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Publication #EES42

Enviroscaping to Conserve Energy: Trees for South Florida1

Timothy K. Broschat, Alan W. Meerow and Robert J. Black2

Introduction

Residential energy use comprises about 26% of all the energy used in the state of Florida (Florida Energy Office, 1992). In south Florida, about 35% of this annual residential energy expenditure is for cooling the home during Florida's 5- to 7-month-long summer, and about 10% is used for heating in winter (Cook, 1993). As utility rates escalate, so does the cost of staying comfortable in the home.

Glass windows and doors can account for between 30 and 60% of a building's total heat gain in the summer (Cook, 1986). As much as 270 Btu (heat unit called British thermal unit) of direct and diffused solar radiation can enter a home or building through each square foot of glass on the east and west sides. For example, if sunlight strikes only 50 square feet of a clear glass window (sliding-glass door) on a west wall, the cooling effect of more than one ton of air conditioning is required to remove the heat gained from this source alone. This is more than eight times the heat gain caused by conduction and infiltration. Even windows facing north or south can have twice as much indirect radiant heat gain than that from conduction and infiltration combined.

Before central heating and air conditioning, homes were designed and built to take advantage of natural heating and cooling. For example, a tree with high branches offers shade in the summer and insulation from cold winter winds. Today, passive methods of climate control are once again of interest because we are now aware of fossil fuel supply limitations and the environmental effects of fossil fuel use. New information has substantially improved many passive, energy-saving landscaping concepts (known as enviroscaping) from the past.

Landscape plants can improve the appearance of our surroundings and modify the extremes of local climate (microclimate modification). Plants provide shade, insulate the home from heat loss or gain, and cool the air that surrounds their leaves through transpiration (release of water from plant pores).

Trees are the main types of landscape plants used around the home for passive energy conservation. They provide shade, influence air movement around the house and, once established, require little maintenance. The energy-conserving impact of a particular tree species depends on 1) whether it keeps its leaves during the winter and 2) the shape of a tree and density of its foliage.

Planting Site Selection

House walls are the most practical to shade because new tree plantings take many years to cast an effective shadow on the roof. Heat transmitted through the roof is best reduced by using attic insulation, radiant barriers and ventilation. This is because tree limbs over the roof can present both a nuisance (litter clogging rain gutters) and a risk of damage or injury should heavy limbs fall off in a storm. Existing vegetation that can provide roof shade without undue risk, however, should be incorporated into the home site design.

The correct placement of trees shading the home involves consideration of the angle of the sun's rays in summer and winter, mature tree height and structure height. In general, the target areas for shading during Florida's warm months are the walls on western, eastern and southern exposures, in that order. Though an exposure facing due south receives little direct sun on June 21, by August the sun is low enough in the sky to increase heat loads considerably on south walls. Windows provide the most direct entry for heat into the home. Consequently, special attention may need to be given to walls containing the most windows.

The benefits of new shade trees should be felt within 5 years. To accomplish this goal, a distance of 7 to 20 feet from tree to wall is recommended. Lot size and the mature tree height directly influence this distance. The closer a tree is to the house, the longer its shading effects last during the day. The shadow of a tree planted 10 feet from the home moves across the shaded surface four times slower than a tree planted 20 feet away.

If winter windbreak effects are desired, trees should be planted on the north and northwestern exposures of the home. This is the prevailing direction of blustery, winter winds in most of Florida (see EES-5 Florida Climate Data ). The effects of summer breezes, which usually prevail from the southeast and southwest in Florida, are often desirable during mild, transitional times of the year. Where air conditioning exclusively cools the home for most of the hot season, summer winds can reduce cooling efficiency by increasing hot, humid air infiltration around window and door fittings or cracks in siding and masonry. In this case, a tree windbreak located on the southeast exposure of the house deflects the energy-robbing winds from the home.

Tree Selection

The chart at the end of this publication provides information that will help you choose one or more species best suited to your house and landscape. The trees are alphabetized by scientific name. The size category specifies the mature height of the tree (small, small-medium, medium, medium-large, and large).

