 0.25% v/v non-ionic surfactant. The seedlings, with 0.5-1.0? of new growth, were growing in cell packs in a greenhouse. The treatments were applied 2/26/02 using a CO2 pressurized backpack sprayer with two 8003 flat fan nozzles and calibrated to deliver 30 gallons per acre. Visual estimates of the percent of foliage damaged were conducted one week after application and then periodically through the first week of May.
One week after treatment, needle burn was apparent in all the treatments, but the Sureguard treatment produced the most severe damage (41%). Increasing oxyfluorfen dose and the addition of surfactant increased injury. Damage on the contacted foliage from Sureguard and Goal at 0.5 lb ai/A remained throughout the study. However, injury in all treatments was limited to the foliage existing at the time of treatment and new growth that emerged after treatment showed no signs of injury.
These data are consistent with previous research in which Goal and Sureguard injured some actively growing conifers. And, the injury from Sureguard to actively growing conifers is greater than that observed with labeled rates of Goal. However, weed control equivalent to labeled rates of Goal may be obtained with lower rates of Sureguard. For example: in container experiments we have found that 0.34 lb ai/A Sureguard provides similar preemergence weed control as 2 lb ai/A Goal. Therefore, further research is underway to evaluate the safety of lower doses and alternative application timing of Sureguard on seedling Atlantic white cedar.
| Treatment | Rate (lb ai/A) | 3/5/02 | 3/14/02 | 3/28/02 | 5/5/02 |
|---|---|---|---|---|---|
| Goal | 0.25 | 10c | 13d | 14c | 14c |
| Goal | 0.5 | 23b | 26bc | 24c | 23bc |
| Goal + NIS | 0.25 | 21b | 24c | 24c | 17c |
| Goal + NIS | 0.5 | 26b | 34ab | 40b | 33ab |
| Sureguard | 0.25 | 41a | 41a | 50a | 36a |
Means within a column followed by the same letter are not statistically different, based on a LSD means separation at p = 0.05.
III. INTRODUCTION - BALDCYPRESS
Like AWC, baldcypress (Taxodium distichum (L.) Rich.) has been an important tree of commerce in the South, including North Carolina. The total resource is only a fraction of that in earlier years even though demand is still strong. Ashe (1894) noted that the supply of cypress suitable for lumber and shingles in eastern North Carolina was almost gone, but there were still some large tracts in Tyrrell and Washington Co. In the South, harvesting of cypress peaked at 1.3 billion board feet (bbf) in 1913 (Krinbill 1956). The slack-line technique used by early loggers in southern swamps was described by Bryant (1913). The reserve of cypress sawtimber decreased from 40 bbf in 1913 to 13 bbf in 1953, with 1.2 billion board feet (bbf) in North Carolina (Betts 1960). In 1990, there was an estimated 2.1 bbf of cypress sawtimber in the northern Coastal Plain (Thompson 1990) and southern Coastal Plain of North Carolina (Johnson 1990).
The value of cypress lumber is in the heartwood, which is resistant to decay. Cypress, which can live more than 1000 years, produces little merchantable heartwood before 200-300 years in age (Betts 1960, Krinbill 1956, Hall and Maxwell 1911). By usual methods of forest valuation, It could be argued that high quality cypress is prohibitively expensive to grow in rotations of 200-300 years (Krinbill 1956). In addition, other factors also affect yield, e.g, the hydro-period influences wood quality; if the site is too dry, or if water levels fluctuate too much, trees tend to develop heart rot, become hollow or pecky, and produce a higher percentage of sapwood (Krinbill 1956; Pinchot and Ashe 1897). Although undesirable for timber quality, defects would benefit wildlife by providing more dens and nest cavities.
Cypress usually occurs in even-aged groups in all-aged stands (Matoon 1915), and rarely constitutes more than 25% of the stand (Pinchot and Ashe 1897). The most common associates are water tupelo on alluvial sites, blackgum on non-alluvial swamps and peat swamps, AWC and bays on muck soils, and AWC on peat soils (Matoon 1915).
Cypress occurs on soils ranging widely in texture, reaction, base saturation and fertility (Coultas and Duever 1984), but is normally confined to swamps where there is abundant moisture throughout the year (Fowells 1965; Matoon 1915). Cypress grows well on drier sites or more fertile sites, but its absence there is likely due to its inability to regenerate and compete with other tree species (Betts 1960. Matoon 1915). It is not demanding nutritionally, but is so exacting in regard to moisture that the area adapted for best growth is extremely limited, amounting to perhaps 300,000 acres in eastern North Carolina (Pinchot and Ashe 1897). Cypress is the dominant tree on alluvial soils, where fertility is augmented by nutrient- and sediment-laden water from outside the system.
