scholarly journals Changes in Tree Root Architecture Resulting from Field Nursery Production Practices1

2020 ◽  
Vol 38 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Gary Watson ◽  
Angela Hewitt

Abstract Nursery production practices subject tree root systems to mechanical and environmental factors that are not imposed on plants regenerated naturally from seed. Architecture of undisturbed root systems of nine trees species commonly planted in urban landscapes was compared to root architecture of these tree species produced using common field nursery production practices. When young nursery production seedlings are root-pruned prior to replanting, the loss of the lower portion of the main root and lateral roots emerging from it, and initiation of adventitious roots from the cut end, alter the root system architecture. Nursery production plants have 7 to 48 percent fewer natural lateral roots that could develop into flare roots than undisturbed plants. New roots initiated from the cut end of the main root on nursery production plants can substitute for the loss of lateral roots, if accepted practices are followed. Root architecture of trees is established early. With minor exceptions attributed to the loss of small roots less than 1 mm diameter, there were no significant changes in the number of lateral roots over the 4 year period in both nursery production and undisturbed plants. This consistent number of roots also suggests that pruning the main root did not stimulate additional lateral roots above the pruning cut. Root architecture of liner stock produced in nurseries can be equivalent to undisturbed root systems. Index words: Structural roots, root pruning, bare root, root depth, taproot, root flare. Species used in this study: Norway maple (Acer platanoides L.); green ash (Fraxinus pennsylvanica Marsh.); littleleaf linden (Tilia cordata L.); red maple (Acer rubrum L.); European white birch (Betula pendula Roth.); Kentucky coffee tree (Gymnocladus dioicus L.); domestic apple (Malus spp.); red oak (Quercus rubra L.); Siberian elm (Ulmus pumila Jacq.).

2009 ◽  
Vol 27 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Angela Hewitt ◽  
Gary Watson

Abstract Typical nursery production practices, such as root pruning and transplanting, can alter tree root architecture and contribute to root systems that are too deep. In a study of field-grown liner production, root architecture was examined at each stage of the production process, from first year seedlings or rooted cuttings, through 4 to 5 year old branched liners. Depth and diameter of structural roots were recorded on ten replications each of Acer saccharum, Gleditsia triancanthos, Pyrus calleryana, and apple seedling rootstocks; Platanus ‘Columbia’ clonal rooted cuttings; and apple EMLA 111 clonal rootstock produced by mound propagation. By the time the liners reached marketable size, most natural lateral roots emerging from the primary root were lost. Simultaneously, adventitious roots were produced deeper on the root shank at the pruned end of the primary root. These changes in architecture result in the formation of an ‘adventitious root flare’ that is deeper in the soil than a natural root flare. The depth of this new root flare is dependent upon nursery production practices and may influence the ultimate depth of structural roots in the landscape.


