Professor Emeritus at the University of Illinois at Urbana-Champaign. Research interests in forest biology, symbiotic nitrogen fixation by trees, and soil microbial ecology. Currently retired and living in Southern California.
Street-tree inventories from 1932 and 1982 for two Urbana, Illinois neighborhoods were compared. ... more Street-tree inventories from 1932 and 1982 for two Urbana, Illinois neighborhoods were compared. Tree species with the greatest, total stem basal areas at breast height in 1932 were American and red elms (Ulmus americana and Ulmus rubra), eastern cottonwood (Populus deltoides), silver maple {Acer saccharinum), and sugar maple [Acer saccharum). Tree species in the two neighborhoods with the greatest total basal areas in 1982 were silver maple, sugar maple, sycamore {(Platanus occidentalis), and hackberry {Celtis occidentalis). Trees that survived the fifty years included 24 silver maples, 24 sugar maples, 9 sycamores, and 8 hackberries. There were fewer but larger trees in these two Urbana neighborhoods after fifty years. The total basal area of trees decreased only 12% while the total number of trees decreased by 41%. Dominance of American and red elms along streets in these neighborhoods changed after fifty years to a more uniform distribution of basal areas and a greater variety o...
... Titles, Soil nitrogen changes, early growth, and response to soil internal drainage of a plan... more ... Titles, Soil nitrogen changes, early growth, and response to soil internal drainage of a plantation of Alnus jorullensis in the Colombian highlands. Personal Authors, Carlson, PJ,Dawson, JO (Illinois Univ., Urbana (USA). Dept. of Forestry). Publication Date, (Apr-Jun 1985). ...
... Titles, Stomatal conductance of seedlings of three oak species subjected to nitrogen fertiliz... more ... Titles, Stomatal conductance of seedlings of three oak species subjected to nitrogen fertilization and drought treatments. Personal Authors, Hechler, WD (University of Illinois at Urbana-Champaign, Urbana, IL),Dawson, JO,DeLucia, EH. Publication Date, (Mar 1991). AGRIS Subj. ...
The recently developed Illinois Soil Nitrogen Test (ISNT) predicts corn's response to nitrog... more The recently developed Illinois Soil Nitrogen Test (ISNT) predicts corn's response to nitrogen fertilization. ISNT measures the combined concentration of ammonium and amino sugar-N in soils providing an alternative approach for N fertility assessment. This value corresponds ...
Growth and water use efficiency • were determined for 2-year-old white oak (Quercus alba), swamp ... more Growth and water use efficiency • were determined for 2-year-old white oak (Quercus alba), swamp white oak (Q. bicolor), shingle oak (Q. imbricaria) and pin oak (Q. i palustris) seedlings grown under three shade treatments (30, 55 and 73%) and two irrigation regimes (container capacity and mild drought). With species and water regimes combined, i the dry weight increment, root, stem, leaf, shoot dry weight and water use efficiency of the oaks decreased significantly as shade level increased from 30 to 73%. Shade had no effect on height increment, while shoot/root dry weight ratio increased with increasing shade. White oak and swamp white oak closely followed this overall pattern, but the only response shingle oak and pin oak exhibited to increasing shade levels was an increase in shoot/root ratio of 24 and 26%, respectively. With species and shade levels combined, experimentally imposed drought reduced the oak iii_ seedling dry weight increment, root, leaf, and shoot dry weights, ca...
Journal of Chemical Ecology[J. CHEM. ECOL.]., 1983
Nitrogen-fixing nurse crops and cocrops of plant species nodulated byFrankia andRhizobium have be... more Nitrogen-fixing nurse crops and cocrops of plant species nodulated byFrankia andRhizobium have been used to promote the growth of black walnut trees. Although walnut is known to inhibit the growth of certain associated plants due to its allelopathic derivative juglone (5-hydroxy-1,4-napthoquinone), juglone inhibition of symbiotic, nitrogen-fixing soil microorganisms had not been investigated. This research revealed that a concentration of 10(-3) M juglone absolutely inhibited the growth in vitro of aFrankia isolate from root nodules of red alder and ofRhizobium japonicum strain 71. Lesser concentrations of juglone inhibited the growth of these bacteria relative to the controls. The more-rapidly growingRhizobium strain exhibited slight growth at 10(-4) M juglone concentration, whereasFrankia growth was completely inhibited. Considering both the susceptibility of the host plant and nitrogen-fixing endophyte to the allelochemical juglone, caution should be exercised in selecting nitrog...
