Seedlings from 13 open-pollinated families of Taxodium distichum (L.) L.C. Richard from the gulf coast, central and south Texas, and Mexico were grown in a nursery in College Station, Texas. Forty seedlings per family were measured on three dates during the production cycle; 99, 109, and 133 days after sowing in Spring and Summer 2004. A two-step cluster analysis based on height and trunk diameter created 3 clusters of families. Cluster 1 had a mean height of 32 cm and a mean trunk diameter of 3.3 mm. Cluster 2 had a mean height of 33 cm and a mean trunk diameter of 3.4 mm. Cluster 3 had a mean height of 43 cm and a mean trunk diameter of 4.1 mm. Although clusters 1 and 2 are statistically significantly different, practically there is little difference between the two. The families from Mexico and central Texas were all in cluster 1 or 2 and the families collected from the gulf coast were all placed in cluster 3, with the exception of a single family from Biloxi, Miss., which was placed in cluster 1. Analysis of covariance revealed that family membership and days after sowing were both highly significant, as well as an interaction between family and days, for height. Families from Mexico and central and south Texas were 10 to 15 cm shorter than the families from the gulf coast, with the exception of the single family from Biloxi, Miss. Only days and the interaction between family and days were significant for trunk diameter. A pattern similar to the cluster analysis means was seen among the families for trunk diameter in the analysis of covariance.
Geoffrey C. Denny, W. Todd Watson, Leonardo Lombardini, Wayne A. Mackay, Alma R. Solis-Perez, Donita L. Bryan, and Michael A. Arnold
Geoffrey C. Denny, Michael A. Arnold, and Wayne A. Mackay
of these problems necessitates the selection and use of more adapted tree species and genotypes in urban areas. Taxodium distichum is a widely adaptable tree species for landscape use, tolerating both wet and dry soils and air pollution ( Cox and
Lijing Zhou, David L. Creech, Ken W. Krauss, Yin Yunlong, and David L. Kulhavy
; Templet and Meyer-Arendt, 1988 ; Wicker et al., 1981 ). Of all native swamp forest tree species in the southern United States, Taxodium distichum has been recognized as being among the most tolerant to flooding ( Hook, 1984 ) and salinity ( Krauss et al
Andrew R. King, Michael A. Arnold, Douglas F. Welsh, and W. Todd Watson
Baldcypress, Taxodium distichum (L.) Rich., is a species of ecological significance in the southeastern United States ( Arnold, 2008 ; Pezeshki and DeLaune, 1994 ). It is highly valued for its ornamental characteristics and site adaptability
Virginia Thaxton, Ed Bush, Ann Gray, and Paul Wilson
Proper irrigation practices are important in the production of container-grown woody ornamentals. When choosing irrigation methods, nurserymen must attempt to maximize production and comply with public policies mandating decreased water usage and runoff. One of these methods schedules irrigation based on plant demand, using tensiometers to measure matric potential of the substrate. While tensiometers have been used successfully with agronomic crops in the field, their effectiveness in irrigation management of large container-grown woody ornamentals has not been extensively tested. The objective of this study was to determine the effect of four irrigation treatments (7 cb tensiometer setting, 14 cb tensiometer setting, 1 time a day application, 4 times a day application) on the production of the ornamental tree Bald Cypress over a 9-month period. Growth differed significantly among treatments. The highest growth index was observed in the 4 times a day and the 7 cb tensiometer treatments, followed by the 1 time a day and 14 cb treatments, respectively. Effluent and leachate (pH, EC, N, P, K) were also measured. Percent effluent volume was highly variable, with maximum volume occurring in June for the 7 cb setting (82%) and in October for the 1 time a day treatment (47%). Higher pH values (7.0 to 8.0) initially occurred in the timed irrigation treatments and higher EC values (2.0–6.0 mmhos) were found in tensiometer treatments; over time, differences among treatments decreased for both variables. Substrate concentrations of N, P and K varied significantly among treatments, while no significant differences were found in the leaf tissue analysis.
