Palm Tree Identification and Pruning of Native and Naturalizable Palms

Summary: Co-authors A.D. Ali and Leonard Burkhart, Jr. of The Davey Institute discuss palm tree identification and pruning of native and naturalizable palms.

California fan palm (Washingtonia filifera) is the only palm native to the western U.S. and is prone to pink and bud rots; California fan palms in Palm Canyon, south of Palm Springs, Riverside County, southern California; March 2005: Stan Shebs, CC BY SA 3.0, via Wikimedia Commons

The Merriam-Webster Dictionary definition of trees as woody perennials whose single main stems assemble few or no lower branches assists palm tree identification, according to an article in Arborist News August 2017.

The 2,700-some species, unlike hardwoods and softwoods, bear conductive phloem and xylem tissue-filled vascular bundles, living outer pseudo-bark, no cambium or heartwood and one growing point. Crowns atop trunks rooted adventitiously cluster immature green, ripe black-brown, 0.5- to 1-inch (1.27- to 2.54-centimeter) fruits and small, stalked, white or yellow flowers. Compound leaves described as palmate (fan-like) or pinnate (feather-like) fronds display leaflets that defer to induplicate (v-shaped) or reduplicate (upside-down v-shaped) attachments from rachis (central ribs).

Frond shapes, leaflet attachments to smooth or spiny, trunk-attached petioles and trunk marks from circular- or diamond-shaped leaf scars emerge as aids in palm tree identification.

Proper pruning of dead or diseased foliage follows downward paths from above and outside trunk-encircling frond skirts and forms horizontal, 9:00 to 3:00 clock face-like attachments.

Pruning guards broken, freeze-, storm- or wind-damaged green compound leaves and even healthy fronds that generate no interference with or risk to people, structures and utilities. Pineapple pruning hones boots (persistent leaf bases) into bulbous shapes that harbor ivy, mushrooms, scorpions and snakes and that hydraulic pruners or pruning spades hack off. Proper treatment of heavy palm tree fruits involves applying the growth regulator ethephon to determinate blooming, regular flowering stalks and pruning indeterminate blooming, irregularly flowering stalks.

A.D. Ali and Leonard Burkhart, Jr. of The Davey Institute juggle 15 species in Palms: Woody Giants of the Monocots, Part I: Identification and Pruning.

Bismarck and king palms keep owners respectively stressed over pink rot, self-pruned foliage and spider mites and over 20-foot (6.096-meter) canopies too wide for small yards.

Cold and part-shade tolerances link blue hesper palms, with forked petiole thorns, and Chinese windmill palms, with brown fibers encircling slender trunks and graying with age. Fruits from Guadalupe palms, survivors of overgrazing by introduced goats on Mexico's namesake island, and from pindo palms make respectively date-like jams and pineapple-apricot-like jellies. Coconut oil, fruit husk fiber for manufacturing, edible fruit and sap boilable and fermentable into wine number among the respective coconut and Chilean wine palm products.

Proper palm tree identification operates against serious landscaping problems by optimizing accurate matches of correct palms in sustainable coastal outdoor and inland indoor North American environments.

Canary Island date palms prove particularly prone to lethal yellowing, palm leaf skeletonizer, palmetto weevil and, with Cuban royal palms, to basal stem and bud rots. Sabal palm buds (hearts) and true date palm fruits respectively qualify as consumable in salads and stews and as edible only from manually pollinated female trees. Older and younger fronds reveal frizzle-top symptoms in potassium-needy Cuban royal palms and, in alkaline soils, manganese-poor queen palms whose fruit litter rivals true date palms. California and spiny Mexican fan palms respectively suffer from pink and bud rots even though the former shows little of the latter's diamond scale fungus resistance.

Proper palm tree identification and maintenance treats California fan and Florida sabal palm trees as North American natives and the article's 13 other species as naturalizable.

North American native sabal palms (Sabal palmetto) may display bootjacks, a basketweave effect of persistent leaf bases (left), or smooth trunks after natural falloffs of leaf bases (right); sabal palms along Cruickshank Trail, Merritt Island National Wildlife Refuge, Titusville, Brevard County, central east Florida; Oct. 1, 2016: Katja Schulz (treegrow), CC BY 2.0, via Flickr

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:

California fan palms (Washingtonia filifera) in Palm Canyon, south of Palm Springs, Riverside County, southern California; March 2005: Stan Shebs, CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Palm_Canyon_water_3.jpg

sabal palms along Cruickshank Trail, Merritt Island National Wildlife Refuge, Titusville, Brevard County, central east Florida; Oct. 1, 2016: Katja Schulz (treegrow), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/treegrow/30169119246/

For further information:

Ali, A. D.; and Burkhart, Leonard Jr. August 2017. "Palms: Woody Giants of the Monocots, Part I: Identification and Pruning." Arborist News 26(4): 12-20.