2020 ◽  
Vol 38 (4) ◽  
pp. 143-148
Author(s):  
G. W. Watson ◽  
A.M. Hewitt

Abstract The number and size of lateral roots of a tree seedling can be evaluated visually, and could potentially be used to select plants with better root systems early in nursery production. To evaluate how root architecture develops in young trees, root architecture of 37 species of trees was compared at two stages of development: as harvested seedlings, and then one year after replanting. The total number of lateral roots and the number of roots >2mm (0.08 in) diameter that were present on the portion of the taproot remaining on seedlings after standard root pruning were recorded. Neither could consistently predict the number of lateral roots on the root system one year after replanting. Development of roots (sum of diameters) regenerated from the cut end of the seedling taproot was equal or greater than lateral root development in 84 percent of evaluated species. Even when regenerated root development was significantly less than lateral root development, the regenerated roots still comprised up to 44 percent of the root system. Regenerated roots from the cut end of the taproot can become a major component of the architecture of the structural root system in nursery stock. Index words: structural roots, nursery production, root regeneration. Species used in this study: European black alder (Alnus glutinosa Gaertn.), green ash (Fraxinus pennsylvanica Marshall), quaking aspen (Populus tremuloides Michx.), European white birch. (Betula pendula Roth), river birch (Betula nigra L.), black locust (Robinia pseudoacacia L.), northern catalpa (Catalpa speciosa (Warder) Warder ex Engelm.), Mazzard cherry [Prunus avium [L.) L.], chokecherry (Prunus virginiana L.), American elm (Ulmus americana L.), Siberian elm (Ulmus pumilia L.), goldenchain tree (Laburnum anagyroides Medik.), northern hackberry (Celtis occidentalis L.), Cockspur hawthorn (Crateagus crus-galli L.), single seed hawthorn (Crateagus monogyna Jacq.), honeylocust (Gleditsia tricanthos L.), Japanese pagodatree [Sophora japonica (L.) Schott], Katsura tree (Cercidiphyllum japonicum Siebold & Zucc.), Kentucky coffee tree [Gymnocladus dioicus (L.) K. Koch], littleleaf linden (Tilia cordata Mill.), boxelder (Acer negundo L.), hedge maple (Acer campestre L.), Norway maple (Acer platanoides L.), red maple (Acer rubrum L.), silver maple (Acer saccharinum L.), sugar maple (Acer saccharum Marshall), sycamore maple (Acer pseudoplatanus L.), English Oak (Quercus robur L.), northern red oak (Quercus rubra L.), Siberian peashrub (Caragana arborescens Lam.), American plum (Prunus Americana Marshall ), Myrobalan plum (Prunus cerasifera Ehrh.), redbud (Cercis Canadensis L.), Russian olive (Elaeagnus angustifoliaI L.), tuliptree (Liriodendron tulipifera L.), black walnut (Juglans nigra L.), Japanese zelkova (Zelkova serrata (Thunb.) Makino).


2016 ◽  
Vol 42 (1) ◽  
Author(s):  
Edward Gilman ◽  
Maria Paz ◽  
Chris Harchick

There is a general understanding that roots deflect when striking solid nursery container walls, and that on trees with good vitality this occurs within weeks of shifting into larger containers. Root architecture is poorly understood when observed in containers with walls constructed of porous plastic and of materials other than plastic. The objective of this study was to measure impacts of container type, root pruning when shifting to a larger container, and cardinal direction on root architecture in nursery containers up to the #45 size (approximately 170 L). Trunk diameter in #45 containers varied less than 5 mm among eight container types and was not impacted by root pruning. More root growth occurred in the northern than southern half of containers. Container type had a small impact on root architecture; in contrast, root pruning by shaving the periphery of the root ball at each shift had a large impact. Shaving when shifting dramatically reduced the percentage of trees graded as culls and suppressed stem-girdling root formation compared to not shaving. Shaving shifted deflected woody root mass from the interior of the root ball to the exterior, making it simple to remove peripheral roots when planting into the landscape.


1972 ◽  
Vol 2 (3) ◽  
pp. 223-227 ◽  
Author(s):  
S. Eis ◽  
J. R. Long

Roots of Sitka spruce (Picea sitchensis) and western hemlock (Tsugaheterophylla) seedlings were side pruned in nursery beds at semimonthly intervals to produce dense and compact root systems. Root pruning early in the growing season stimulated the growth of existing roots and also initiated new roots. The densest root systems were produced by pruning before the end of June. However, because of the short length of lateral roots on seedlings early in their second growing season, pruning equidistant between rows 18 cm apart was ineffective. The best compromise appeared to be to prune spruce at the beginning of July, and hemlock around the middle of July. Earlier pruning equidistant between rows can be effective on larger seedlings during their third growing season. If early pruning is carried out on 2 + 0 seedlings, a pruning distance of about 6 cm from the row is recommended.


Author(s):  
B.N. Bochkaryov ◽  
◽  
N.V. Medvedeva ◽  
E.N. Ryzhenko ◽  
◽  
...  

