Transplanting trees: the four methods A300 Part 6 names, and what extension services say about tree spades and palms

This page reports what the named sources say. It is not a how-to. Planting depth and the other planting rules cities write are on planting and soil standards and planting specs compared by city. Crane lifts of large trees are covered in cranes in tree work.

What A300 Part 6 covers

The Tree Care Industry Association's page for ANSI A300 Part 6, Planting and Transplanting, says the part applies to planting and transplanting trees, shrubs, palms and other woody plants. The standard itself is sold, so this page does not reproduce its clauses. The association's page lists the subjects Part 6 addresses: plant and site inspection, timing of transplanting, determining root ball size, digging trees and shrubs, transplanting, lifting, moving and storage, digging the planting hole, planting woody plants, planting container stock, specific palm standards, and post-planting care.

The page says the A300 transplanting standards recognize four basic methods.

Method	How the TCIA page describes it	Extra detail from other sources
Balled and wrapped	Plants dug from the ground with the soil left around their roots as a ball, which is then bound.	Not published on the page.
Bare root	Plants lifted and then stripped of the soil or growing medium around the roots.	Not published on the page.
Boxed	A way of protecting roots in which a trench is dug and a box is built around them, and the box is used to lift, carry and set the plant.	Not published on the page.
Tree spade	Machinery that moves large trees.	The North Dakota State University newsletter in the next section.

The page also carries an advisory notice. It says the correct planting depth is based on locating the trunk flare and making sure the bottom of the flare is at finish grade when the operation is done.

Tree spades: the May 2005 North Dakota State University newsletter

Tree Talk, volume 1 issue 2, May 2005, carries an article by Steve Sagaser, an extension agent in Grand Forks County. It is a 2005 extension newsletter and is reported here as dated. The article says tree spades came into use in the late 1960s. Before them, two people digging by hand could spend a full day moving two trees of 3 to 4 inch caliper, and the machine cut that to minutes.

On utilities, the article calls locating underground utilities before digging an absolute necessity. It names phone, cable television, gas and power lines as the most common, and adds sprinkler lines and septic systems. It says tree moving contractors can be held liable for damages, and that the booms on most tree spades need safe clearance from overhead power and phone lines.

On size, the article says a tree's size is judged by trunk caliper, measured about 6 inches off the ground for trunks 4 inches or less and about 12 inches off the ground for larger trunks. It warns that a spade able to lift a tree is not necessarily big enough to dig enough soil and roots. It says manufacturers rate their machines differently, but that generally the spade diameter should be 10 times the trunk caliper, and it prints a table of typical manufacturer recommendations.

Tree spade size	Maximum trunk caliper in the newsletter table
30 inches	3 inches
40 inches	4 inches
60 inches	6 inches
90 inches	9 inches
105 inches	12 inches
125 inches	14 inches

The article adds that trees with wide shallow roots, poplars as its example, lose a higher share of roots than deep-rooted trees, and that oaks with a deep taproot are much harder to dig. It says moving a tree larger than the machine is rated for raises root loss sharply. It also says nursery trees that have been root pruned are better candidates than wild-grown ones, and that spruce and pine should not be moved in spring while sending out new growth.

Palms as a separate case: University of Florida extension

The University of Florida (UF/IFAS) publication EP001, Transplanting Palms in the Landscape, by Timothy K. Broschat, says palms are relatively easy to move compared with broadleaf trees of similar size. It gives the reason as root structure: broadleaf trees have a few large primary roots from the trunk base, while palm roots are all adventitious and keep starting from a root-initiation zone at the base of the trunk, with each root staying the same diameter.

The publication reports trials showing species differ. When the roots of Sabal palmetto were cut, virtually all cut roots died back to the trunk and were replaced by new roots, so cut distance did not matter. For coconut palm about half of cut roots survived. It reports that among 340 juvenile palms of 17 species with their roots cut off, none made a new root, whereas trunked specimens of two of those species survived. For most palms in Florida, it says planting in the rainy season, June to November, raises survival, and that in a Mediterranean climate such as California other authors recommend the warm dry months of May to July.

The same publication says container-grown palms do not need wrapping roots cut, unlike broadleaf trees. It also reports a study of four mycorrhizal or microbial products on transplanted palms that found no benefit over proper fertilization alone.

Where the sources do not agree or are silent

The TCIA page gives no root ball size ratio, and the sold standard is the place for it. The newsletter gives a spade-to-caliper rule of thumb from 2005 manufacturer figures, and the palm publication gives rootball radii, in inches or feet, for a few named palm species only. No official page read for this guide gives one root ball rule that covers every tree.