Beginning in the early 1980s, there were reports of white oak ( Quercus alba L.) leaves losing interveinal tissues throughout the Midwest [ Green, 1985 ; Haugen et al., 2000 ; Leatherberry et al., 2004 ; Wisconsin Department of Agriculture
Jayesh B. Samtani, John B. Masiunas, and James E. Appleby
Gregory E. Frey, Tarik Durmus, Erin O. Sills, Fikret Isik, and Marcus M. Comer
-value timber trees greater opportunity to grow, offers a straightforward economic opportunity for some woodlot owners ( Bruhn and Hall, 2008 ; Gold et al., 2008 ). Oaks ( Quercus sp.), particularly white oak ( Q. alba ), are recognized as preferred species
Jayesh B. Samtani, John B. Masiunas, and James E. Appleby
.O. Phelps, J.E. Hinckley, T.M. 1979 Net photosynthesis and early growth trends of dominant white oak ( Quercus alba L.) Plant Physiol. 64 930 935 Elias, T.S. 1987 The complete trees of North America Crown
Robert M. Augé, Xiangrong Duan, Jennifer L. Croker, Craig D. Green, and Will T. Witte
We compared the potential for foliar dehydration tolerance and maximum capacity for osmotic adjustment in twelve temperate, deciduous tree species, under standardized soil and atmospheric conditions. Dehydration tolerance was operationally defined as lethal leaf water potential (Ψ): the Ψ of the last remaining leaves surviving a continuous, lethal soil drying episode. Nyssa sylvatica and Liriodendron tulipifera were most sensitive to dehydration, having lethal leaf Ψ of –2.04 and –2.38 MPa, respectively. Chionanthus virginiana, Quercus prinus, Acer saccharum, and Quercus acutissima withstood the most dehydration, with leaves not dying until leaf psi dropped to –5.63 MPa or below. Lethal leaf Ψ (in MPa) of other, intermediate species were: Quercus rubra (–3.34), Oxydendrum arboreum (–3.98), Halesia carolina (–4.11), Acer rubrum (–4.43), Quercus alba (–4.60), and Cornus florida (–4.88). Decreasing lethal leaf Ψ was significantly correlated with increasing capacity for osmotic adjustment. Chionanthus virginiana and Q. acutissima showed the most osmotic adjustment during the lethal soil drying episode, with osmotic potential at full turgor declining by 1.73 and 1.44 MPa, respectively. Other species having declines in osmotic potential at full turgor exceeding 0.50 MPa were Q. prinus (0.89), A. saccharum (0.71), Q. alba (0.68), H. carolina (0.67), Q. rubra (0.60), and C. florida (0.52). Lethal leaf Ψ was loosely correlated with lethal soil water contents and not correlated with lethal leaf relative water content.
Ramzy Khoury and Jimmy L. Tipton
Evergreen elm (Ulmus parvifolia), southern live oak (Quercus virginiana), and South American mesquite (Prosopis alba) were irrigated at 75%, 50%, and 33% of reference evapotranspiration for 2 years in Phoenix, Ariz. Each tree was irrigated with twenty-nine 3.8-L·h–1 drip emitters to a depth of 90 cm. Initial trunk diameters were about 4 cm. Water use was monitored by heat balance sap flow gauges and related to canopy volume, projected canopy area, and total leaf area. Oak used more water than elm, and elm more than mesquite under all irrigation regimes. Irrigation regimes had a greater effect on oak and elm water use than on mesquite, but all trees maintained an acceptable canopy regardless of treatment.
Ramzy Khoury and Jimmy Tipton
Evergreen elm (Ulmus parvifolia), southern live oak (Quercus virginiana), and South American mesquite (Prosopis alba) were irrigated at 75%, 50%, and 33% of reference evapotranspiration for 2 years in Phoenix, Arizona. Each tree was irrigated with twenty-nine 3.8-L·h–1 drip emitters to a depth of 90 cm. Initial trunk diameters were about 4 cm. Water use was monitored by heat balance sap flow gauges and related to canopy volume, projected canopy area, and total leaf area. Oak used more water than elm, and elm more than mesquite under all irrigation regimes. Irrigation regimes had a greater effect on oak and elm water use than on mesquite, but all trees maintained an acceptable canopy regardless of treatment.
