Trees

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Overview

Trees can be incorporated into bioretention cells with other plant types, or otherwise into their own planting pits.

Performance

Tree canopies intercept and store rainfall, thereby modifying stormwater runoffThat potion of the water precipitated onto a catchment area, which flows as surface discharge from the catchment area past a specified point.Water from rain, snow melt, or irrigation that flows over the land surface. and reducing demands on urban stormwater infrastructure (Xiao et al., 1998; Xiao et al., 2000; Xiao and McPherson, 2002; Xiao et al., 2006). Canopy interceptionThe interception, storage and eventual evaporation of rainfall from vegetation canopies. reduces both the actual runoffThat potion of the water precipitated onto a catchment area, which flows as surface discharge from the catchment area past a specified point.Water from rain, snow melt, or irrigation that flows over the land surface. volumes, and delays the onset of peak flows (Davey Resource Group, 2008). The extent of interceptionThe interception, storage and eventual evaporation of rainfall from vegetation canopies. is influenced by a number of factors including tree architecture and it has been estimated that a typical medium-sized canopy tree can intercept as much as 9000 litres of rainfall year. (Crockford and Richardson, 2000). A study of rainfall interceptionThe interception, storage and eventual evaporation of rainfall from vegetation canopies. by street and park trees in Santa Monica, California found that interceptionThe interception, storage and eventual evaporation of rainfall from vegetation canopies. rates varied by tree species and size, with broadleaf evergreen trees provided the most rainfall interceptionThe interception, storage and eventual evaporation of rainfall from vegetation canopies. (Xiao and McPherson, 2002). Rainfall interceptionThe interception, storage and eventual evaporation of rainfall from vegetation canopies. was found to range from 15.3% for a small jacaranda (Jacaranda mimosifolia) to 66.5% for a mature brush box (Tristania conferta now known as Lophostemon confertus). Over the city as a whole the trees intercepted 1.6% of annual precipitationAny form of rain or snow. and the researchers calculated that the annual value of avoided stormwater treatment and flood control costs associated with this reduced runoffThat potion of the water precipitated onto a catchment area, which flows as surface discharge from the catchment area past a specified point.Water from rain, snow melt, or irrigation that flows over the land surface. was US$110,890 (US$3.60 per tree).

Planning considerations

A commonly held view is that a tree's root system will be similar to it's visible crown. For many trees, this is not the case, as roots will more often spread mush more widely, but to a shallower depth [1].

Design

Canopy interceptionThe interception, storage and eventual evaporation of rainfall from vegetation canopies.

http://www.mdpi.com/2072-4292/9/11/1202/pdf http://lfs-mlws.sites.olt.ubc.ca/files/2014/10/an_analytical_model_of_rainfall_interception_by_urban_trees.pdf https://www.nrcan.gc.ca/earth-sciences/land-surface-vegetation/biophysical-parameters/9162 https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999WR900003


Components

Inlets

Multiple methods for distribution and conveyanceMovement of water from one location to another. of runoffThat potion of the water precipitated onto a catchment area, which flows as surface discharge from the catchment area past a specified point.Water from rain, snow melt, or irrigation that flows over the land surface. into the system are recommended for redundancy and conservative designs. Combinations may be made of:

  • tree well flow,
  • catch basinsGround depression acting as a flow control and water treatment structure, that is normally dry. and distribution pipes, and
  • direct infiltration from permeable pavingAn alternative practice to traditional impervious pavement, prevents the generation of runoff by allowing precipitation falling on the surface to infiltrate through the surface course into an underlying stone reservoir and, where suitable conditions exist, into the native soil..

See also Inlets and pretreatment]

UnderdrainA perforated pipe used to assist the draining of soils.

Underdrain

Species selection

Tree species

Sortable table, click on header you wish to select tree by
Scientific Name Common Name Soil Moisture
1=Wet
2=Moist
3=Dry
Partial shade tolerance Drought Tolerance
1=Low
2=Med
3=High
Salt Tolerance
1=Low
2=Med
3=High
Pollution tolerance Compaction tolerance
Acer rubrum Red Maple
1-2
Y
2
1
Y
Y
Acer saccharinum Silver Maple
1-2
2
1-2
Y
Acer saccharum ssp. saccharum Sugar Maple
1-2
Y
2
1
Acer x freemanii Hybrid Maple / Freeman Maple
1-2
Y
2
1-2
Y
Betula papyrifera Paper Birch
2-3
2
2-3
Carpinus caroliniana American hornbeam / Blue Beech
1-2
Y
2
1
Carya cordiformis Bitter-nut Hickory
2-3
Y
2
1
Carya ovata Shag-bark Hickory
2-3
Y
3
1
Celtis occidentalis Common Hackberry
2
2
2
Y
Fraxinus americana White Ash
2
Y
1-2
2-3
Fraxinus nigra Black Ash
1-2
Y
1-2
2-3
Y
Fraxinus pennsylvanica Green Ash
1-2
2
1-2
Y
Ginkgo biloba Ginkgo
2
Y
2
2-3
Y
Y
Gleditsia tricanthos var. inermis Thornless Honey Locust
2-3
Y
3
3
Y
Y
Juglans nigra Black Walnut
2-3
Y
3
1-2
Juniperus virginiana Eastern Red Cedar
2-3
Y
3
2
Y
Larix laricina Tamarack / American Larch
1-3
Y
3
3
Liriodendron tulipifera Tulip Tree
2
Y
1
1
Picea glauca White Spruce
2
2
1
Y
Picea pungens Colorado Spruce
2
2
3
Pinus mugo Mugo Pine
2-3
Y
2
3
Pinus strobus Eastern White Pine
2-3
2
1
Platanus occidentalis Sycamore
1-2
2
1
Y
Populus balsamifera ssp. balsamifera Balsam Poplar
2
2
3
Populus deltoides Eastern Cottonwood
2
3
2-3
Y
Y
Populus grandidentata Large-tooth Aspen
2
3
2-3
Populus tremuloides Trembling Aspen
2
2
2-3
Prunus serotina Wild Black Cherry
2
2
2-3
Quercus alba White Oak
2-3
Y
3
3
Quercus bicolor Swamp White Oak
1-2
3
2-3
Y
Quercus macrocarpa Bur Oak
1-3
3
2-3
Y
Quercus muehlenbergii Chinquapin oak / Yellow oak
3
3
2
Quercus palustris Pin Oak
1-2
3
1
Quercus rubra Red Oak
2-3
2
3
Y
Salix amygdaloides Peachleaf Willow
1
1-2
3
Y
Salix lucida Shining Willow
1
1-2
3
Y
Salix nigra Black Willow
1
1
2-3
Y
Thuja occidentalis Eastern White Cedar
1-2
3
1-2
Tilia americana American Basswood
2
Y
2
1-2

Performance and research

Trees suck! (Abstracted from Phyto, by K. Kennen)

External links

In our effort to make this guide as functional as possible, we have decided to include proprietary systems and links to manufacturers websites.
Inclusion of such links does not constitute endorsement by the Sustainable Technologies Evaluation Program.
Lists are ordered alphabetically; link updates are welcomed using the form below.


  1. Crow, P. (2005). The Influence of Soils and Species on Tree Root Depth. Edinburgh. Retrieved from https://www.forestry.gov.uk/pdf/FCIN078.pdf/$FILE/FCIN078.pdf