Craft, Paul; Robert Lee Riffle; Scott Zona. 2003. The Encyclopedia of Cultivated Palms. Second edition. Portland OR: Timber Press.

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.

Marriner, Derdriu. 22 July 2017. “Commonly Planted, Potentially Phytoremediating Street Tree Species.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/07/commonly-planted-potentially.html

Marriner, Derdriu. 17 June 2017. “Root Loss From Root Pruning and Root Shaving of Stem-Girdling Roots.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/06/root-loss-from-root-pruning-and-root.html

Marriner, Derdriu. 27 May 2017. “Age and Canopy Area Cost Less and Tell More in Urban Tree Inventories.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/05/age-and-canopy-area-cost-less-and-tell.html

Marriner, Derdriu. 22 April 2017. “Urban Root Management: Big Infrastructure, Small Space, Stressed Roots.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/04/urban-root-management-big.html

Marriner, Derdriu. 12 March 2017. “Flexural Elasticity Modulus: Trees and Watersprouts Bend or Break.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2017/03/flexural-elasticity-modulus-trees-and.html

Marriner, Derdriu. 18 February 2017. “Plant Health Care Diagnostics When Plants and Places Wrong One Another.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/02/plant-health-care-diagnostics-when.html

Marriner, Derdriu. 14 January 2017. “Tree Fertilization for Fine Root Growth and Whole Root System Effects.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/01/tree-fertilization-for-fine-root-growth.html

Marriner, Derdriu. 17 December 2016. “Abiotic and Biotic Stress in Low Maintenance Tree Health Care Programs.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/12/abiotic-and-biotic-stress-in-low.html

Marriner, Derdriu. 19 November 2016. “Organic Amendments to Compacted Degraded Urban Highway Roadsides.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/11/organic-amendments-to-compacted.html

Marriner, Derdriu. 15 October 2016. “Tree Protection Zones by Arborists for All Construction Project Phases.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/10/tree-protection-zones-by-arborists-for.html

Marriner, Derdriu. 17 September 2016. “Stormwater Runoff Landscaping With Urban Canopy Cover and Groundcover.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/09/stormwater-runoff-landscaping-with.html

Marriner, Derdriu. 13 August 2016. “Changing Places: Tree Nutrient Movement Down, Tree Water Movement Up.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/08/changing-places-tree-nutrient-movement.html

Marriner, Derdriu. 16 July 2016. “Treated or Untreated Oriental Bittersweet Vine Management Cut-Stumping.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/07/treated-or-untreated-oriental.html

Marriner, Derdriu. 18 June 2016. “Tree Injection Site Procedures: Manufacturer's Instructions and Labels.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/06/tree-injection-site-procedures.html

Marriner, Derdriu. 22 May 2016. “Electrical Utility Area Temperate Urban Street Trees: Pruned Regrowth.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2016/05/electrical-utility-area-temperate-urban.html

Marriner, Derdriu. 16 April 2016. “Tree Injection Methods: Treatment Option in Integrated Pest Management.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/04/tree-injection-methods-treatment-option.html

Marriner, Derdriu. 6 March 2016. “Bare-Rooted Ornamental Urban Transplants: Amendments Against Mortality.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2016/03/bare-rooted-ornamental-urban.html

Marriner, Derdriu. 28 February 2016. “Bark Protective Survival Mechanisms Foil Deprivation, Injury, Invasion.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2016/02/bark-protective-survival-mechanisms.html

Marriner, Derdriu. 23 January 2016. "LITA Model: Linear Index of Tree Appraisal of Large Urban Swedish Trees." Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/01/lita-model-linear-index-of-tree.html

Marriner, Derdriu. 19 December 2015. “Tree Lightning Protection Systems: Site, Soil, Species True Designs.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/12/tree-lightning-protection-systems-site.html

Marriner, Derdriu. 24 October 2015. “Tree Lightning Protection Systems Tailored to Sites, Soils, Species.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/10/tree-lightning-protection-systems.html