Orville M. Lindstrom
The cold hardiness of seven deciduous hardwoods, red maple (Acer rubrum L.), white oak, (Quercus alba L.), green ash (Fraxinus pennsylvanica Marsh.), sweetgum (Liguidambar stryaciflua L.), sugar maple (Acer saccharum Marsh.), river birch (Betula nigra L.) and black cherry (Prunus serotina Ehrh.) were evaluated weekly during the fall, winter and spring for three consecutive years. All trees evaluated were established (20-40 years old) and locatd on the Georgia Station Griffin, GA. Each species developed a maximum cold hardiness of at least -30 C by mid-January or early February each season. Response to temperature fluctuations varied with species. Red maple, for example, lost less cold hardiness due to warm mid-winter temperatures than the other species tested, while white oak tended to respond more quickly to the temperature fluctuations. Data will be presented comparing the response of cold hardiness to mid-winter temperature fluctuations for each species for the three year period.
Jason Grabosky and Nina Bassuk
In the development of a street tree planting medium for use as a sidewalk base, we have been testing a series of limestone gravel and soil media with varied amounts of clay loam suspended within the matrix voids. Tilia cordata and Quercus alba seedling roots quickly penetrated and grew in these systems when compacted to densities in excess of 2000 kg·m–3, while they were severely impeded in clay loam soil compacted to 1300 kg·m–3. Limestone mixes of the same design had variable, but consistently acceptable, California Bearing Ratios (>40) when compacted to similar densities; demonstrating their strength as a pavement base. Tilia root growth, based on the volume collected from total root excavations after two growing seasons, increased a minimum of 300% in the limestone mixes over the compacted clay loam control when the treatments were compacted to ≈80% Standard Proctor Optimum Density. Root penetration of Quercus increased >400% in the limestone mixes over compacted loam in a 6-month trial compacted to 95% Standard Proctor Optimum Density.
Jimmy L. Tipton, Elizabeth Davison, and Juan Barba
Southern live oak (Quercus virginiana), and South American mesquite (Prosopis alba) were planted in a shallow soil (≈15 cm deep) underlain by indurated calcium carbonate in Tucson, Ariz. Oaks were planted in three hole sizes, with backfill amended or unamended with undigested wood material and with or without 9 cm of an organic surface mulch. The surface mulch was a blend of undigested wood material and yard waste compost. Initial oak trunk diameters were ≈2 cm. Mesquites were planted according to these treatments: 1) a hole 150 cm square with amended backfill, 2) a hole twice as wide and 30 cm deeper than the root ball with amended backfill, and 3) a hole five times as wide and no deeper than the root ball with unamended backfill. Initial mesquite trunk diameters were ≈4 cm. Sixteen (oaks) and 28 (mesquites) months after planting soil was removed from the planting holes by a sewage vacuum truck. We will report the effect of treatments on trunk and canopy growth, and root growth from the side and beneath the original root ball.
D.G. Levitt, J.R. Simpson, and J.L. Tipton
Although water conservation programs in the arid southwestern United States have prompted prudent landscaping practices such as planting low water use trees, there is little data on the actual water use of most species. The purpose of this study was to determine the actual water use of two common landscape tree species in Tucson, Ariz., and water use coefficients for two tree species based on the crop coefficient concept. Water use of oak (Quercus virginiana `Heritage') and mesquite (Prosopis alba `Colorado') trees in containers was measured from July to October 1991 using a precision balance. Water-use coefficients for each tree species were calculated as the ratio of measured water use per total leaf area or per projected canopy area to reference evapotranspiration obtained from a modified FAO Penman equation. After accounting for tree growth, water-use coefficients on a total leaf area basis were 0.5 and 1.0 for oak and mesquite, respectively, and on a projected canopy area basis were 1.4 and 1.6 for oaks and mesquites, respectively. These coefficients indicate that mesquites (normally considered xeric trees) use more water than oaks (normally considered mesic trees) under nonlimiting conditions.