The increasing cost of synthetic fertilizers has stimulated interest in the nitrogen-fixing prope... more The increasing cost of synthetic fertilizers has stimulated interest in the nitrogen-fixing property of Rhizobium, particularly as genetic engineering techniques raise the possibility of a symbiotic relationship with cereals. By contrast, the similar root nodules formed by nitrogen-fixing actinomycetes of the genus Frankia have been relatively little studied. Yet, as this article shows, the actinorhizal plants have very considerable possibilities for the utilization of marginal lands, especially in developing countries.
Soil nitrogen concentration around AlnusglutinosaL. (Gaertn.) stems differed significantly both s... more Soil nitrogen concentration around AlnusglutinosaL. (Gaertn.) stems differed significantly both spatially and with the proportion of hybrid Populus in a 4-year-old mixed plantation near Rhinelander, Wisconsin. Single rows of Alnus bounded by adjacent rows of hybrid Populus had the greatest increase and concentration of nitrogen in the top 16 cm of soil. Alnus, with an adjacent row of Populus and an adjacent row of Alnus, had less total nitrogen concentration in the soil and there was little significant increase in total nitrogen concentration. Where Alnus trees had a row of Alnus on either side, the total nitrogen concentration was least, having decreased significantly from concentrations in soil prior to tree planting. Soil nitrogen accretion and concentration was always highest in the top 4 cm of soil. Results are consistent with speculation that competition-induced stress from shading by Populus or Populus allelochemicals results in early accretion of nitrogen in soil around Alnus intermixed with Populus.
FERGUSON, IS, and JW LEECH. 1978. Generalized least squares estimation of yield functions. Forest... more FERGUSON, IS, and JW LEECH. 1978. Generalized least squares estimation of yield functions. Forest Sci 24:27-42. GRIZZLE, JE, and DM ALLEN. 1969. Analysis of growth and dose response curves. Biometrics 25:357-381. SULLIVAN, AD, and JL CLUTTER. 1972. A ...
Street-tree inventories from 1932 and 1982 for two Urbana, Illinois neighborhoods were compared. ... more Street-tree inventories from 1932 and 1982 for two Urbana, Illinois neighborhoods were compared. Tree species with the greatest, total stem basal areas at breast height in 1932 were American and red elms (Ulmus americana and Ulmus rubra), eastern cottonwood (Populus deltoides), silver maple {Acer saccharinum), and sugar maple [Acer saccharum). Tree species in the two neighborhoods with the greatest total basal areas in 1982 were silver maple, sugar maple, sycamore {(Platanus occidentalis), and hackberry {Celtis occidentalis). Trees that survived the fifty years included 24 silver maples, 24 sugar maples, 9 sycamores, and 8 hackberries. There were fewer but larger trees in these two Urbana neighborhoods after fifty years. The total basal area of trees decreased only 12% while the total number of trees decreased by 41%. Dominance of American and red elms along streets in these neighborhoods changed after fifty years to a more uniform distribution of basal areas and a greater variety o...
... Titles, Soil nitrogen changes, early growth, and response to soil internal drainage of a plan... more ... Titles, Soil nitrogen changes, early growth, and response to soil internal drainage of a plantation of Alnus jorullensis in the Colombian highlands. Personal Authors, Carlson, PJ,Dawson, JO (Illinois Univ., Urbana (USA). Dept. of Forestry). Publication Date, (Apr-Jun 1985). ...
... Titles, Stomatal conductance of seedlings of three oak species subjected to nitrogen fertiliz... more ... Titles, Stomatal conductance of seedlings of three oak species subjected to nitrogen fertilization and drought treatments. Personal Authors, Hechler, WD (University of Illinois at Urbana-Champaign, Urbana, IL),Dawson, JO,DeLucia, EH. Publication Date, (Mar 1991). AGRIS Subj. ...
