Woody Encroachment Archives - Page 2 of 4

Ten Years of Mesquite Application Timing…Spray a Healthy Tree or Wait Until 75F Soil Temperature?

October 15, 2025 by jaime.sanford

Mesquite (Prosopis spp.) is a tough, invasive shrub that plagues rangelands across Texas and beyond, outcompeting native grasses, reducing forage for livestock, and altering wildlife habitats. For ranchers aiming to boost grazing productivity, conservationists focused on restoring biodiversity, and wildlife managers enhancing quail or deer cover, effective mesquite management is key. But timing your herbicide applications, especially foliar sprays, can make all the difference. Drawing from a ten-year dataset spanning counties like Hamilton, Jack, Hood, Eastland, Comanche, Tom Green, and Schleicher, let’s explore how environmental factors like soil temperature influence mesquite mortality rates one and two years after treatment (YAT).

Insights from the Field Trials

This dataset compiled over 500 observations across 10 years from individual plant treatment (IPT), from 5 Texas counties, tracking percent mortality alongside variables such as soil temperature (12-inch depth), air temperature, and relative humidity. While individual results varied by site and conditions, clear patterns emerge when we aggregate the data.

Peak Performance in Late Spring/Early Summer: Applications in May and June yielded the highest average mortality—around 88% at 1 YAT and 92% at 2 YAT in May, dropping slightly to 85% and 86% in June. These months coincide with rising soil temperatures (averaging 70°F in May and 79°F in June), when mesquite is actively growing and translocating herbicides to roots more effectively.
Decline in Late Summer and Fall: By July and August, averages dip to 75% (1 YAT) and 66% (2 YAT) in July, further to 56% and 68% in August, despite warmer soils (82°F average). September through November show even lower efficacy, with November applications averaging just 3% at 1 YAT and 9% at 2 YAT—likely due to cooler soils (68°F) and plants entering dormancy.
Soil Temperature’s Role: While warmer soils are indicative of growing conditions, it is not the primary driver of plant mortality – IT’S THE TREE!!! There is no statistical significant difference between spraying below 75F and above 75F (P = 0.300) soil temperature at 12” depth. These results emphasize that if the target tree is healthy, full leaf, and mature in phenology stage, it is ready to be sprayed!

Practical Tips for Your Operation

Target May-June Window: For most Texas regions, this period offers the sweet spot of active growth without excessive heat stress, grasshoppers or other insect damage, and hopefully before cotton is in the ground. Adjust for your county’s microclimate, e.g., earlier in southern areas like Tom Green.

By syncing sprays with healthy trees and peak growth, you can achieve higher kill rates, saving time and resources while promoting healthier rangelands. Whether you’re running cattle, promoting biodiversity, or managing for open-spaces, data-driven timing turns mesquite from foe to forgotten!! Happy spraying and spray for the tree!

*These data are currently being drafted for submission to Rangeland Ecology and Management.

Structural Changes Drive Functional Changes

February 26, 2025 by jaime.sanford

Rangelands, vast and vital, are more than just scenic landscapes. They’re complex ecosystems providing essential services, from clean air and water to livestock grazing and wildlife habitat. But these valuable areas face a growing threat: woody plant encroachment. This occurs when shrubs and trees increase in density and coverage, often at the expense of grasslands. While it might seem like a simple change in vegetation, the consequences are far-reaching, impacting everything from soil health to water availability.

Non-Target Woody Plant Response to Herbicides

January 29, 2025 by jaime.sanford

Ranchers in West Texas frequently encounter a double-decker challenge with intense canopy coverage from honey mesquite and dense pricklypear in the understory. Synergistic broadcast herbicide applications are commonly employed to tackle these layered problematic, opportunistic, and abundant species. However, it is crucial to recognize the potential for unintended consequences on nontarget woody plant species. A recent study delved into the effects of various herbicide treatments on both target and nontarget woody plant species.

Portugal Wildfires and What Does That Have to do With Texas?