In addition to its importance for timber, baldcypress is also important to wildlife. Historically, remote cypress swamps were a favored habitat of ivory-billed woodpeckers (Ridgeway 1898) as well as Carolina parakeets (Brewster 1889, Maynard 1881). Both species are now extinct. The potentially large size of cypress also makes it an important source of dens large enough to accommodate black bears and other animals. Seeds and fruits of cypress also represent a source of soft mast.
IV. STUDIES COMPLETED OR IN PROGRESS WITH BALDCYPRESS.
Regeneration of baldcypress is usually accomplished with 1-year-old (1-0) bare-root seedlings. Seedlings produced by the North Carolina Forest Service are normally 0.60 to 0.75 m tall (24 to 30 in), sometimes 1 m (40 in). The root system, with its large taproot and fibrous laterals, is easy to bar plant. In addition, the shoot (stem) tends to be straight with few lateral branches.
Heavy browsing by deer and rabbits on forest regeneration sites often results in unacceptably high mortality and deformed trees as well as significant loss of height during the first few years (Hinesley et al. 2000). Although planting trees up to 1.2 m tall (4 ft) might circumvent this problem on some sites, growing 2-year-old bare-root seedlings would not be practical due to their large size and resulting transplant shock. Production in containers is an alternative, but there is little information on container culture of this species.
In earlier research, baldcypress nursery stock in fabric bags grew best at high levels of nitrogen (N) fertilization, compared to several other genera of forest trees (Fuller 1988). On restoration sites in Louisiana, early diameter growth doubled after applications of controlled-release fertilizer (CRF) (Myers et al. 1995). Cypress best utilizes N under saturated, aerated conditions, and ammonium is a better N source than nitrate (Dickson and Broyer 1972). Given the possible need for containerized plants, we carried out an experiment to examine the response of containerized seedlings to lime, CRF, and soluble fertilizer (SF), and determine an optimum rate of incorporated CRF (Fig. 3) (abstract below).
Abstract: Two fertilization experiments were conducted with first-year seedlings of baldcypress [Taxodium distichum (L.) L. C. Rich.] in containers (substrate = composted pine bark). First, seedlings were subjected to factorial combinations of dolomitic lime, soluble fertilizer (SF), and incorporated controlled-release fertilizer (CRF) (19.0N-2.6P-8.8K; 8- to 9-month release). Lime decreased growth. Incorporated CRF [4.8 kg/m3 (8 lbs/yd3)] yielded more growth than a single weekly application of SF (N = 0.5 g/liter). In the second experiment, most of the potential height growth and total plant dry weight were realized with 2.4 kg/m3 (4 lbs/yd3) and 4.8 kg/m3 (8 lbs/yd3), respectively, of incorporated CRF. At optimal growth, foliar N concentrations were about 3.0%.
Reference: Hinesley, L. E. , Scott A. Smith and A. M. Wicker. 2001. Fertilization of containerized baldcypress. J. Environ. Hort.19:109-113.
V. WATER QUALITY - POCOSIN LAKES NATIONAL WILDLIFE REFUGE
Drainage, agriculture, logging, and fire have drastically changed organic soils in eastern North Carolina (Ashe 1894, Frost 1987, Hanlon 1970, Lilly 1981, McMullan 1984, Phillips et al. 1998). Historically, the two most important industries in the area were forestry and agriculture (Lilly 1981) . Drainage began before 1800, and considerable acreage in the Albemarle peninsula was converted to agriculture before 1900 (Ashe 1894, Lilly 1981, McMullan 1984). A law was passed in 1909 allowing the formation and financing of drainage districts (Pratt 1909). That law, combined with more efficient logging methods, led to rapid conversion of swamps to agriculture.
The Albemarle-Pamilico peninsula is the site of the greatest pocosin acreage in the United States (Ingram and Otte 1981, Richardson et al. 1981). Ruffin (1839) described Washington County (and perhaps the entire peninsula) as "one immense swamp , except for narrow knolls of firm soil scattered throughout - islands of sand, or of clay, in a sea of black mire". Today, most of the mineral soil, which is suited for agricultural use, is still in private ownership, but vast acreage of peatland has been absorbed by Pocosin Lakes NWR and Alligator River NWR. Most land within these Refuges is pallustrine (system); scrub-shrub or forested wetland (sub-class), broad-leaved evergreen or needle-leaved evergreen (dominance type), seasonally flooded (moisture class) (Cowardin et al. 1995).