The recently developed Illinois Soil Nitrogen Test (ISNT) predicts corn's response to nitrog... more The recently developed Illinois Soil Nitrogen Test (ISNT) predicts corn's response to nitrogen fertilization. ISNT measures the combined concentration of ammonium and amino sugar-N in soils providing an alternative approach for N fertility assessment. This value corresponds ...
Growth and water use efficiency • were determined for 2-year-old white oak (Quercus alba), swamp ... more Growth and water use efficiency • were determined for 2-year-old white oak (Quercus alba), swamp white oak (Q. bicolor), shingle oak (Q. imbricaria) and pin oak (Q. i palustris) seedlings grown under three shade treatments (30, 55 and 73%) and two irrigation regimes (container capacity and mild drought). With species and water regimes combined, i the dry weight increment, root, stem, leaf, shoot dry weight and water use efficiency of the oaks decreased significantly as shade level increased from 30 to 73%. Shade had no effect on height increment, while shoot/root dry weight ratio increased with increasing shade. White oak and swamp white oak closely followed this overall pattern, but the only response shingle oak and pin oak exhibited to increasing shade levels was an increase in shoot/root ratio of 24 and 26%, respectively. With species and shade levels combined, experimentally imposed drought reduced the oak iii_ seedling dry weight increment, root, leaf, and shoot dry weights, ca...
Journal of Chemical Ecology[J. CHEM. ECOL.]., 1983
Nitrogen-fixing nurse crops and cocrops of plant species nodulated byFrankia andRhizobium have be... more Nitrogen-fixing nurse crops and cocrops of plant species nodulated byFrankia andRhizobium have been used to promote the growth of black walnut trees. Although walnut is known to inhibit the growth of certain associated plants due to its allelopathic derivative juglone (5-hydroxy-1,4-napthoquinone), juglone inhibition of symbiotic, nitrogen-fixing soil microorganisms had not been investigated. This research revealed that a concentration of 10(-3) M juglone absolutely inhibited the growth in vitro of aFrankia isolate from root nodules of red alder and ofRhizobium japonicum strain 71. Lesser concentrations of juglone inhibited the growth of these bacteria relative to the controls. The more-rapidly growingRhizobium strain exhibited slight growth at 10(-4) M juglone concentration, whereasFrankia growth was completely inhibited. Considering both the susceptibility of the host plant and nitrogen-fixing endophyte to the allelochemical juglone, caution should be exercised in selecting nitrog...
The increasing cost of synthetic fertilizers has stimulated interest in the nitrogen-fixing prope... more The increasing cost of synthetic fertilizers has stimulated interest in the nitrogen-fixing property of Rhizobium, particularly as genetic engineering techniques raise the possibility of a symbiotic relationship with cereals. By contrast, the similar root nodules formed by nitrogen-fixing actinomycetes of the genus Frankia have been relatively little studied. Yet, as this article shows, the actinorhizal plants have very considerable possibilities for the utilization of marginal lands, especially in developing countries.
Soil nitrogen concentration around AlnusglutinosaL. (Gaertn.) stems differed significantly both s... more Soil nitrogen concentration around AlnusglutinosaL. (Gaertn.) stems differed significantly both spatially and with the proportion of hybrid Populus in a 4-year-old mixed plantation near Rhinelander, Wisconsin. Single rows of Alnus bounded by adjacent rows of hybrid Populus had the greatest increase and concentration of nitrogen in the top 16 cm of soil. Alnus, with an adjacent row of Populus and an adjacent row of Alnus, had less total nitrogen concentration in the soil and there was little significant increase in total nitrogen concentration. Where Alnus trees had a row of Alnus on either side, the total nitrogen concentration was least, having decreased significantly from concentrations in soil prior to tree planting. Soil nitrogen accretion and concentration was always highest in the top 4 cm of soil. Results are consistent with speculation that competition-induced stress from shading by Populus or Populus allelochemicals results in early accretion of nitrogen in soil around Alnus intermixed with Populus.
FERGUSON, IS, and JW LEECH. 1978. Generalized least squares estimation of yield functions. Forest... more FERGUSON, IS, and JW LEECH. 1978. Generalized least squares estimation of yield functions. Forest Sci 24:27-42. GRIZZLE, JE, and DM ALLEN. 1969. Analysis of growth and dose response curves. Biometrics 25:357-381. SULLIVAN, AD, and JL CLUTTER. 1972. A ...
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