We carried out the research in 2018-2019 at the experimental station of V.S. Pustovoit All-Russian Research Institute of Oil Crops. The aim of the research is to study the effect of certain morphometric characteristics of the overground part of plants and the architectonics of the root system on the sunflower lodging. We found significant differences in the architectonics of root systems in 17 maternal lines of sunflower: we identified three morphotypes, differing in the number and thickness of lateral roots of the first and subsequent orders, located in the top soil. We identified the sunflower lines that have a root system with a well-developed main root and many lateral roots of various orders (type A), lines with a normally developed main root and a small number of lateral roots (type B), and lines with a poorly developed main root and few lateral roots in top soil (type C). We identified the presence of both low and high lodging in sunflower lines with different types of root systems. At the same time, there is a tendency towards higher lodging in lines with root system types B and C. The line SL12 3660 showed the maximum lodging resistance during two years of observations. It may be of interest for further work as a possible source of a lodging resistance trait.


Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 798
Author(s):  
Shanon Hankin ◽  
Gary Watson

For urban trees with strong taproots, a shift in root growth towards increased lateral root development could improve tree performance in compacted, poorly drained urban soils. In effort to achieve this desired shift, various propagation and production practices exist within the nursery industry. However, the effectiveness of practices used to disrupt taproot development, as well as their impact on root architecture, has been largely undocumented. To determine how seedling root systems respond to taproot growth disruption, we pruned oak seedling taproots either mechanically at 5 and/or 15 cm, or via air pruning at 15 cm. Taproot regeneration and lateral root development were evaluated after two years. Taproot pruning resulted in multiple regenerated taproots. The location and number of times the taproot(s) was pruned did not appear to alter the ultimate number. Mechanical taproot pruning did not affect lateral root development above the first pruning cut location at 5 or 15 cm, but generally increased the density of lateral roots below the pruning cut, likely due to the multiple taproots present. Most lateral roots were fine roots less than 1 mm in diameter (fine roots), being unlikely to become long-lived components of the root system architecture. The average number of lateral roots on air pruned (AP) seedlings was generally greater than on the same taproot segment of control (C) seedlings. To determine how these seedling changes impact the root regeneration of liner stock, we planted both taproot pruned and taproot air pruned seedlings in in-ground fabric bags filled with field soil (B) or directly into the field without bags (F). Root regeneration potential (RRP) at the bottom and lateral surfaces of the root ball were evaluated. There was less RRP on the lateral surface of the root ball in taproot air pruned, container-grown (CG) compared to taproot pruned, bare root (BR) bur oak liners, and there was no difference in red oak liners. The multiple taproots of mechanically pruned BR seedlings did not result in excessive taproot development as liners. In contrast, CG seedling taproots restricted by air pruning produced more regenerated taproots after transplanting. While seedling taproot growth disruption does disrupt the growth of a dominant single taproot and alters the architecture toward increasing the number of lateral roots, these practices do not result in laterally dominated root architecture at the liner stage of nursery production. Future research should determine how these production methods effect lateral root growth after a tree is established in the landscape and determine appropriate combinations of production methods for different species.


Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 753 ◽  
Author(s):  
Sujan Dawadi ◽  
Fulya Baysal-Gurel ◽  
Karla M. Addesso ◽  
Jason B. Oliver ◽  
Terri Simmons