If shade requirements are immediate, give careful attention to the growth-rate designation in the chart. A fast-growing tree increases in height by 3 or more feet per year and provides shade benefits within 5 years. Most fast-growing trees, however, are both short lived and weak wooded, two undesirable characteristics. In such cases, it may be desirable to plant both a small, rapidly growing tree and a moderate or slow-growing species nearby. The fast- growing tree could then be removed once the other species provides shade benefits.

Site conditions directly influence the establishment and the life of a landscape tree. Coastal residents should heed the salt-tolerance ratings of the listed species. The "General Comments" column on the chart givesspecific tolerances (or intolerances) of a particular species. Tailor your choices to match the conditions in your site. For instance, a tree requiring well-drained soils does not prosper where standing water accumulates after a heavy rain. If this condition applies to your home site, choose trees for wet-soil tolerance as indicated (e.g., red maple, Acer rubrum; pond apple, Annona glabra; and bald cypress, Taxodium distichum).

Relative drought tolerance is also indicated for each species. These ratings refer to Florida conditions only and should be interpreted as follows: High -- survives without supplemental irrigation after establishment; Moderate -- requires supplemental irrigation during very dry periods to maintain satisfactory appearance and health; and Low -- little or no drought tolerance. Drought tolerance also varies with soil type, water table, and other environmental conditions.

Whether a tree is evergreen or deciduous ("Leaf Persistence" on the chart) affects its performance. Deciduous trees, which drop their leaves in winter, are recommended for use on south, southeast and southwest exposures. In summer, they provide desired shade. In winter, their bare canopy allows the sun's rays to warm the home, creating additional energy savings. On the other hand, evergreen trees, which have leaves all year, on the north and northwest exposures provide the most effective barrier to cold, winter winds.

The shape of a tree influences how long shade lasts. Spreading, round and vase-shaped canopies provide the longest periods of shade during the day. With attention to both this category and the shade-density rating, home-shading methods can be fine tuned to meet individual needs and desires.

Interest in native plant materials has increased greatly in the state, so all native species are marked with an asterisk (*) on the chart. In some cases, native plants may be better adapted than exotic species to local soil and weather conditions.

A few common landscape trees in south Florida are not on this list. Australian pine (Casusarina equisetifolia), punk or cajeput tree (Melaleuca quinquenervia), earleaf acacia (Acacia auriculiformis), carrotwood (Cupaniopsis anacardioides), ear tree (Enterolobium cyclocarpum), bishopwood or toog (Bischofia javanica), laurel fig (Ficus microcarpa), and Brazilian pepper (Schinus terebinthifolius) are exotic species that are considered invasive, or have other serious environmental problems such as invasive root systems. These species are not recommended for south Florida landscapes.

Planting and Maintenance

All new tree plantings benefit from soil preparation, regular irrigation, and, in some cases, protection from insects, disease or weather extremes. Young trees require a period of regular aftercare to ensure proper establishment. Knowledgeable nursery employees and county extension agents are good sources for answers to individual problems.

Detailed information on proper tree placement, shading patterns, and microclimate modification are in the following publications available at your county extension office:

EES 43 Enviroscaping to Conserve Energy: Microclimate Modification

EES 49 Enviroscaping to Conserve Energy: Determining Shade Patterns for North Florida

EES 50 Enviroscaping to Conserve Energy: Determining Shade Patterns for Central Florida

EES 48 Enviroscaping to Conserve Energy: Determining Shade Patterns for South Florida

References

Cook, Gary. 1986. A guide to selecting window and glazing options for Florida buildings. IFAS/Florida Energy Extension Service EES-36. Gainesville, FL.

Cook, Gary. 1993. Personal communication. Gainesville, FL.

Florida Energy Office. 1992. Florida energy data report: 1970-1990. Dept. of Community Affairs, Florida Energy Office, Tallahassee, FL.

Key to South Florida Tree Chart

  • Leaf Persistence: D = Deciduous, E = Evergreen, S = Semi-Evergreen

  • Form: C = Columnar, O = Oval, P = Pyramidal, R = Round, S = Spreading, V = Vase-Shaped

  • Growth Rate: S = Slow (less than 6 inches per year), M = Moderate (6 inches to 3 feet per year), F = Fast (more than 3 feet per year)

  • Shade Density: L = Light, M = Medium, H = Heavy

  • Size: S = Small (up to 25 feet), M = Medium (25 - 40 feet), L = Large (more than 40 feet)

  • Drought Tolerance: L = Low, M = Moderate, H = High

  • Salt Tolerance: L = Low, M = Moderate, H = High

Tables

Table 1. 

