Juniper Management and Control in Texas
Junipers, or cedars as they are commonly known, are a major management concern throughout much of central Texas. Over the last century, the land use and management across the Edwards Plateau region has seen a dramatic increase in the juniper (Juniperus Ashei) population. The results have been extremely negative. For instance, the native hardwood trees have been overgrown by the juniper resulting in a less productive rangeland and impacting the water table in this region. Therefore, juniper management must be approached from a multi-standpoint: rangeland management, watershed management, wildlife management and human wellness.
The consequences of juniper overgrowth are costly for both rancher and city dweller. The ranchers are continually faced with the expensive proposition of juniper elimination. Since this tree is of little to no value to livestock, it must be manually removed from rangeland or junipers will overcome the rangeland. The juniper is a tremendous water user. It not only consumes the groundwater in the area of its canopy, it also restricts rainfall from ever reaching the ground and subsequently the reservoirs. Therefore, junipers limit grass production by intercepting rainfall before it reaches the ground and thereby restricting the water, nutrients and sunlight necessary for a diverse plant population. As a further detriment to more beneficial plant species, junipers have an extensive lateral and deep root structure, which enables a juniper to extract water from dry soil very effectively. Junipers also generate a heavy litter under their canopy. This leads to a reduction of plant species under junipers. Since junipers do not tend to be grazed, they grow and then out-compete other plants for water, sunlight and nutrients. The juniper must be targeted as a very bad plant.
From a city dweller standpoint, the juniper reduces available water as stated and it is a major source of human allergies in the winter when it pollinates. Both of these are important issues and need the attention of government land and water management agencies as well as individuals. It is likely the individual can have the greatest impact on managing down the juniper populations. Every homeowner should remove juniper seedlings as a first step to control.
How to better manage junipers
Since junipers are more of a hindrance to good land management, the goal should be to eliminate these pesky trees and continue to follow up until they are eradicated. Once large junipers are removed, the water, sunlight and nutrients are available to the diverse native plants. Since juniper seedlings are quick to get established, the seedlings must be removed in a follow-up removal before implementing control treatments. This is important since junipers are more vulnerable as seedlings/saplings.
Examples of Juniper Management at Selah Ranch
Mechanical methods for removal of junipers can be done by: grubbing, bulldozing, root plowing, or using chains. Since large areas are typically involved, the best method may be predicated on cost. Ashe junipers are particularly well managed using hydraulic shears since the ashe juniper doesn’t resprout. Whatever the method, there must be follow-up treatment about every 7 years since juniper seed production is so prolific.
In Texas, there's a project underway to bring back the grasslands though, and it starts with the removal of more than 400,000 acres of juniper and mesquite. The 1999 Texas Legislature approved $7 million for the North Concho Brush Management Plan. An additional $1 million was appropriated for feasibility studies for the Canadian River, Wichita River, Upper Colorado River, Middle Concho River, Nueces River, Frio River, Pedernales River and Edwards Aquifer. The North Concho is the only river where actual brush removal was funded.
The brush removal is done by both mechanical and chemical means. Most landowners use a bulldozer with a grubber, a piece of machinery that pulls plants out of the ground. Tree shears can also be used, but stumps must be sprayed with herbicides to kill the root system, since both types of brush will re-sprout. Mesquite can be treated by air as well.
Chemical Management Approach
Using chemicals to control juniper is best done to seedling/sapling plants. Current chemicals that prove effective are: Velpar L at ground level and 1% Tordon 22K leaf spray. Velpar is nonspecific and therefore will affect other plants so it must be handled with caution. There is no effective broadcast herbicide available as yet.
Fire Management Methods
A very effective of juniper control is prescribed burning. This method is great for early juniper stands since fire is not tolerated by young (< 4 feet tall) juniper. One approach is to let native grasses get the upper hand by initially roller chopping the area of junipers. This retards the junipers while the grasses take hold. Once the grasses are mature they become good kindling for a controlled burn. Plan to repeat this in a few years to insure complete juniper elimination. After successful burns, range grasses should be replaced through seeding to avoid erosion.
One of the most widely used biological approach methods to control juniper is to introduce goats to the area for grazing. Goats tolerate the volatile oils inherent to juniper and they are particularly effective against new juniper seedlings/saplings. Since goats do not favor juniper over other forage, the use of goats is more effective in the winter when other forage is dormant.
A second biological approach is to encourage the juniper budworm. The juniper budworm attacks by larvae feeding on the juniper foliage, they construct silken tubes and pupation occurs in the shelter where the larvae fed. It is not known exactly what impact the juniper webworm will have on the Ashe juniper in Central Texas. So, landowners should encourage the budworm by avoiding pesticides on juniper stands. It is not clear what affect other control methods may have on juniper budworms.
Juniper Budworm Samples
Juniper budworm research could lead to an effective juniper control methodology. Any interested parties, who have skill in this area of plant pathology, are encouraged to contact PAC to discuss research potential.