Soilborne pathogens are a significant economic problem for nursery production in the Southeastern United States. The goal of this study was to determine the impact of cover crops on soilborne disease suppressiveness in such systems. Soils from red maple (Acer rubrum L.) plantation fields grown with and without cover crops were sampled, either while the cover crops were growing (pre-disked) or post-season, following cover crop incorporation into the soil (post-disked). Greenhouse bioassays were conducted using red maple seeds on inoculated (with Rhizoctonia solani (J.G. Kühn) or Phytophthora nicotianae (Breda de Haan)) and non-inoculated field soils. The damping-off, root rot disease severity, percent recovery of Rhizoctonia and Phytophthora, and pseudomonad population were examined during the two years of the experiment. Results showed that cover crop incorporation was beneficial for inducing disease supressiveness characteristics of soil. Cover crop incorporation into the soil significantly or numerically reduced disease severity and pathogen recovery in infested soil compared to the bare soil treatment. Cover crop incorporation was found to be partially associated with the reduction of seedling damping-off. The pseudomonad microbial population was greater when cover crop was present, and is thought to be antagonist to soilborne pathogens. Therefore, cover crops can be integrated in field nursery production systems to suppress soilborne pathogens.


2016 ◽  
Vol 42 (4) ◽  
Author(s):  
Edward Gilman ◽  
Maria Paz ◽  
Chris Harchick

Size of liner, root ball slicing when field planting, and field root pruning season were tested with intention of optimizing posttransplant performance of field-grown nursery stock. Trees planted into a field nursery from three container sizes and either root ball sliced or not when shifted to larger containers or planting to the field nursery, and root pruned in the field nursery in either the dormant season or growing season all had the same trunk diameter (144 mm) and tree height (6.4 m) three years after transplanting into the landscape. Container size influenced root attributes—including number and orientation—and anchorage rating of field-harvested trees. Trees planted from 11 L containers required more bending stress to winch trunks evaluated 12 and 25 months after transplanting than larger containers. Percentage of root systems graded as culls was reduced from 88 to 66 by root pruning when field planting, but root pruning resulted in a slight reduction in anchorage rating. Diameter of the ten largest roots at edge of field-harvested root ball decreased with size of container planted into field soil. Root pruning season had no impact on final tree height (4.3 m) at the conclusion of field production.


1987 ◽  
Vol 17 (8) ◽  
pp. 761-767 ◽  
Author(s):  
M. P. Coutts

Factors that influence the primary and secondary growth of roots are reviewed in relation to the development of the form of tree root systems. The development of occasional root apices of larger than average diameter is important because they form the main axes that undergo secondary thickening and become permanent members of the woody root system. The formation of these large apices is influenced by injury to, or reduced growth or dormancy of, the subtending main root axis and by proximity to the shoot. The base of the taproot and laterals is seen as a region strongly influenced by shoot activity, resulting in the formation of additional large root apices and enhanced secondary thickening to form the zone of rapid taper in trees, and in the formation of storage organs in some herbaceous species such as radish. The main root axes compete for assimilates and dominance is established between them at an early age. The unequal growth of competing lateral roots is influenced by the local environment of the roots of primary structure. The role of root apices on secondary growth is discussed with reference to work on herbaceous species. In trees the local environment has some direct effects on the root cambium, but such effects appear to be less important than the activity of the roots of primary structure. A hypothesis is developed incorporating the Japanese Pipe Theory for the allocation of assimilates for the secondary growth of tree roots.


2016 ◽  
Vol 42 (3) ◽  
Author(s):  
Edward Gilman ◽  
Maria Paz ◽  
Chris Harchick

Root pruning by shaving 12 L container root balls when shifting to 51 L containers did not impact Acer rubrum L. or Quercus virginiana Mill. root architecture within the top 12 cm of planted 51 L root balls five years later, despite marked differences at planting, and had no impact on tree height or trunk diameter increase. Root pruning in the nursery did not affect bending stress required to tilt Acer trunks up to five degrees (anchorage) either one, two, or three years after landscape planting. In contrast, anchorage was greater the second year after planting Quercus that were root pruned. Rotating trees 180 degrees at planting from their orientation in the nursery had no impact on Acer or Quercus anchorage, tree height, or trunk diameter. Rotating oak (not maple) trees 180 degrees at planting increased root cross-sectional area growing from the hot (south) side of the root ball when trees were rotated at planting.


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