Tree Selection for South Florida

Scientific Name

Common Name

* = native

Leaf Persistence

Form

Growth Rate

Shade Density

Size

Drought Tol.

Salt tol.

General Comments

Acer rubrum

Red maple

D

O-R

F

M

M

M

L

Tolerates wet soils. Red flowers and fruit in late winter/early spring.

*Annona glabra

Pond apple

D

R

M

M

S

L

M

Tolerates wet sites.

Araucaria heterophylla

Norfolk Island pine

E

C-P

M

M

M-L

H

M

Tends to drop branches in high winds.

Averrhoa carambola

Carambola

E

R

M

M

S

M

L

Edible fruit; can be messy.

Bauhinia x blakeana

Hong Kong orchid tree

S

R

F

H

M

H

M

No messy fruits. Long season of bloom.

Bixa orellana

Annatto

E

R

M

M

S

M

L

Requires wind protection. Attractive flowers and fruit; fruit a source of natural dye.

Bombax ceiba

Red silk cotton tree

D

R

M

M

L

H

L

Red or orange-red flowers in winter. Spiny trunk and branches.

Bucida buceras

Black olive

E

R

M

M

M-L

H

H

Seed-grown stock variable in many characteristics.

Bulnesia arborea

Vera wood

E

R

M

H

M

H

M

Yellow flowers in summer. Weak-rooted.

*Bursera simaruba

Gumbo limbo

D-E

R

M

M

M

H

H

Attractive form and red peeling bark.

Butea frondosa

Flame of the forest

D

S

S

M

M

M

M

Spectacular orange flowers; Requires fertile soil.

Caesalpinia granadillo

Bridal veil tree

E

V-S

M

L-M

M

M

L

Attractive bark. Lacy foliage. Very hard wood.

Callistemon citrinus

Lemon bottlebrush

E

O

M

M

S

H

M

Red bottlebrush flowers in spring. Tolerates moist sites.

Callistemon viminalis

Weeping bottlebrush

E

R

M

M

S

H

M

Weeping habit. Attractive red bottlebrush flowers.

Calophyllum brasiliense

Beauty Leaf

E

R

M

H

M

M

H

Glossy foliage. Flood tolerant.

Canaga odorata

Ylang-ylang

E

O

F

M

M

M

L

Extremely fragrant flowers.

Cassia bakeriana Pink cassia

D

R

M

M

M

H

L

Showy pink flowers. Soft velvety light green foliage

Cassia fistula

Golden shower

D

O

F

M

M

H

M

Bright yellow flowers. Seed pods messy.

Cassia javanica

Apple blossom cassia

D

R

F

M

M

M

L

Showy pink and white flowers.

Chorisia speciosa

Silk floss tree

D

R

M

L-M

L

H

L

Thorny trunk. Surface roots. Can be messy.

*Chrysophyllum oliviforme

Satinleaf

E

R

M

M

S-M

H

H

Attractive foliage. Excellent accent tree.

*Citharexylum fruticosum

Fiddlewood

E

O

S

M

S

H

M

Small, white, fragrant flowers.

*Coccoloba diversifolia

Pigeon plum

E

O

M

M

S-M

H

H

Interesting bark. Good accent or specimen tree.

*Coccoloba uvifera

Sea grape

E

S

M

M

S

H

H

Superb seaside tree. Edible fruit. Attractive bark.

Cochlospermum vitifolium

Buttercup tree

D

O

F

M

S-M

H

M

Large yellow flowers.

*Conocarpus erectus

Buttonwood

E

O-R

F

M

M

H

H

Can be used as a screen or hedge.

*Conocarpus erectus var. sericeus

Silver buttonwood

E

R

M

M

S

H

H

Silver-leafed form of species. Stays smaller than typical variety.

Cordia boissieri

White Geiger

E

R

M

M

S

H

M

Showy white flowers.

*Cordia sebestena

Geiger tree

E

R

M

M

S

H

H

Bright orange flowers most of the year. Often defoliated by insects.

