scholarly journals Establishment in Treeshelters I: Shelters Reduce Growth, Water Use, and Hardiness, but not Drought Avoidance

HortScience ◽  
1997 ◽  
Vol 32 (7) ◽  
pp. 1281-1283 ◽  
Author(s):  
Roger Kjelgren ◽  
Larry A. Rupp

We investigated water use and potential drought avoidance of Norway maple (Acer platanoides L.) and green ash (Fraxinus pennsylvanica Marsh) seedlings grown in protective plastic shelters. Gravimetric tree water use and reference evapotranspiration for fescue turf (ETo) were monitored for 1 to 3 days during the growing season. Water use of trees was 8% to 14% of ETo in shelters vs. 29% to 40% for trees not in shelters. Trunk diameter was affected more than whole-tree water relations by lack of irrigation, suggesting that the nonirrigated trees were subjected to only mild water stress. Shelters did not improve drought avoidance, as water potentials were generally more negative and trunk diameter increment was lower for nonirrigated trees in shelters. Maples in shelters were affected more adversely by lack of water than were ash. Higher temperatures in shelters also may have reduced trunk growth. Air temperatures were 13 °C warmer than ambient in nonirrigated shelters, but only 5 °C warmer in irrigated shelters. Tree shelters can reduce transpiration rates by over half, but benefits from reduced water loss may be offset by negative effects of higher air temperatures. Shelters reduced cold hardiness of both species, but maple was affected more than ash.

1997 ◽  
Vol 15 (4) ◽  
pp. 183-186
Author(s):  
Christine L. Murray ◽  
Glen P. Lumis ◽  
Calvin Chong

Abstract Two-year-old branched seedling whips of green ash, Fraxinus pennsylvanica Marsh. and European birch, Betula pendula Roth, were grown for two seasons (1991 and 1992) in 38-liter (# 10) rigid, plastic, in-ground containers in three different substrate treatments: 10%, 50% and 100% soil, containing 10:30:60, 50:30:20, or 100:0:0 of field soil:sphagnum peat:ground pine bark, respectively. Trees were also planted directly into the soil (field-grown) to serve as a baseline control treatment. Top dry mass, trunk diameter and root dry mass in 1991 and 1992 and two size categories of root dry mass (<3 and 3<6 mm) in 1991 were consistently greatest for container-grown trees in the 10% soil treatment and least in the 100% soil treatments. Corresponding results for the 50% soil treatment were intermediate between the other treatments or similar to the 10% soil treatment. In 1991, the top dry mass and trunk diameter of both species grown in containers with 10% soil and in 1992, the top dry mass of ash, in the same treatment, were greater than those of field-grown trees.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 794F-794
Author(s):  
Driss Iraqi ◽  
Isabelle Duchesne ◽  
Jacques-André Rioux

The most widespread deformation observed in container production is root circling. Consequently, root circling often reduces growth, root regeneration, and tree anchorage at transplanting time. The objectives of this study were to test the effectiveness of Cu(OH)2 lined containers on restriction of root tips, tree growth, and potential root regeneration (PRR). Two species were used in this study: Fraxinus pennsylvanica and Acer saccharinum. Species were grown for one season in containers lined with one of six combinations of polymer (P) (0, 30, and 60 g·m–2) and copper (Cu) (0%,0.4%, and 0.8%) -coated fabric. Two other treatments were included as controls: a plastic container and a fabric container. Seedlings of each species were harvest twice: at the first season and after being transplanted from 10- to 75-liter containers. Treatments were randomized in complete blocks with six repetitions. Results of root circling length and dry weight indicate good restriction of root tips for two combinations (30 g of P/m2–0.8% Cu; 60 g of P/m2–0.8% Cu) for all species. However, treatments did not cause any reduction in stem height, trunk diameter, or stem and root dry weight. At the end of the transplanting season, PRR was greater for two combinations (30 g of P/m2–0.8% Cu; 60 g of P/m2–0.8% Cu), especially for green ash. No significant differences were observed between a plastic fabric and the two treatments cited for the other growth parameters. No phytotoxic symptoms were observed throughout the experiment.


