Rangeland Assessment and Recovery Following the Heartstrong Wildfire
March 26th Update
The precipitation received on March 22nd has helped surviving plants to initiate new growth within the area of the Heartstrong Wildfire. In many areas of the fire, grasses are growing again. This is encouraging, since there is evidence that many plant crowns did survive the fire. Below are some photos taken on March 26th (Figures A-D). Even though many of the grasses are responding to the fire, much of the yucca and sand sagebrush suffered high mortality. Areas of CRP also do not appear to be responding as well to the fire, with much of the taller grasses found on CRP land suffering high plant mortality. Use of equipment and vehicles should be avoided on the native rangeland as much as possible. Spring winds can cause new soil erosion hotspots to occur in areas where equipment/vehicles are used. Where blowouts have been exacerbated or have been newly created, active management strategies should be used to minimize the movement of sand and soil. However, treatments should only be done if problem areas can be accessed without causing more damage to the soil. See the text below in the March 22nd posting for more information on this topic.
Figure A. A bunchgrass initiating new growth (lower left corner of plant, 3/26/2012).
Figure B. New grass growth, one week post-fire (3/26/2012).
Figure C. Leaves emerging from the sand (3/26/2012).
Figure D. In this photo you can see the apparent light green from new grass growth, even though many of the sand sagebrush and yucca suffered heavy mortality (3/26/2012).
If you were affected by the Heartstrong Wildfire and are seeking aid, please contact your local your local Extension, Conservation District, and/or NRCS office.
March 23rd Post
Precipitation, approximately one third of an inch, was received on March 22nd in the area of the Heartstrong Fire. This rainfall will help decrease the mobility of soil particles to wind erosion, as well as give recovering plants a boost of moisture.
March 22nd Post - Heartstrong Rangeland Fire Initial Assessment
The recent March fires in Yuma and Phillips county have reminded us how much impact wind and fire can have on the range. In the wake of the destruction, landowners are eager to do something, anything, to improve things. The first thing that should be done prior to taking any action is to assess current conditions. The ability of the range to recover following the fire is primarily influenced by the amount and quality of plant parts that survived the fire. These may include seeds, roots, crowns, shoots, and stems. Secondary factors that influence soil stability and growing conditions for plants following the fire include: 1) time of year (time left in the growing season), 2) current soil moisture, 3) amount of plant litter on soil surface, 4) post-fire precipitation and temperatures, 5) wind, and 6) management actions.
The pre-fire standing vegetation for the native and seeded rangelands within the boundary of the wildfire has been estimated to range from approximately 300 lbs/acre to 1,200 lbs/acre. Sections that were more heavily utilized by grazing had lower pounds per acre of standing vegetation or had lesser amounts of yucca and sand sagebrush. Areas of CRP were estimated at greater than 1,200 lbs/acre of standing vegetation. Areas with greater vegetation (taller and denser plant material) had higher fuel loads for the fire and were subject to burning hotter and longer than areas with shorter and sparser vegetation. An inventory of plant and soil conditions after the fire on March 20th and 21st revealed that many perennial grass crowns and roots appeared to have survived the fire. Depending on location, wind movement had caused erosion around plants, exposing their roots (Figures 1 and 2). Plants suffering erosion around their roots will eventually desiccate and die. Other plants showed evidence of deposition of soil materials (catching soil) and being covered with fine sand (Figure 3). Plants covered with soil, as long as the soil depth is not too deep, are likely to regrow this spring. Some plant crowns that did not show evidence of being eroded and appeared intact may still suffer mortality due to lethal temperatures experienced during the fire. Additionally, examination of the soil profile showed that ample soil moisture for plant growth was evident starting at a depth of only two inches from the soil surface. It is difficult to assess whether or not any viable seed survived the wildfire, due to the amount of windblown material experienced during the fire and post-fire in addition to high temperatures experienced during the fire. Areas of CRP and native rangeland with dense yucca/sagebrush intermixed with grass experienced the greatest impact from fire. In these locations, fire extended down into plant crowns, killing plants. These areas have the greatest erosion potential with some locations showing some signs of blowouts beginning to occur, for example the soil erosion observed in Figure 1.
Figure 1. Photo showing wind erosion of approximately 3 inches of sandy soil around annual plant roots, due to high winds following the Heartstrong Fire.
Figure 2. Wind erosion of soil evident on one side of perennial grass roots (1 to 2 inches of sandy soil lost) following the Heartstrong Fire.
Figure 3. Remains of a prickly pear cactus catching windblown soil sediments following the Heartstrong Fire.
In areas where plant crowns are intact (Figures 4 and 5), active management should be avoided in order to reduce the risk of causing damage to intact plants or causing increases in wind erosion. In other areas that are easily accessible and show evidence of blowouts forming (areas where plant crowns are no longer intact) they should be treated (mulched) with old hay or cornstalks, straw, manure, or other organic materials such as tree limbs or other wood that will decompose over time. Best materials will be free of weed seed. Orienting the materials so that they will not blow away and so that they will block winds coming from the most prevalent directions will increase their efficiency at holding soil and catching sediments. Using degradable materials for these treatments adds to the potential to build soil and start the process of revegetation. Seeding prior to adding mulch with warm season species of plants up until about mid-May may yield success. In addition, in some cases, crimping the mulch into soil over the seeds may increase seedling establishment. Drilling warm season species of plants may also be effective, as long as soil disturbance and wind erosion potential is low. Every rangeland situation is unique, especially due to differences in topography and severity of fire, so before executing an active management strategy such as seeding or mulching it would be advisable to contact your local Extension, Conservation District, and/or NRCS office to develop a custom plan to increase your odds of success.
Figure 4. Intact crowns of perennial plants that survived the Heartstrong Fire.
Figure 5. Sand sagebrush, yucca, and native grass rangeland. Grass crowns are intact, but yucca and sand sagebrush suffered some mortality in this part of the Heartstrong Fire.