Saving native trees

Developers in the Phoenix, Ariz., area don’t just go into a native landscape and bulldoze the plants anymore. There are regulations against it. There are also a few landscape companies that specialize in salvaging those plants and reusing them in the same or other projects.

Native tree salvage isn’t a job for the faint of heart or those lacking in horticultural skills, however. It’s a painstaking operation that, if done improperly, can lead to a lot of dead trees. One company in Phoenix, Native Resources International, established itself early on as a leader in this field and now has the system down pat. The company has saved thousands of native trees that now adorn the landscapes of Arizona.

Patty Cascio is the environmental team leader and marketing director at NRI, which is located on the far north side of town where it has enough acreage for its offices, a nursery for salvaged trees and demonstration plantings. The company has some 130 employees and did $11 million in sales in 2006. It’s also a company whose employees take their jobs to heart with a missionary zeal. They believe in the work they do, and the result is a high survival rate for trees.

Cascio says that co-owners Rob Kater and Jeff Homan had a landscaping business and a native seed collection business, respectively, in 1989 when the city of Scottsdale drafted an ordinance that required developers to salvage any native plants they removed from a site. Since that time, many cities in Arizona and the Southwest have adopted similar regulations, creating a lot of work for qualified companies.

“They set up a company to do plant salvage and revegetation services,” Cascio says, and the boom in land development in the region has given the company work as far away as California and Wyoming. The company also specializes in restoration of wetlands, which sometimes also involves plant salvage.

The steps to a successful salvage and revegetation project are:

1. Plant inventory is done using GPS and plants are catalogued.

2. NRI has a department that coordinates between the developer and the city to facilitate permits and adherence to regulations.

3. The plants are salvaged and established in nurseries, either on-site or at other locations.

4. Finally, site restoration and revegetation is undertaken, though sometimes the salvaged plants are not needed and can be sold or used in other landscaping projects.

A tree salvage operation can be a huge project when thousands of plants must be saved, but even a single, large, desert tree requires a lot of work and weeks of time to save successfully, Cascio says. They are dug out and boxed. The main trees the company saves are mesquite, two species of palo verde, ironwood and crucifixion thorn, but some large shrubs, like catclaw acacia and greythorn, can also be boxed.

Patty Cascio, environmental team leader for Native Resources International in Phoenix, says that boxing desert trees, such as these palo verdes, requires weeks of time to do properly.

“Generally, large ocotillos are boxed, and Yucca elata, if over 10 feet tall, they’re boxed as well,” Cascio says. Some cactuses may be boxed. Saguaros are not usually boxed, but exceptionally large specimens may be in order to better preserve roots.

Depending on each city’s ordinance, generally all trees 4 inches in diameter or larger and all cactuses 3 feet in height or taller must be tagged and salvaged. Smaller plants may also be tallied and saved if so desired. Trees designated as unsalvageable are those with bad structure, diseased roots or infestations of mistletoe. An NRI salvage crew usually consists of 10 people, but the company can put up to 60 people on a job if the site demands it or there is an impending deadline. Required equipment consists of backhoes, front-end loaders, flatbed trucks, semi trailers and water trucks.

Boxing trees in situ is an established process, but NRI crews have become very good at it, so good that they guarantee 90 percent survival for one year, and usually get over 95 percent survival if the salvage is done in the warm weather between March 15 and October 15. This seems counterintuitive, since hot weather is usually not a good time for moving plants, but Cascio says that desert trees and shrubs are best removed in the growing season. The exception is the creosote bush, which survives better with a winter salvage.

The first job is to prune the tree’s canopy back, though less than 25 percent, to remove dead wood, misshapen branches and any wood that will interfere with digging operations. “You want to leave the natural shape of the tree,” Cascio says, but unwieldy trees or those with multiple trunks can pose a problem. Crews plan to remove about the same percentage of canopy as they will remove of the roots, which insures the health of the tree once replanted.

Then the crew will hand-dig to establish dig trenches. These are carefully planned to match the size of the box the tree will require. Boxes range in size from 36 inches for a 4-inch diameter tree up to 72 inches for a 15-inch tree, as measured 1 foot up the trunk. From there, larger boxes may be used for huge trees. The largest box NRI has used was 120 inches. The company builds its own boxing materials at its Phoenix offices.