Marriner, Derdriu. 15 August 2015. “Tree Friendly Urban Soil Management: Amend, Fertilize, Mulch, Till!” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/08/tree-friendly-urban-soil-management.html

Marriner, Derdriu. 13 June 2015. “Tree Friendly Urban Soil Management: Assemble, Assess, Assist, Astound.” Earth and Space News. Saturday.
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

Marriner, Derdriu. 16 August 2014. “Flood Tolerant Trees in Worst-Case Floodplain and Urbanized Scenarios.” Earth and Space News. Saturday.
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

Marriner, Derdriu. 12 April 2014. “Tree Twig Identification: Buds, Bundle Scars, Leaf Drops, Leaf Scars.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/04/tree-twig-identification-buds-bundle.html

Marriner, Derdriu. 15 February 2014. “Tree Twig Anatomy: Ecosystem Stress, Growth Rates, Winter Identification.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/02/tree-twig-anatomy-ecosystem-stress.html

Marriner, Derdriu. 14 December 2013. “Community and Tree Safety Awareness During Line- and Road-Clearances.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/12/community-and-tree-safety-awareness.html

Marriner, Derdriu. 13 October 2013. “Chain-Saw Gear and Tree Work Related Personal Protective Equipment.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2013/10/chain-saw-gear-and-tree-work-related.html

Marriner, Derdriu. 12 October 2013. “Storm Damaged Tree Clearances: Matched Teamwork of People to Equipment.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/10/storm-damaged-tree-clearances-matched.html

Marriner, Derdriu. 17 August 2013. “Storm Induced Tree Damage Assessments: Pre-Storm Planned Preparedness.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/08/storm-induced-tree-damage-assessments.html

Marriner, Derdriu. 15 June 2013. “Storm Induced Tree Failures From Heavy Tree Weights and Weather Loads.” Earth and Space News. Saturday.
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

Marriner, Derdriu. 15 December 2012. “Healthy Urban Tree Root Crown Balances: Soil Properties, Soil Volumes.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/12/healthy-urban-tree-root-crown-balances.html

Marriner, Derdriu. 13 October 2012. “Tree Adaptive Growth: Tree Risk Assessment of Tree Failure, Tree Strength.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/10/tree-adaptive-growth-tree-risk.html

Marriner, Derdriu. 11 August 2012. “Tree Risk Assessment Mitigation Reports: Tree Removal, Tree Retention?” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/08/tree-risk-assessment-mitigation-reports.html

Marriner, Derdriu. 16 June 2012. “Internally Stressed, Response Growing, Wind Loaded Tree Strength.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/06/internally-stressed-response-growing.html

Marriner, Derdriu. 14 April 2012. “Three Tree Risk Assessment Levels: Limited Visual, Basic and Advanced.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/04/three-tree-risk-assessment-levels.html

Marriner, Derdriu. 19 February 2012. “Qualitative Tree Risk Assessment: Risk Ratings for Targets and Trees.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2012/02/qualitative-tree-risk-assessment-risk.html

Marriner, Derdriu. 18 February 2012. “Qualitative Tree Risk Assessment: Falling Trees Impacting Targets.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/02/qualitative-tree-risk-assessment.html

Marriner, Derdriu. 10 December 2011. “Tree Risk Assessment: Tree Failures From Defects and From Wind Loads.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/12/tree-risk-assessment-tree-failures-from.html

Marriner, Derdriu. 15 October 2011. “Five Tree Felling Plan Steps for Successful Removals and Worker Safety.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/10/five-tree-felling-plan-steps-for.html

Marriner, Derdriu. 13 August 2011. “Natives and Non-Natives as Successfully Urbanized Plant Species.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/08/natives-and-non-natives-as-successfully.html

Marriner, Derdriu. 11 June 2011. “Tree Ring Patterns for Ecosystem Ages, Dates, Health and Stress.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/06/tree-ring-patterns-for-ecosystem-ages.html

Marriner, Derdriu. 9 April 2011. “Benignly Ugly Tree Disorders: Oak Galls, Powdery Mildew, Sooty Mold, Tar Spot.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/04/benignly-ugly-tree-disorders-oak-galls.html

Marriner, Derdriu. 12 February 2011. “Tree Load Can Turn Tree Health Into Tree Failure or Tree Fatigue.” Earth and Space News. Saturday.
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