Tree Friendly Urban Soil Management: Amend, Fertilize, Mulch, Till!

Summary: Tree friendly urban soil management relies upon inorganic, microbial, organic, pH-adjusting amendments, fertilizers, mulches, plants and tillage.

Volcano mulching is an improper technique in which mulch is piled high up a tree's trunk; when applied properly, mulching is an easy, effective technique for improving urban soil quality and tree health: Robert Benjamin/Bugwood.org, CC BY 3.0 United States, via Forestry Images

The article Managing Soils That Support Urban Trees (Part Two), in Arborist News for August 2015, applies for soil modification inorganic, microbial, organic and pH-adjusting amendments, fertilizers, mulches, specialty plants and tillage.

Amendments bring biological, chemical and physical improvements: altered moisture content and power of hydrogen (pH); decreased contaminants and density; increased aggregation and fertility; and managed salinity. Coarse-textured materials and compost both correct organic matter content and respectively contribute to drainage and porosity in coarse-textured clay and moisture and nutrients in fine-textured sand. Low moisture content drives transportation costs down on weed seed-free composted and wood chip organic amendments compatible with soil pH and low in conductivity and salinity.

Ash, calcined clay, diatomaceous earth, expanded shale, expanded slate, gravel, perlite, sintered fly, vermiculite versus chips, compost, fresh manure, microbial inoculants exemplify inorganic versus organic amendments.

Amendments and mulches fight against compaction, erosion and temperature changes even though inorganic mulches furnish greater stability during high winds and for aggregation, microbes and nutrients.

Inorganic amendments generate lightweight soil mixes, grapple heavyweight loads with compaction-free after- and side-effects and guarantee porosity while organic mulches guard soil air and moisture levels. Soil pHs have best matches with tree species preferences and hold complicated scenarios of heading into original ranges whenever applications of acidifying or alkalizing amendments halt. Ammonium urea and protein-based amino acid fertilizers somewhat effectively, elemental sulfur and iron sulfate preferentially and potentially toxic aluminum sulfate reluctantly impel pHs into acidic ranges.

Calcium or magnesium carbonate, dolomitic lime with magnesium, pelletized or pulverized lime and wood ash jump pHs into alkaline levels in tree friendly urban soil management.

Excessive concentrations of sodium in degraded, drainage-poor, puddling sodic soils keep master arborists, master gardeners, master naturalists and tree stewards busy with high-quality water-diluted gypsum amendments.

Salt-tolerant plants lend gypsum remediative treatments helping roots and shoots by decreasing surface soil evaporation and increasing aggregate formation, macropores, organic matter, shade and water infiltration. Microbial inoculants maintain similar plant-based contributions to soil modification with hormone-stimulating Azospirillum phytostimulators, with nitrogen-fixing mycorrhizal bacteria and with pathogen-fighting Bacillus, Pseudomonas and Trichoderma biological controls. Compost teas in the microbial inoculant subcategory of soil amendments need organisms in compost diffused into water to negate harmful microbes and nurture beneficial microbial communities.

Impervious plastic weed-suppressing sheets within drip lines and 4-plus-inch- (10.16-plus-centimeter-) high volcano mulches in contact with tree trunks never occur in tree friendly urban soil management.

Air tilling postulates pre-moistened soil for supersonic air tools and prevails over radial trenching, roto-tilling and vertical mulching tillage options for reducing compaction around existing trees.

The efficacy of composted, 1- to 2-foot- (30.48- to 60.96-centimeter-) deep organic amendments through otherwise oxidation-, surface runoff-, soil erosion-prone mechanical tilling quickens before tree plantings. Tillage by 12- to 18-inch- (30.48- to 45.72-inch-) deep, trunk- to drip line-excavated radial trenches receives backfilled, high-quality amendments, such as rich compost, and replacement soils. Six- to 12-inch- (15.24- to 30.48-foot-) deep augered or drilled holes serve as vertical mulches with high-quality amended fill, inorganic or organic fertilizers or replacement soil.

Tree friendly urban soil management tenderizes compacted, contaminated, depleted, disturbed soils into sustainable treescapes, according to co-authors Wes Kocher, Bryant C. Scharenbroch and E. Thomas Smiley.

Proper site selection matches tree species with desirable soil pH; a spindly, stunted flowering dogwood (foreground) suffers in a site with soil pH of 8.1; flowering dogwood (Cornus florida L.) prefers moist, well-drained soils that are acidic (pH at 5.5 to 6.0) and are high in organic matter: Randy Cyr/Greentree/Bugwood.org, CC BY 3.0 United States, via Forestry Images

Acknowledgment

My special thanks to:
talented artists and photographers/concerned organizations who make their fine images available on the internet;
University of Illinois at Urbana-Champaign for superior on-campus and on-line resources.