The volume of peat on the Albemarle peninsula is probably less than half the original amount owing to the effects of drainage, agriculture, and fire (Lilly 1995). There are descriptions of subsidence >= 3 ft as a consequence of drainage and agriculture (Ruffin 1861, Dolman and Buol 1967, Lilly 1981, Roberts and Cruikshank 1941, Whitehead and Oaks 1979). Drainage of organic soils can result in the loss of at least one-third of the peat thickness (Farnham and Finney 1965), and sometimes more (Dolman and Buol 1967, Lilly 1981). Some of the initial loss in volume is due to mechanical shrinkage (Dolman and Buol 1967, Skaggs et al. 1980). In addition, drainage makes pocosins drier, which increases the frequency and severity of fires. Last, drainage causes peat to oxidize rather than accumulating. If subjected to drainage, fire, and tillage over a long enough period of time, all blackland soils will become mineral soils (Lilly 1981).
Drainage patterns on Pocosin Lakes National Wildlife Refuge have been described (Heath 1975, Soil Conservation Service 1994). Drainage water from Washington Co. and western Hyde County moves south in canals toward Clark-Mill Creek and Pungo River. According to North Carolina standards (Anonymous, 1993) for fresh surface water, Pungo River has a `C' classification. The `Best Usage' of such waters is -- "Aquatic life propagation and maintenance of biological integrity (including fishing, and fish), wildlife, secondary recreation, agriculture and any other usage except for primary recreation or as a source of water supply for drinking, culinary or food processing purposes." The `Conditions Related to Best Usage' are -- "The waters will be suitable for aquatic life propagation and maintenance of biological integrity, wildlife, secondary recreation, and agriculture; sources of water pollution which preclude any of these uses on either a short-term or long-term basis will be considered to be violating a water quality standard." As in all waters draining into the Tar-Pamlico Basin, Clark Mill Creek is also classified as nutrient sensitive (Clark 1994).
Water quality is affected by land use (Chescheir et al. 1990, Evans et al. 1989, Skaggs et al. 1980, Treece 1994). Drainage water from undisturbed forested watersheds carries a lower nutrient load than drainage water from developed soils. Development of organic soils results in large increases in the phosphorus (P) content of drainage water if fertilizer P is added, because the the soil does not bind P, as in mineral soils. Losses of N also increase, but not nearly to the extent noted for P. Restoration of wetland conditions in peatlands formerly drained for agriculture would likely reduce nutrient export, and improve water quality.
Peat Methanol Associates analyzed water quality in the area south of Phelps Lake to determine the potential impact of a proposed peat-methanol plant (Environmental Science and Engineering 1982). Unfiltered water samples in the major canals exceeded North Carolina standards for mercury and iron, presumably a result of seepage from surrounding peat land. Mercury bound to particles suspended in surface water draining the area would be an additional source of mercury that could affect filter feeders (e.g., oysters) in the Pungo River. The Tar-Pamlico River Basinwide Water Quality Management Plan (Clark 1994) also indicated that Clark Mill Creek and the upper end of the Pungo River were non-sustaining for their water use classification. Thus, there was a clear need to bring drainage waters into compliance with state standards and to reduce nitrogen loading.
In 1995, the U. S. Dept. of the Interior Fish and Wildlife Service began installing flashboard risers to restore wetland hydrology to a 17,000-acre tract targeted for wetland restoration on Pocosin Lakes National Wildlife Refuge (Fig. 4). An important objective of this project was to restore forest tree species that once occupied these sites. Swamp forests provide a number of amenities, including: greater evapo-transpiration, as opposed to runoff; an effective nutrient sink to reduce movement of nutrients off the site; a seed source for continuing natural regeneration; reduction of the subsidence that often occurs when organic soils are exposed to oxidation by exposure and disturbance, leading to discharge of mercury and other metals; and improved wildlife habitat.
The dominant vegetation was described earlier in Section I.2 concerning site prep experiments with AWC. Restoration of forest vegetation began in 1994-95 on a 640-acre (1.0 X 1.0 mile) site about 3 miles south of Lake Phelps (Hinesley and Wicker 1996, 1997, 1998). The soil is a Pungo muck, with peat averaging 7-9 ft thick. Elevation is about 15ft (4.6m) above sea level. Tree residue (logs, stumps) imbedded in the peat matrix is mostly AWC. Initially, a large replicated experiment (140 acres in plots) was installed involving two site prep treatments (disking vs. none), three species (cypress, AWC, and pond pine), and two planting densities (8 x 8 ft and 10 x 10 ft). Since that time, about 1,500 acres have been planted with AWC and cypress, plus a small amount of pond pine and longleaf pine. Results have been somewhat disappointing. Browsing by deer and rabbits was so severe that it was impossible to determine the real growth potential on these sites (Note: preventive measures were studied in a subsequent experiment). All species survived reasonably well, but after a few years, it was apparent that the site was most suited to pond pine and AWC. In general, growth of cypress has been very slow, although a little better near canals. If protected from browsing, AWC can grow 2 ft per year in height. Pond pine also showed good growth potential although Nantucket pine tip moths [Rhyacionia frustrana (Comstock)] sometimes caused heavy damage.
