Soil Ecology and Research Group last update August 24, 2001

Treeshelters Improve Woody Transplant Survival on Arid Lands (California)

Abstract

Researchers with the Desert Revegetation Group have determined that, when used correctly, treeshelters provide tree and shrub seedlings the means to survive the vagaries of an arid environment. Moreover, by placing these sections of translucent tubing over seedlings, restorationists can create a micro-environment that will shorten the time needed to revegetate a damaged arid site.

Restoration projects depend upon our ability to re-establish plants. This task is especially difficult in arid areas where direct seeding does poorly and where transplanted seedlings encounter a variety of stresses including damage from grazing, herbivory, drought, wind, sand, and extreme temperatures. Over the past five years, we have explored the potential of treeshelters to improve the establishment of variety of arid land trees and shrubs.

Several trials have shown us the benefits of treeshelters. The first experiment was a highway revegetation site near the Salton Sea, where we placed 24-inch TUBEX Treeshelters over mesquite (Prosopis glandulosa) seedlings. Treeshelters increased the long-term survival and growth of the seedlings when compared to similar plants placed in either white PVC tubing or open plastic mesh (Bainbridge, 1991). In another test using nearly 100 ocotillo (Fouquieria splendens), we found that tree-sheltered seedlings had a four times greater survival rate after one year. In July 1993, we planted a large number of cat claw acacia (Acacia greggii) seedlins on a barren overburden pile in the Mojave Desert. After two months, the plants in treeshelters had nearly twice as many leaves and were twice as tall as plants without treeshelters.

In 1992, NaDene Sorensen in the Ecology Program at San Diego State University conducted research on the physiological effects of treeshelters on creosote bush (Larrea divaricata). Her research included a detailed analysis of the environmental conditions inside treeshelters. She found that the interiors of treeshelters have lower light levels, higher temperatures, a shorter growing season, and less relative humidity than conditions might appear to discourage or slow plant development, the ability of a treeshelter to exclude the extremes of a desert environment apparently offset negative conditions for most species.

Solid tube treeshelters also make good recepracles for watering plants in the field. The tubes concentrate valuable water near the shrub, where it becomes more available to roots with less lost to evaporation. Restorationists will find this especially valuable when working on inaccessible, steep slopes.

Our studies indicate that treeshelters provide valuable protection for transplanted seedlings in an arid land restoration. Most plant species benefit from shirt-term (four to six weeks) use of treeshelters. However, summer-active species such as ocotillo, mesquite, bursage (Ambrosia dumosa), and four-wing saltbush (Artiplex canescens) with their upright forms, rapid growth rates, and ability to thrive under lower light levels may be particularly suitable for treeshelters.

Treeshelters are available from a number of outlets including TUBEX Treeshelter, 75 Bidwell Street, Suite 105, St. Paul, MN 55107, (800) 328-4827 ext. 1906; Treepee, Baileys, 44650 Hwy 101, Box 550, Laytonville, CA 95454, (707) 984-6133; Tree Pro Tree Protectors, 445 Lourdes Lane, Lafayette, IN 47905, (317) 463-1011; Tree Sentry, P.O. Box 607, Perrysburg, OH 43552, (419) 872-6950; and BLUE-X, All Season Wholesale Nursery, 10656 Sheldon Woods Way Elk Grove, CA 95624 (916) 689-0902.