Delonix regia

Royal poinciana

D

S

F

M-H

M-L

H

H

Spectacular red flowers. Brittle wood. Large, woody fruits are messy.

Eriobotrya deflexa

Bronze loquat

E

R

M

M

S

H

M

Attractive bronze or red new growth.

Eriobotrya japonica

Loquat

E

R

M

M

S

H

M

Edible fruit. Host for Caribbean fruit fly.

Erythrina spp.

Coral trees

D

C-S

F

L

M-L

H

H

Showy red flowers. Seeds toxic. E. indica and several other species do well in Florida.

Eucalyptus torelliana

Torrelliana eucalyptus

E

O

M

L

M

H

H

Smooth green bark.

*Eugenia spp.

Stopper trees

E

O

M

M

S

H

M

Several native species available. Aromatic foliage. Edible fruit.

*Ficus aurea

Strangler fig

E

V-R

F

L

M-L

H

M

Often scraggly. Not as aggressive as many exotic fig species, but needs adequate space.

*Ficus citrifolia

Shortleaf fig

E

S

M

M

M-L

H

M

Few aerial roots.

Ficus lyrata

Fiddleleaf fig

E

R

M

M

M

H

M

Much less aggressive than other figs. Large leaves can be messy.

Ficus religiosa

Sacred fig

E

R

M

M

M

H

M

Quaking aspen-like quality to leaves.

Ficus rubiginosa

Rusty fig

E

R

M

H

M

H

L

Rusty undersides on leaves.

Filicium decipiens

Fern tree

E

R

M

H

M

M

M

Fine, fern-like foliage.

Guaiacum officinale Lignumvitae

E

R

S

M

S

H

H

Showy blue flowers.

*Guaiacum sanctum Native Lignumvitae

E

R

S

L

S

H

H

Showy blue flowers and fine textured foliage.

Harpullia arborea

Harpullia

E

R

S

M

S

H

H

Ornamental fruits and seeds.

*Ilex cassine

Dahoon

E

O

M

L

S

M

M

Best in moist soils. Attractive red fruits on female plants.

Jacaranda mimosifolia

Jacaranda

D

R

F

L

M

H

L

Purple flowers in spring. Ferny foliage. Brittle branches.

Juniperus virginiana silicicola

Southern red cedar

E

P-O

M

M

S-M

H

H

Very fine textured foliage.

Kigelia pinnata

Sausage tree

E

R

M

M

M

H

M

Novelty tree for its large, dangling flowers and fruits. Messy.

Krugiodendron ferreum

Black ironwood

E

O

S

M

S

H

H

Very dense wood.

Lagerstroemia indica

Crape myrtle

D

O

M

M

S-M

H

L

Many sizes and flower colors available.

Lagerstroemia speciosa

Queen crape myrtle

D

R

F

H

M-L

H

L

Very showy flowers. Attractive long-lasting fall color.

Litchi chinensis

Litchi

E

R

M

H

M

M

L

Delicious fruit. Handsome shade tree. Several cultivars.

*Lysiloma latisiliqua

Wild tamarind

E

R

M

L

M

H

H

Very fine leaf texture. Tolerates seaside locations.

Lysiloma sabicu

Sabicu

E

V-S

M

L

S

H

H

Flat-topped tree with weeping branches.

Macadamia integrifolia

Macadamia nut

E

R

S

H

S-M

H

L

Several cultivars. Nut production erratic in Florida.

Mangifera indica

Mango

E

R

M

H

S-M

H

M

Delicious fruit can be messy. Attractive new leaves.

Manilkara roxburghiana

Mimusops

E

R

M

H

M

H

H

Edible fruit.

*Mastichodendron foetidissimum

Mastic tree

E

R

S

H

M

H

M

Edible fruit. Attractive leaves.

Murraya paniculata

Orange-jasmine

E

R

M

M

S

H

M

Fragrant white flowers throughout the year. Often shrubby.

Noronhia emarginata

Madagascar olive

E

O

M

M

S

H

H

Tough, seaside specimen.

Pachira aquatica

Guiana chestnut

E

O

M

L

M

M

L

Showy, brush-like flowers.

Peltophorum pterocarpum

Yellow poinciana

D

V

M

L

M

H

H

Showy yellow flowers. Can topple in strong winds.