1979 ◽  
Vol 57 (9) ◽  
pp. 997-999 ◽  
Author(s):  
R. J. Reader

In laboratory freezing trials, cold hardiness of six types of bog ericad flowers differed significantly (i.e., Chamaedaphne calyculata > Andromeda glaucophylla > Kalmia polifolia > Vaccinium myrtilloides > Ledum groenlandicum > Vaccinium macrocarpon) at air temperatures between −4 and −10 °C but not at temperatures above −2 °C. At the Luther Marsh bog in southern Ontario, low temperatures (−3 to −7 °C) would select against May flowering by the least cold hardy ericads. Availability of pollinators, on the other hand, would encourage May flowering by the most cold hardy species. Presumably, competition for insect pollinators has promoted the diversification of bog ericad flowering peaks, while air temperature, in conjunction with flower cold hardiness, determined the order in which flowering peaks were reached.


2009 ◽  
Vol 27 (4) ◽  
pp. 229-233 ◽  
Author(s):  
Gary W. Watson

Abstract Exposed fine roots are subject to desiccation, which may affect their survival as well as new root growth following bare root transplanting. Fine roots of dormant 1-year-old green ash (Fraxinus pennsylvanica) and sugar maple (Acer saccharum) seedlings, subjected to desiccation treatments of 0, 1, 2, or 3 hours in December and March, lost up to 82 percent of their water. Root electrolyte leakage, a measure of cell damage, tripled after three hours of desiccation. The increase was moderately, but significantly, greater in March for both species. Desiccation treatments had no effect on fine root survival. Growth of new roots (RGP) was also unaffected by desiccation treatments. RGP of maple was greater in March than December, but not ash.


2020 ◽  
Author(s):  
Yaojun Zhang ◽  
Jiaqi Ding ◽  
Hong Wang ◽  
Lei Su ◽  
Cancan Zhao

Abstract Background: Environmental stress is a crucial factor restricting plant growth as well as crop productivity, thus influencing the agricultural sustainability. Biochar addition is proposed as an effective management to improve crop performance. However, there were few studies focused on the effect of biochar addition on crop growth and productivity under interactive effect of abiotic stress (e.g., drought and salinity). This study was conducted with a pot experiment to investigate the interaction effects of drought and salinity stress on soybean yield, leaf gaseous exchange and water use efficiency (WUE) under biochar addition. Results: Drought and salinity stress significantly depressed soybean phenology (e.g. flowering time) and all the leaf gas exchange parameters, but had inconsistent effects on soybean root growth and WUE at leaf and yield levels. Salinity stress significantly decreased photosynthetic rate, stomatal conductance, intercellular CO2 concentration and transpiration rate by 20.7%, 26.3%, 10.5% and 27.2%, respectively. Lower biomass production and grain yield were probably due to the restrained photosynthesis under drought and salinity stress. Biochar addition significantly enhanced soybean grain yield by 3.1-14.8%. Drought stress and biochar addition significantly increased WUE-yield by 27.5% and 15.6%, respectively, while salinity stress significantly decreased WUE-yield by 24.2%. Drought and salinity stress showed some negative interactions on soybean productivity and leaf gaseous exchange. But biochar addition alleviate the negative effects on soybean productivity and water use efficiency under drought and salinity stress. Conclusions: The results of the present study indicated that drought and salinity stress could significantly depress soybean growth and productivity. There exist interactive effects of drought and salinity stress on soybean productivity and water use efficiency, while we could employ biochar to alleviate the negative effects. We should consider the interactive effects of different abiotic restriction factors on crop growth thus for sustainable agriculture in the future.