In the original project, a grid of stainless steel piezometers was systematically installed across the 640-acre area (Fig. 5). In addition to depth of the water table, nitrogen and mercury concentrations in surface water were measured quarterly for 3 years in canals adjoining the study blocks (Fig. 5). Each water sample was collected with a disposable teflon bailer, stored in an acid-washed bottle, and placed on ice. Each collection was shipped overnight to a lab in Washington state. Samples were preserved with 5% (v/v) 0.2N BrCl and allowed to oxidize overnight prior to analysis. Aliquots of each sample were analyzed using BrCl oxidation, SnCl2 reduction, dual gold amalgamation, and cold vapor atomic fluorescence (CVAFS) detection (EPA method 1631). On each collection date, two of the six sample sites were always sampled in duplicate for the mercury analysis. Water samples for N analysis were collected simultaneously with the Hg samples, placed on ice, and returned to a lab at North Carolina State University. Analysis included total Kjeldahl N, nitrite, nitrate, ammonia, and occasionally pH.
Water table levels in the two blocks ranged from 6 to 20 in in 1996, 8 to 20 in in 1997; 5 to 24 in during 1998, and 16 to 20 in during 1999 (Fig. 6). The seasonal variation in water table depth In 1996 and 1997 followed a typical pattern for wetlands: closer to the surface during late winter and early spring (more precipitation, less evapo-transpiration), and deeper during the summer months (less rain, higher evapo-transpiration). In 1998 and 1999, the deepest measurement occurred in December. Block B6, on the soth side of B5, consistently had a higher water table, possibly because it was bounded on the south side by a road, which probably slowed the southward movement of drainage water in Boerma Canal.
The objective of restoring wetland hydrology was not realized during the 5-yr project, as indicated by the lack of change in the water table depth after installation of a flashboard riser 0.5 mile south of Block B5 in summer 1997 (Fig. 6). Later, a decision was made to built up roads to allow higher water levels in canals, and presumably decrease the depth of the water table in the peat. Two new flashboard risers were installed in Boerma Canal in summer and fall of 1999, which required extensive drainage (May through the fall). This was possibly reflected in water table depths, which got no closer than 16 in from the surface throughout 1999, compared to 5 to 10 in during spring of the previous 2 years. Although no measurements were made after December 1999, water levels have definitely increased since installation of the new risers. The current array of risers on Boerma Canal offers the potential to retain a much greater volume of water on the site, compared to the old system, which will result in higher water tables and more anaerobic conditions, both of which should reduce oxidation of peat and the release of nutrients into drainage water.
At the conclusion of the project in 2000, export of nitrogen in the surface water of canals was still above the goal of 1.0 mg/liter of total N. On most sampling dates, total Kjeldahl nitrogen (TKN) was 2 to 3 mg per liter (Table 1), with ~;0.03 and 0.2 mg per liter of nitrate (Table 2) and ammonia (Table 3), respectively, and no measurable nitrite. Most of the nitrogen appeared to be complex organic compounds, probably resulting from the degradation of peat. This indicated that the soil was still oxidizing, and runoff was contributing to eutrophication in the downstream estuary. A decision was made to further raise water levels, which were still below naturally occurring levels on the site prior to drainage.
The goal of exporting less than 13 ppt of mercury in the surface water of canals was realized (Table 4 ). In 1997, 1998, and 1999, average mercury concentrations in surface water were 7-9 ppt. Unusually high values were recorded in December 1995 and 1996, but we could offer no explanation. Heavy construction activity in Boerma canal during 1999 caused no observable change in mercury concentrations in drainage water. However, in the latter part of 2000, concentrations edged up to about 10 ppt, possibly indicating a delayed effect from the extensive drainage the previous summer.
Hinesley , L. E. and A. M. Wicker. 1996. Atlantic white cedar wetland restoration project, Pocosin Lakes National Wildlife Refuge: report for firstt year of 319 Demonstration Project. N. C. State Univ., Raleigh, and U. S. Fish & Wildlife Serv., Raleigh. 30 p.
Hinesley , L. E. and A. M. Wicker. 1997. Atlantic white cedar wetland restoration project, Pocosin Lakes National Wildlife Refuge: report for 2nd year of 319 Demonstration Project. N. C. State Univ., Raleigh, and U. S. Fish & Wildlife Serv., Raleigh. 38 p.
Hinesley , L. E. and A. M. Wicker. 1998. Atlantic white cedar wetland restoration project, Pocosin Lakes National Wildlife Refuge: report for 3rd year of 319 Demonstration Project. N. C. State Univ., Raleigh, and U. S. Fish & Wildlife Serv., Raleigh. 16 p.
Fig. 4 Fig. 5 Slide 1 Slide 2 Slide 3 Fig. 6 Table 1 Table 2 Table 3 Table 4
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