The Benefits of Organic Mulch for Trees in the South Florida Urban Environment

Urban trees such as those present within south Florida are often stressed by their environment. Limited root space, poor soil, and lack of nutrients are common issues. While soil/foliar testing, root zone excavation, and fertility programs are encouraged, there are simpler ways to improve overall tree health. One of the most cost-efficient and effective ways to achieve this is mulching.

Mulch is simply defined as a substance which covers soil. Mulch comes in organic (wood chips, pine straw, leaves) and inorganic forms (rubber, landscape fabric, rocks). While both forms of mulch may help to retain soil moisture, reduce weed competition, and reduce soil temperatures, organic forms of mulch have greater benefits.

The most overlooked benefit of organic mulch in the urban landscape is its ability to improve the soil it is applied to. When mulch is applied to a typical sandy South Florida soil, for example, its immediate benefits are reducing erosion, dust, and water runoff. The long-term benefits are surprisingly far-reaching. When mulch breaks down, it adds organic matter to the soil. Over time, this simple amendment can increase soil fertility, water-holding capacity, reduce bulk density, and increase beneficial microbes. Basically, this helps improve the overall quality of the soil and provides a natural buffer to sudden changes that would otherwise impact tree health.

When assessing overall tree health, soil is of upmost importance. When the soil is healthy, overall tree health is greater, and the ability of the tree to ward off pests and diseases may increase. Mulch is an accessible, affordable, and relatively easy way to contribute to long-term soil health.

In the landscape, weeds and turf grass often compete with a tree’s critical root zone for water, nutrients, space, and light. Sod also has different fertility and water requirements than most canopy trees and palms.  For these reasons, it is recommended that tree owners remove sod underneath the dripline of the tree prior to mulch application. Removing sod will also reduce excess fertilizer and water use. Organic mulch may then be applied to a depth of 2-3 inches. Take care not to bury the tree trunk or major buttress roots (this often leads to rot) and keeping the mulch at least 6-12” away from the trunk is also recommended. Depending on the specific type of mulch used and site conditions, older mulch may be raked and replaced seasonally to increase aeration. These simple adjustments can reduce maintenance and costs for the tree owner and contribute to the overall health of our urban forest. 

For additional information about the tree benefits of mulch and organic matter please click here SL273/MG454: Soils and Fertilizers for Master Gardeners: Soil Organic Matter and Organic Amendments (ufl.edu).  (Guest Post by Kirstie McCullough, ISA Certified Arborist) 

                                                How to Properly Apply Mulch

 

Photo Credit: Https://greentreedoctor.com  

Trees and the Asian Subterranean Termite

There's a new pest affecting south Florida hardwood trees, the Asian Subterranean termite. Trees weakened by termite activity are more likely to fail during hurricane and high wind events, potentially causing considerable damage to people and property. Rapid tree decline, failure and death are common indicators of termite infestations. Due to the typically large size of the colony, 24 hour feeding cycle and the ability of the termites to penetrate concrete they can cause substantial damage to building and trees alike.

Tree hosts for this particular termite are varied and currently include but are not solely limited to Sabal Palm, Live Oak, Laurel Oak, Gumbo Limbo and Slash Pine trees. Typically this termite swarms between the months of February and April in Florida, so be aware of any swarming activity you see near your trees and property especially during this time. Currently the only effective treatment method is through the use of bait stations to eliminate the entire colony.  For additional information please visit the following University of Florida website.

Termite Colony Snapshot

Image used courtesy of morningagclips.com

Termite caused damage to wood structure.

Image used courtesy of palmbeachcivic.org

Termite damage present on a mature Live Oak Tree.

Image used courtesy of Twitter user @Chouvencl

South Florida Palms and Lethal Bronzing

There's a new palm disease to be aware of called Lethal Bronzing that can potentially impact some of our most prestigious south Florida. Common symptoms include premature fruit drop (fruit is stunted, brown and or dead along with dead inflorescences), gradual browning of older leaves, then death of young/new fronds and eventually spear leaf death (center most frond growth point). While costly preventative measures are available unfortunately, there is no cure for infected palms and the only course of action once a palm is confirmed as infected is total removal. If you suspect a palm may have Lethal Bronzing please contact the local Broward County Cooperative Extension Service for additional advice and potential testing. Additional information about Lethal Bronzing can be found at the following IFAS website.