Trenches are dug by hand down through the rootzone on all four sides of the tree, with roots carefully sawed off as they go. The company’s experienced crews leave the amount of roots they think will allow the tree to survive. Ready-made box sides are used to assemble the box around the tree’s roots, and braces are fastened across the top to keep it stable. The bottom is left off for the time being, and the tree is watered and allowed to sit and adjust for at least three weeks.

Tree roots are encased in boxes from 36 inches to 120 inches wide, and the company uses so many that it manufactures them itself.

NRI’s supervisors are not only experienced, they have degrees in fields such as botany and environmental resources. Cascio herself has a degree in natural environmental resources and has worked for the company almost from the start. Although arborists are only brought in as consultants if needed, many of the company’s workers and supervisors have gotten training from the Desert Botanical Garden in the salvage and care of native species.

“After three weeks, you excavate to one side of the box farther out,” Cascio says, and the tree is gradually tipped to the opposite side as the bottom is excavated. The bottom is boxed as it is revealed, and the box banded for strength. Then the tree will sit for another week, if possible, before removal. Loaders are used to remove small trees, and a crane is used for large trees that take boxes in the 108 to 120-inch range.

It can take a crew of 10 a couple of days to excavate a large tree and box it, at a cost of around $3,500. “Our bids are pretty much based on the caliper of the tree,” Cascio points out, and there is little cost cutting. In fact, most cities require that a company have its methodologies certified before it will approve a contract.

Trees are flagged on the north side so they can be replanted with the same orientation. Once the tree is removed to a nursery situation, it is put on a drip irrigation system so that it can be watered efficiently. When it is replanted, it is placed in a hole that is half again bigger than the box and dug to the exact depth of the box. Banding is cut, and the sides are removed gradually as backfill is added to the hole. Ideally, the crew waters the tree for a week so the roots cling to the soil. The bottom is left on and will deteriorate with time.

Trees with a deeper root system—those growing in sandy soils, for example—require a deeper box, but most of these desert trees don’t have taproots. The catclaw acacias do have a taproot, and those have a lower survival rate and are moved less often.

“On salvaged trees you need to water them for about two and a half years,” Cascio says. Thus, irrigation methods must be planned, since some developments don’t get their permanent irrigation systems right away. If irrigation is tapered off gradually, the trees will eventually be able to survive on their own under natural rainfall.

Many of the trees and other plants salvaged go back into the housing development or golf course sites they were removed from, but NRI also has a landscaping department that installs urban landscapes using some of these transplants. It also has an active trail-building operation that uses salvaged plant materials where possible. Other trees may be sold to other landscape companies—NRI has a wholesale nursery business for that purpose.

The company’s separate wetland and riparian restoration department may also salvage some trees, but that is unusual. Usually, those plantings are of trees like willows that are grown from cuttings of native species. That has been done from Washington state to Mexico. NRI has a sister company in Henderson, Nev., Native Resources of Nevada, that specializes in salvage and revegetation in the active Las Vegas market. A final aspect of this work once planting is finished is to GPS trees and as-builts, such as irrigation valve boxes.

Native Resources International has landscaped its offices in north Phoenix solely with salvaged desert trees and shrubs.

Obviously, with the company working in states such as Wyoming and Washington, NRI doesn’t limit itself to desert salvage. NRI has successfully transplanted species such as pinyon pine, manzanita and ponderosa pine. The company has done work as varied as wetland mitigation planning and mining reclamation projects. It is expert at using salt-tolerant plants to create landscapes in saline environments, and has a division that does environmental consulting on an international basis. It also has a division in Hermosillo, Mexico, that works on large, commercial projects.

NRI generally sticks to commercial projects, with a lot of experience in golf courses and shopping complexes in the desert. The company promotes its image as an environmentally sensitive landscaper. It will also utilize its expertise to landscape select, high-end, custom homes. To see the scope of NRI’s projects, visit

In keeping with the environmental goals of the company, NRI has planted its 5-acre office complex solely with salvaged trees and shrubs. The company has not only created a beautiful landscape, it has also planted a section of demonstration plants where school groups are invited to learn about native vegetation and wildlife. A storyteller will talk to the kids about the environment, and each student will be given a mesquite seed to plant and a two-year-old saguaro to take home.

Don Dale is a freelance writer and a frequent contributor. He resides in Altadena, Calif.