November 6, 2024 by jaime.sanford

The Euro-Mediterranean region is a high fire prone area with 48,000 fires reported annually. The fires are the result of landscape fuel build up which has been driven by absentee land ownership, wildfire suppression policies, extreme temperatures, and extended droughts that simultaneously occur. This study used the LANDIS-II forest landscape model which is considered a fire-smart management tool. Fire-smart management is based on controlling fire regimes through landscape interventions to reduce hazardous fuels and foster fire-resistant/resilient landscapes. The study included assessing how alternative fire management strategies affect future landscape dynamics, the fire regulation capacity, and fire regimes under long-term absentee land ownership and extreme climate scenarios.

Woody Plant Encroachment – What other states are doing and saying

September 25, 2024 by jaime.sanford

Extreme climate swings, lengthened fire seasons, drought, floods, overgrazing, fragmentation, land-use change, urbanization, and altered disturbance regimes has created an increase in woody plants, commonly referred to as woody plant encroachment or (WPE). Woody encroachment has become a global phenomenon in nearly all grassland ecosystems. We have seen the devastating results of WPE in Texas grasslands and savannas and as we learn from our North Central partners (CO, KS, MT, ND, NE, SD, and WY) many of these states are on a similar trajectory of plant community transition. Through the work of the North Central Climate Adaptation Science Center and the Rangeland Analysis Platform, other states can learn from our Texas lessons of WPE and aim for fire return intervals that minimize initial spread of woody species in grasslands.

Stability of C3 and C4 Grass Patches in Woody Encroached Rangeland after Fire and Simulated Grazing

August 28, 2024 by jaime.sanford

In the western portion of the southern Great Plains, grasslands are defined as “southern mixed”, with warm season or C4 mid-grasses being dominant and cool season or C3 short-grasses in less frequent densities. As woody plant encroachment increasingly dominates, the productive warm season C4 grasses begin to decline with less abundance on the landscape and even less productivity. Woody plant dominance also reduces plant diversity eroding heterogeneity in the mixed-grass prairie. Recently, researchers measured the effects of various combinations of spring clipping (mimicked cattle grazing) and prescribed fire treatments over an 8 year period on Texas wintergrass and buffalograss with the overall objective of reducing Texas wintergrass abundance and increasing warm season C4 mid-grass species and diversity.

Impact of Goats on Cattle Diet Composition

August 14, 2024 by jaime.sanford

Did you know that having goats in your pasture could potentially complement the existing cattle operation while boosting livestock productivity and plant community diversity? Goats normally prefer and preferentially consume various types of woody and forb species more so than cattle do, and that their presence in a pasture does not alter what the cattle preferentially select to eat.

Influence of Environment and Stage of Growth on Honey Mesquite Response to Herbicides

August 7, 2024 by jaime.sanford

Honey mesquite varies widely in its response to herbicides. Previous research demonstrates most effective treatments have occurred about 50 to 90 days after the first leaves appear in the spring when they are fully formed and dark green (Bovey and Mayeux, Jr. 1981; Jacoby and Meyers 1983; Meyer et al., 1986). More recently, triclopyr has been found to be effective for control of honey mesquite (Bovey and Mayeux, Jr. 1981; Jacoby et al., 1981; Jacoby and Meadors 1983). Also, clopyralid has been found to be highly effective for controlling honey mesquite (Bovey and Mayeux, Jr. 1981; Jacoby et al., 1981).

CO2 Flux over Burned Honey Mesquite Savanna Rangeland

April 24, 2024 by jaime.sanford

Prescribed fire is a management practice used to reduce woody plant encroachment on rangeland and maintain native perennial grass diversity and productivity. Prescribed fire effects on CO2 fluxes and their contribution to atmospheric CO2 is not well known. The study below discusses the effect of fire on net ecosystem CO2 flux above Prosopis glandulosa Torr. (honey mesquite) using the Bowen ratio/energy balance method (BREB), and to compare these fluxes to fluxes determined by an empirical model.

Extreme Prescribed Fire during Drought Reduces Survival and Density of Woody Resprouters

April 3, 2024 by jaime.sanford

Researchers looked at extreme fire conditions during drought in humid subtropical and semi-arid ecoregions that require innovative management strategies that go beyond the traditional restoration and conservation practices. These practices have either been historically ineffective or economically cost-prohibitive at restoring grass-dominated ecosystems following conversion to resprouting shrublands.