Persea americana

Avocado

E

R

F

M

M

M

L

Edible fruit. Brittle wood. Susceptible to laurel wilt disease.

Persea borbonia

Red bay

E

O

M

M

M

H

H

Tolerates wet sites. Susceptible to laurel wilt disease.

*Pinus clausa

Sand pine

E

O

M

L

M

H

L

Persistent cones. Picturesque leaning or twisted habit when old.

*Pinus elliottii

Slash pine

E

O

F

L

L

H

M

Straight trunk.

*Piscidia piscipula

Jamaican dogwood

D

S

F

M

M

H

H

Attractive pink flowers in spring.

Podocarpus gracilior

Weeping podocarpus

E

O

M

M

M

M

L

Attractive weeping branches.

Podocarpus macrophyllus

Podocarpus

E

C

M

M

M

H

M

Low branching. Intolerant of flooding.

Pongamia pinnata

Pongam

S

R

M

H

M

H

M

Leaves and pods can create litter problems.

Pseudobombax ellipticum

Shaving brush

D

S

M

M

S

M

M

Spectacular pink flowers when leafless. Reddish new foliage.

*Quercus laurifolia

Laurel oak

E

O-S

F

H

L

H

L

Tend to be short-lived.

*Quercus virginiana

Live oak

E

S

M

H

L

H

H

Old trees very picturesque. Long-lived.

Senna polyphylla

Desert cassia

E

R

M

M

S

H

M

Showy golden flowers year round.

Senna surattensis

Glaucous cassia

E

R

M

M

S

H

M

Showy golden flowers year round.

*Sapindus saponaria

Soapberry

D

R

M

M

M

H

H

Soap-like compound derived from fruits. Fruits can be messy.

*Simarouba glauca

Paradise tree

E

R

S

L

M

H

L

Glossy dark green leaves.

Spathodea campanulata

African tulip tree

S

O

M-F

M

M

H

M

Showy orange flowers. Weak-wooded.

*Swietenia mahagoni

West Indian mahogany

S

R

M

M

M

H

M

Woody fruits can be messy.

Insects may cause defoliation in the spring.

Swietenia macrophylla

Big-leaved mahogany

E

O

M

M

L

H

M

Taller, more upright form than S. mahagoni.

Tabebuia caraiba

Silver trumpet tree

D

O

M

M

S-M

H

M

Irregular crown. Silvery leaves. Large yellow flowers. Weak-wooded.

Tabebuia chrysotricha

Golden trumpet tree

D

R

M

L

S

H

M

Yellow flowers. Sparse canopy.

Tabebuia heterophylla

Pink trumpet tree

E

O

M

M

S

H

M

Pink flowers. Fine street tree. Thrips a problem.

Tabebuia impetiginosa

Purple tabebuia, Ipe

D

R

M

M

S

H

M

Pink-purple flowers.

Tamarindus indica

Tamarind

S

R

M

M

M

H

H

Handsome form. Wind resistant. Edible fruits can be messy.

*Taxodium distichum

Bald cypress

D

P

M

L-M

L

H

L

No serious pests. Very tolerant of both wet and dry soils.

*Tecoma stans

Yellow elder

E

R

F

M

S

H

M

Yellow flowers most of the year. Often shrubby. Weak-wooded.

*Zanthoxylum fagara

Wild lime

E

R

M

M

S

H

M

Thorny. Takes coastal conditions well.

Footnotes

1.

This document is Circular EES-42, formerly Landscaping to Conserve Energy: Trees for South Florida, Florida Cooperative Extension Service, UF/IFAS Extension. Publication date July 1993. Reviewed August 2010. Revised August 2013. Please visit the EDIS website at http://edis.ifas.ufl.edu/.

2.

Timothy K. Broschat, pProfessor, Alan W. Meerow, former professor, Fort Lauderdale Research and Education Center; Robert J. Black, former associate professor, Environmental Horticulture Department, UF/IFAS Extension, Gainesville, FL 32611. The Florida Energy Extension Service receives funding from the Florida Energy Office, Department of Community Affairs and is operated by the University of Florida's Institute of Food and Agricultural Sciences through the Cooperative Extension Service. The information contained herein is the product of the Florida Energy Extension Service and does not necessarily reflect the views of the Florida Energy Office.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.