 Necrotic lower Sabal Palm fronds and dead spear leaf. (c) The Daytona Beach News Journal 

Canary Palm almost completely dead with spear leaf dying (c) Fox 13 News

Premature fruit drop and necrotic inflorescences of Coconut Palm. (c) The Florida Alligator

Annie Beck Memorial Tree

In early 1930, Fort Lauderdale resident and pioneer Ms. Annie Beck planted a tree seedling in front of her home, growing into what has become a cherished local treasure. Her Silver Trumpet tree (Tabebuia caraiba) has provided years of enjoyment with its golden floral displays and corky-textured bark. Over the course of our seasonal history, this tree survived many hurricanes and a few environmental challenges. But, it may not have withstood the pressures of redevelopment without the help of the Fort Lauderdale Garden Club (originally founded by Ms. Annie Beck in 1927) who sought out a new and permanent home for this historic tree.

In November of 1997, ISA Certified Arborist and local landscape architect L.Thomas Chancey was hired to oversee the tree relocation project. Because of the tree’s age, species, condition and the existing soil characteristics, this project proved to be a worthy challenge.

From November of 1997 through June of 1998, manual root pruning was first performed in segments over a seven-month time period. Root pruning was an important step in making sure that the roots had adequate time to begin regenerating prior to relocation. In order to avoid any further root damage, it was also necessary to gradually remove existing coral rocks that had embedded over time into the tree’s roots. A tree protection fence was also installed around the tree’s dripline to protect the tree from ongoing construction activities.

Finally, on July 25, 1998 the tree was successfully transplanted using a large crane. A steel rod was drilled into the tree trunk and straps wrapping the roots were attached to it. The crane then lifted the secured tree and moved it to its new, permanent home on the NE corner of Bubier Park located at 32 E Las Olas Blvd in Fort Lauderdale. From that day forward, this iconic Silver Trumpet tree is affectionately referred to as The Annie Beck Tree. Original news article concerning the tree’s move is available here.

Today, the Annie Beck Tree continues to thrive, boldly showcasing its spectacular flower display and unique trunk structure, much to the pleasure and amazement of City of Fort Lauderdale neighbors and delighted out-of-town guests.

 Tree being relocated by crane July 25, 1998.

 Fort Lauderdale Garden Club members Rose Bechard-Butman & Ann Schandelmayer by the tree July 25, 1998.

ISA Certified Arborist and local landscape architect L. Thomas Chancey visiting the tree April 23, 1999.

Annie Beck Tree Today

Fort Lauderdale's Bicentennial Liberty Live Oak Tree (Revision)

The City of Fort Lauderdale’s Bicentennial Liberty Live Oak tree, located adjacent to the Riverwalk area within Bubier Park, is approaching 250 years and I recently uncovered a trove of information and photographs documenting the tree’s relocation, providing a unique look into the past.

Live Oak Tree: September 1976

The live oak tree was donated to the City by Judge Robert O’Toole in early 1976 at over 200 years old. It was originally located near southeast 1^st avenue and southeast 6^th street in downtown Fort Lauderdale. The tree weighed over 50 tons and had a height of 30-35 feet and an average spread of 50-feet. Its relocation was considered to be the largest successful bare-root transplant of a tree in the world at that time.

The City’s then Urban Forester, Mike Moore, coordinated the relocation and preservation of the live oak tree. It had to be root pruned and braced before transport. The project was a massive undertaking and required coordination from multiple entities including the Florida Forest Service, FPL, Eller Company, Powell Brothers and Koch Towing Company. At one point, the City’s Fire Department was also called in to help free the tree roots from coral rock after a cable snapped during transport. After five months of preparation, over 40 personnel, a flatbed truck, and river barge along with three broken 155 ton steel cables the tree was successfully relocated on September 8, 1976.

On June 27, 1978, the live oak tree was renamed the Bicentennial Live Oak Tree as part of the dedication for the Robert H. Bubier Memorial Park. It was later renamed the Bicentennial Liberty Live Oak Tree, with installation of an official plaque, at a ceremony on September 11, 2002 in remembrance of the September 11, 2001 horrific events. Disney World’s Liberty Tree served as the original inspiration for the plaque dedication and wording as authored by Doug Eagon of the Stiles Corporation.

Today the Bicentennial Liberty Live Oak Tree is still doing fairly well at almost 250 years. Significant work was done to improve the tree’s overall health and vitality after impacts from a storm in August 2017. With such a historic past, the City will continue ongoing tree management efforts to preserve the tree well into the future!

Live Oak Tree: September 1976

Bicentennial Liberty Live Oak Tree Today

Hurricanes, Storms, and Your Landscape

As we are in the middle of hurricane season I am reposting an article I co-authored with my good friend Mark Torok from the Florida Forest Service (FFS) tackling the tough questions around tree care and storms.

Hurricanes, Storms, and Your Landscape

by

Mark Torok, FFS Senior Forester

Mark Williams, Treemendous Consulting Group

Living in Florida, sooner or later, given its history, your landscape is going to be exposed to high winds either from a hurricane, tornado or a storm. So what can be done to minimize wind damage in your Florida landscape?

