Interaction of Two C 3 and C 4 Grasses with Seedlings of Acacia smallii and Celtis laevigata

1990 ◽  
Vol 35 (3) ◽  
pp. 316 ◽  
Author(s):  
O. W. Van Auken ◽  
J. K. Bush
Keyword(s):  
2021 ◽  
Author(s):  
Emilee M Poole ◽  
Michael D Ulyshen ◽  
Scott Horn ◽  
Patrick Anderson ◽  
Chip Bates ◽  
...  

Abstract The southeastern United States has been experiencing unexplained sugarberry (Celtis laevigata) mortality for over a decade, representing one of the most severe and widespread Celtis mortality episodes ever reported from North America. Here we describe external symptoms, progression of mortality, and the known geographic extent of the problem. More than half of all trees monitored at one site within the affected area died over five years of observation. Although many trees died within a year of first exhibiting symptoms (e.g., small yellow leaves, branch dieback, premature leaf fall), many others continued living for years after becoming symptomatic. A preliminary insecticide trial found no improvements in survivorship among trees treated with insecticides, emamectin benzoate and imidacloprid, relative to control trees. Our findings suggest the problem will likely continue and become more widespread in the coming years. Study Implications Sugarberry mortality in urban and forested environments is an ongoing problem that has the potential to spread throughout the southeastern United States and perhaps more widely, depending on the susceptibility of other native Celtis species. Many trees die within a year of first showing external symptoms, whereas others can live for many years after appearing symptomatic. Declining trees in rights-of-way and public spaces are presenting costly hazards to cities, and canopy gaps in natural areas are likely to facilitate the establishment and spread of invasive plants. Studies aimed at determining the cause of this problem are urgently needed.


1975 ◽  
Vol 14 (11) ◽  
pp. 2532-2533 ◽  
Author(s):  
Luis H. Santa-Cruz ◽  
Carlton E. Turner ◽  
Joseph E. Knapp ◽  
Paul L. Schiff ◽  
David J. Slatkin
Keyword(s):  

IAWA Journal ◽  
1990 ◽  
Vol 11 (1) ◽  
pp. 71-83 ◽  
Author(s):  
Roland R. Dute ◽  
Ann E. Rushing

Pit membranes between tracheary elements of Ulmus alata, Celtis laevigata, and Celtis occidentalis often contained tori. The degree of development of tori varied and was greatest in those membranes connecting elements of small diameter. Complete tori consisted of two wall thickenings adjoined by a central layer. In three dimensions the shape of the torus often approximated a grooved wheel. Initiation of thickening in the pit membrane occurred first on the side of the older cell and was well underway prior to the beginning of secondary wall synthesis. Torus formation resulted from the thickening of the primary walls of the pit membrane. Development of the torus was associated with membranous vesicles and cisternae but not with microtubule complexes as was reported in Osmanthus. The pit membranes in this study are capable of aspiration, and the tori may prevent rupture of the pit membrane during this process.


1985 ◽  
Vol 9 (1) ◽  
pp. 52-54 ◽  
Author(s):  
Charles A. Gresham

Abstract Woody species in a Santee River Swamp area were sampled before and three growing seasons after a summer clearcut. Basal area before harvest was 140 ft², 72% of which was sweetgum (Liquidambar styraciflua), sugarberry (Celtis laevigata), ash (Fraxinus spp.), laurel oak (Quercus laurifolia), and water oak (Q. nigra). Sugarberry dominated the regeneration 3 years after harvest in all but the larger size classes. Reproduction less than 3-feet tall occurred on 39% of the sampled area while 69% of the sampled area contained one or more stems 3 feet or taller. Regeneration species composition and spatial distribution was not considered acceptable and was attributed to the lack of postharvest treatment. Shearing or prescribed fire is recommended to dispose of residual stems and logging slash. Subsequent planting seed or seedlings of cherrybark oak (Q. falcata var. pagodifolia), water oak, or sweetgum should ensure an acceptable species composition.


1985 ◽  
Vol 146 (4) ◽  
pp. 564-569 ◽  
Author(s):  
O. W. van Auken ◽  
E. M. Gese ◽  
K. Connors

1971 ◽  
Vol 98 (2) ◽  
pp. 83 ◽  
Author(s):  
M. A. K. Lodhi ◽  
Elroy L. Rice

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