Native Plant Salvaging and Reuse in Southwestern Deserts - Design with the Desert: Conservation and Sustainable Development - page 403

the moisture content remains within an acceptable range until the next watering and a
soil probe is helpful for this task. Weather patterns, even short-term spikes in temperature,
wind velocity and humidity, are critical variables in the success of salvage tree survival.
23.2.3 Tree Spading
If a large tree spade is used for transplanting, much of the manual labor needed has been
eliminated. Generally, the spade captures over 90% of the root ball. The trees are then imme-
diately transported to the new site for transplanting. However, in many cases, tree boxing
is required due to the need to retain plants until a new site is ready for salvaged species.
23.2.4 Other Factors Affecting Tree Salvaging Success
Site assessments to determine the box size to be placed on each tree are a major component
of the tree salvage process. General guidelines are based on trunk caliper for each species.
However, soil type and drainage patterns also come into play. A larger box size captures
more feeder roots but presents greater handling problems. In the end, the ideal box size is
the smallest which will support a healthy transplant. Boxes are sized in 6 in. increments
in conformance with nursery industry standards. Typical tree boxes range from 36 to 72
in. Shrubs like creosote ( Larrea tridentata ) and jojoba ( Simmondsia chinensis ) are typically
salvaged in 24-48 in. boxes.
A related issue is the use of machines versus manual digging. The best argument for the
manual method is the original premise that less disturbance to the feeder roots typically
increases the success rate. Excavation by hand enables workers to carefully expose and cut
roots without shaking the root ball. Most salvage operators use a backhoe to dig trenches
around the tree. The problem with this method is the digging bucket tends to tear roots
rather than making a clean cut. With larger roots, the action of the teeth catching the
roots can cause significant disturbance to the root ball. However, if the root zone is hand
excavated, machinery may be used to complete the digging process as long as the roots are
not touched by the machine. A qualified operator is essential for this method. On average,
salvage companies have found that a given tree can be successfully salvaged using one
size smaller box with the manual digging method. For larger sizes (greater than a 48 in.
box), a combination of machine and manual digging can be very effective. A backhoe is
used to remove the larger quantities of soil near the surface but the manual method is used
in the zone where most of the roots occur.
The intent of the foregoing is to give the reader some appreciation of the intricacies
and practical issues related to saving native trees and cacti on a scale that can positively
impact the environment of our metropolitan areas. It is not intended to be a step by step
“how to” manual. The current results reported barely scratched the surface of all the
considerations relevant to successfully salvaging naturally occurring desert species. In
addition to dealing with climatic conditions, the salvage industry will most likely contend
with several levels of regulatory constraint and the driving forces of economic expansion.
Each of these factors provides both opportunities and challenges.
23.3 Challenges
Some laws and the regulatory agencies responsible for protecting native species may seem
at odds with the goal of saving native plants from destruction and maximizing their use in