Andrew R. King, Michael A. Arnold, Douglas F. Welsh, and W. Todd Watson
Baldcypress, Taxodium distichum (L.) Rich., is a highly adaptable tree of significant ecological importance in the southeastern United States ( Arnold, 2008 ; Pezeshki and DeLaune, 1994 ). Baldcypress is typically propagated commercially from
Garry Vernon McDonald, Geoffrey C. Denny, Michael A. Arnold, Donita L. Bryan, and Larry Barnes
Baldcypress ( Taxodium distichum ) is a medium to large deciduous tree with demonstrated adaptability to many difficult landscape sites, including urban locations with compacted or depleted soils, and exposure to poor air and water quality
Geoffrey C. Denny and Michael A. Arnold
varieties of T. distichum . Table 1. Key to botanical varieties of Taxodium distichum. Nomenclature After the taxonomic questions are answered, the question of appropriate nomenclature arises. Baldcypress was originally described by Linnaeus (1753) as
Geoffrey C. Denny* and Michael A. Arnold
An experiment was initiated to evaluate the effects of previously recommended seed treatments for baldcypress [Taxodium distichum (L.) Rich.] or pondcypress [Taxodium distichum (L.) Rich. var. imbricarium (Nutt.) Croom] on Montezuma cypress [Taxodium distichum (L.) Rich. var. mexicanum Gordon], and to determine which, if any, provided optimum germination. Factorial combinations of seed treatments and stratification (2 °C for 0, 45, or 90 d) were applied to seeds of Montezuma cypress. Treatments included: 1) 90% ethanol 5 min soak, 2) ethyl ether 5 min soak, 3) 100 mg·L-1 citric acid 48 h soak, 4) mechanical scarification, 5) five hot water baths (42 °C) allowing the water to cool to room temperature between baths, and 6) a non-treated control. Three more seed treatments consisted of water soaks at room temperature (25 °C) for 0, 45, or 90 d. Seeds were germinated on moist filter paper in a growth chamber with a 12-h day/night photoperiod at a constant 25 °C. Data was collected daily for 14 d and then weekly for the following 4 wks. Radicle elongation of 1 cm was considered germination. Without stratification, 100 mg·L-1 citric acid and the hot water bath treatments were significantly different from other treatments by 7 d, though not from each other, with a mean cumulative germination of 15.6% and 12.2%, respectively. By 14 d, the 100 mg·L-1 citric acid treatment differed only from the ethyl ether wash attaining 28.9% and 14.4% germination, respectively. There were no other statistically significant differences observed among any other treatments without stratification. Germination percentages were low,<30%, without stratification. Effects of additional stratification will also be discussed.
Michael A. Arnold, Larry J. Shoemake, and Mitchell W. Goyne
Transplant studies were conducted on Taxodium distichum L., Platanus occidentalis L., Quercus shumardii Buckl., Fraxinus velutina Torr., and Chilopsis linearis (Cav.) Sweet seedlings grown in 2.2- to 9.1-L black plastic containers. Effects of half-sib family selection on post-transplant root regeneration potential (RRP) and field establishment were investigated with P. occidentalis. Taxodium distichum, Q. shumardii, and P. occidentalis were used to determine seasonal variation in relationships among RRP characteristics and measures of successful transplant establishment. Post-transplant effects of avoidance of circling root development vs. remediation practices were investigated with Q. shumardii. Effects of container media composition on field establishment and RRP of container-grown plants were studied using F. velutina and C. linearis. Impacts of rotation time on RRP and field establishment were investigated with T. distichum. Rates of RRP were the measure most consistently linked to improved post-transplant shoot growth of P. occidentalis. Utilization of locally adapted genotypes and avoidance of summer transplant were important in establishment of P. occidentalis and T. distichum. Increased small diameter root regeneration was linked to reduced water stress during transplanting of Q. shumardii. Physical characteristics of the container media impacted initial post-transplant growth of F. velutina and C. linearis.