 

For starters, have your existing trees inspected annually and/or structurally pruned by an ISA (International Society of Arboriculture) certified arborist who is also licensed and insured. To find an ISA certified arborist in your area, you can use the “Arborist Search” on the ISA website at http://www.isa-arbor.com/findanarborist/arboristsearch.aspx. Having your trees inspected annually (risk assessment) and structurally pruned every 2-5 years will help the trees become more wind-resistant by eliminating or minimizing structural defects such as cross branching, decay, codominant stems, deadwood and included bark in the trees.

 

If you are thinking about redoing and or enhancing your landscape, plant more wind resistant trees. Just like people, all trees are not the same; some are more wind-resistant than others. In general, trees species that are wind resistant are also good compartmentalizers. Good compartmentalizers are tree species that can recover well from wounds and that seal them off effectively preventing the spread of decay. Even trees that are in the same family can vary on how well they compartmentalize. For example, live oak trees are very wind resistant and great compartmentalizers while laurel oaks/water oaks are very poor compartmentalizers and not very wind resistant trees.

 

Another way to make your landscape more wind tolerant is planting trees in groups. In a natural forest setting, winds normally blow over a stand of trees instead of blowing through them unlike the total exposure faced by an individual, open-grown tree. Grouping trees together in tree islands/communal plantings simulates how trees grow naturally and mimics the buffering effect of trees within a natural forest community. But remember to use minimum tree spacing requirements which are typically planting trees at least 15-20 foot on center for tree species that develop large canopy crowns. In order for a tree to develop proper taper a certain amount of wind exposure is also necessary. Some examples of Florida native tree species that are often found growing in groups include slash pine, bald cypress, live oak and sabal palm.

 

Addressing any root defects that may be present before planting will also aid tree establishment and help ensure a well anchored root system.  Some additional information about tree root pruning is available at: (http://hort.ifas.ufl.edu/woody/roots.shtml). Remember to plant your tree slightly above grade, install the recommended bracing system and to remove any circling, plunging and girdling roots that are present. The use of Florida Grade No. 1 (Grading Standard for Nursery trees set by FDACS) or above rated trees is also recommended as these trees are of high quality with excellent structure. Trees of this grade typically have greater vigor, establish faster and are free of structural defects commonly present on poorer quality/lower grade trees. Some additional information on proper tree planting and bracing is available at: ( http://hort.ifas.ufl.edu/woody/planting2.shtml).

 

 

Here are some high wind resistant native south Florida trees:

 

Gumbo limbo              Green buttonwood     Geiger tree

White stopper             Redberry stopper        Spanish stopper

Lignum vitae                Dahoon holly                Krug’s holly

Black ironwood           Bald cypress                   Pond cypress

FL silver palm              Cabbage/Sabal palm   FL thatch palm

Key thatch palm          Myrtle oak                     Live oak

Sand live oak

Here are some medium-high wind resistant native south Florida trees:

 

Pond apple                    Satinleaf                        Royal palm

Pigeon plum                  Wild tamarind             Sweetbay magnolia

Mastic tree                    Paradise tree               West Indian mahogany

 

References

Duryea, M.L. 2008. Trees and Hurricanes. Website: http://hort.ifas.ufl.edu/treesandhurricanes/index.shtml of the University of Florida Cooperative Extension Service. Gainesville, FL.

 

Gilman, E. 2005. Tree selection for landscapes. Website with 680 Tree Fact Sheets: http://hort.ifas.ufl.edu/woody/planting/TreeSelectionIntroduction.htm of the University of Florida Cooperative Extension Service. Gainesville, FL.

 

Crawford, P. 2005. Florida Gardening Series, Volume 3 – Stormscaping: Landscaping to Minimize Wind Damage in Florida. Color Garden Inc. Canton, GA. 168 pp.

Trees and Wildfires

Trees face many challenges including pressure from overdevelopment, climate change, exotic pests/diseases, storms etc.. One of the most noticeable environmental challenges is wildfire. Fires are often created in nature due to drought conditions and lightning strikes. Fires can also be caused indirectly from human activities and something as small as a flicked cigarette butt in the wrong place can cause a devastating fire.
While fires can be disruptive and dangerous certain species of trees have evolved to tolerate and in some cases require periodic fire events to reproduce and thrive. The US Forest Service along with many State forestry agencies routinely conduct controlled burns to help eliminate undergrowth and improve the health of forests. The National Forest Foundation further discusses how trees thrive and survive in fire prone areas.

Image used courtesy of Mike McMillan/Spotfire Images

Image used courtesy of the Government of Alberta