1992 ◽  
Vol 10 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Roger K. Kjelgren ◽  
James R. Clark

Abstract Microclimates characteristic of urban park, plaza, and canyon spaces were related to physiology and growth of even-aged sweetgum (Liquidambar styraciflua L.) street trees. Microclimates, tree growth, and physiological responses were characterized diurnally and seasonally. Park and plaza sites received unobstructed sunlight while the canyon was limited to four hours of direct solar radiation in midsummer. Potential seasonal insolation was 44% of the potential maximum at the canyon and over 90% at the park. Afternoon air temperatures and vapor pressure deficits were somewhat greater at the plaza than the other two sites, and potential pan evaporation was nearly 50% greater over the season. Tree growth at the plaza and canyon acclimated physiologically and developmentally to the prevailing environmental conditions. Thinner leaves and less trunk growth when compared with the park were indications of shade acclimation in the canyon trees. This did not, however, appear to affect crown size or shoot growth of canyon trees. In contrast, plaza trees were sparse and stunted, exhibiting diminished crown size and diameter increment when compared with tree at the other sites. Less favorable water relations suggested that chronically higher evaporative demand and limited soil resources restricted growth of the plaza trees. Park, plaza, and canyon designations of urban spaces can provide a useful framework for predicting microclimatic factors that can affect tree growth for an urban site. Long-term growth and development, however, with in any of these urban spaces will depend on interactions with existing soil conditions.


2017 ◽  
Vol 47 (3) ◽  
pp. 231-246 ◽  
Author(s):  
Jaroslav Rožnovský ◽  
Tomáš Litschmann ◽  
Hana Středová ◽  
Tomáš Středa ◽  
Petr Salaš ◽  
...  

Abstract Urban environment differs from the surrounding landscape in terms of the values of meteorological parameters. This is often referred to as the urban heat island (UHI), which in simple terms means higher air temperatures in cities. The cause of these changes lies in the different active surfaces in cities, which subsequently results in a different radiation balance. The higher temperatures, however, also affect the living conditions in the city and during very high temperature periods can have negative effects on the health of the city inhabitants. The results presented in this paper are based on measurements taken over several years at locations near Hradec Králové, which is surrounded by different surface areas. Environment analysis was performed using the Humidex index. The obtained results show that replacing green areas with built-up areas affects temperatures in the city, when air temperatures are very high they significantly increase the discomfort of the inhabitants. Differences in the frequency of discomfort levels are observed especially during periods of high temperatures, at lower temperatures these differences are not significant. Higher frequencies of discomfort are observed at locations with artificial surfaces (asphalt, cobblestones, concrete) and in closed spaces. In contrast, locations with lots of green areas almost always have the value of this index lower or more balanced. The results should therefore be a valid argument for maintaining and extending green areas in cities.


1977 ◽  
Vol 1 (3) ◽  
pp. 23-25 ◽  
Author(s):  
James B. Baker

Abstract Cuttings of eastern cottonwood (Populus deltoides) and seedlings of sweetgum (Liquidambar styraciflua), water tupelo (Nyssa aquatica), American sycamore (Platanus occidentalis), and green ash (Fraxinus pennsylvanica) were planted on a slackwater clay (Vertic Haplaquept) in western Mississippi in two consecutive years and inundated soon after foliation. During each of the two years, survival following flooding was consistently high for water tupelo, green ash, and sycamore, low for cottonwood, and intermediate for sweetgum. With the exception of green ash, however, all species lost their leaves and died back to the root collar during flooding. Thus trees, other than ash, that were living at the end of the growing season had originated from root collar sprouts.


1979 ◽  
Vol 3 (4) ◽  
pp. 173-174
Author(s):  
John T. Talbert ◽  
Robert D. Heeren

Abstract A disproportionately large number of first-generation selections from natural stands of green ash (Fraxinus pennsylvanica Marsh.) have been male. A study was undertaken to determine if male and female green ash differed in several important economic characteristics. Only straightness differences could be shown to be statistically significant, and, even for this trait, several opinions were needed to detect male superiority. Sufficient variation should exist in natural stands to allow inclusion of superior individuals of both sexes in a tree-improvement program.


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