Image credits:

Volcano mulching is an improper technique in which mulch is piled high up a tree's trunk; when applied properly, mulching is an easy, effective technique for improving urban soil quality and tree health: Robert Benjamin/Bugwood.org, CC BY 3.0 United States, via Forestry Images @ https://www.forestryimages.org/browse/detail.cfm?imgnum=5403664

Proper site selection matches tree species with desirable soil pH; a spindly, stunted flowering dogwood (foreground) suffers in a site with soil pH of 8.1; flowering dogwood (Cornus florida L.) prefers moist, well-drained soils that are acidic (pH at 5.5 to 6.0) and are high in organic matter: Randy Cyr/Greentree/Bugwood.org, CC BY 3.0 United States, via Forestry Images @ https://www.forestryimages.org/browse/detail.cfm?imgnum=1238083

For further information:

Gilman, Ed. 2011. An Illustrated Guide to Pruning. Third Edition. Boston MA: Cengage.

Hayes, Ed. 2001. Evaluating Tree Defects. Revised, Special Edition. Rochester MN: Safe Trees.

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Available @ https://earth-and-space-news.blogspot.com/2015/06/tree-friendly-urban-soil-management.html

Marriner, Derdriu. 18 April 2015. “Tree Wound Responses: Healthy Wound Closures by Callus and Woundwood.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/04/tree-wound-responses-healthy-wound.html

Marriner, Derdriu. 15 February 2015. “Urban Forest Maintenance and Non-Maintenance Costs and Benefits.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2015/02/urban-forest-maintenance-and-non.html

Marriner, Derdriu. 13 December 2014. “Tree Dwelling Symbionts: Dodder, Lichen, Mistletoe, Moss and Woe-Vine.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/12/tree-dwelling-symbionts-dodder-lichen.html

Marriner, Derdriu. 18 October 2014. “Tree Cable Installation Systems Lessen Target Impact From Tree Failure.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/10/tree-cable-installation-systems-lessen.html

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Available @ https://earth-and-space-news.blogspot.com/2014/08/flood-tolerant-trees-in-worst-case.html

Marriner, Derdriu. 14 June 2014. “Integrated Vegetation Management of Plants in Utility Rights-of-Way.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/06/integrated-vegetation-management-of.html

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Available @ https://earth-and-space-news.blogspot.com/2014/04/tree-twig-identification-buds-bundle.html

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Available @ https://earth-and-space-news.blogspot.com/2014/02/tree-twig-anatomy-ecosystem-stress.html

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Available @ https://earth-and-space-news.blogspot.com/2013/12/community-and-tree-safety-awareness.html

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Available @ https://earth-and-space-news.blogspot.com/2013/10/chain-saw-gear-and-tree-work-related.html

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Available @ https://earth-and-space-news.blogspot.com/2013/10/storm-damaged-tree-clearances-matched.html

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Available @ https://earth-and-space-news.blogspot.com/2013/08/storm-induced-tree-damage-assessments.html

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Available @ https://earth-and-space-news.blogspot.com/2013/06/storm-induced-tree-failures-from-heavy.html

Marriner, Derdriu. 13 April 2013. “Urban Tree Root Management Concerns: Defects, Digs, Dirt, Disturbance.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/04/urban-tree-root-management-concerns.html

Marriner, Derdriu. 16 February 2013. “Tree Friendly Beneficial Soil Microbes: Inoculations and Occurrences.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/02/tree-friendly-beneficial-soil-microbes.html

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Available @ https://earth-and-space-news.blogspot.com/2012/12/healthy-urban-tree-root-crown-balances.html

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Available @ https://earth-and-space-news.blogspot.com/2012/10/tree-adaptive-growth-tree-risk.html

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Available @ https://earth-and-space-news.blogspot.com/2012/08/tree-risk-assessment-mitigation-reports.html

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Available @ https://earth-and-space-news.blogspot.com/2012/06/internally-stressed-response-growing.html

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Available @ https://earth-and-space-news.blogspot.com/2012/04/three-tree-risk-assessment-levels.html

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Available @ https://earth-and-space-news.blogspot.com/2012/02/qualitative-tree-risk-assessment-risk.html

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Available @ https://earth-and-space-news.blogspot.com/2012/02/qualitative-tree-risk-assessment.html

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Available @ https://earth-and-space-news.blogspot.com/2011/12/tree-risk-assessment-tree-failures-from.html

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Available @ https://earth-and-space-news.blogspot.com/2011/10/five-tree-felling-plan-steps-for.html

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Available @ https://earth-and-space-news.blogspot.com/2011/08/natives-and-non-natives-as-successfully.html

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Available @ https://earth-and-space-news.blogspot.com/2011/06/tree-ring-patterns-for-ecosystem-ages.html

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Available @ https://earth-and-space-news.blogspot.com/2011/04/benignly-ugly-tree-disorders-oak-galls.html

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Available @ https://earth-and-space-news.blogspot.com/2011/02/tree-load-can-turn-tree-health-into.html

Marriner, Derdriu. 11 December 2010. “Tree Electrical Safety Knowledge, Precautions, Risks and Standards.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2010/12/tree-electrical-safety-knowledge.html

Scharenbroch, Bryant C.; Smiley, E. Thomas; and Kocher, Wes. August 2015. "Managing Soils That Support Urban Trees (Part Two)." Arborist News 24(4): 12-17.
Available @ http://html5.epaperflip.com/Viewer.aspx?docid=b962e09a-5bc5-4148-948a-a4d100d8ff6b#page=12