8/10/2011. Lesson Overview. Rangelands. Rangelands. Brush management on rangelands. Advantages and disadvantages. Specific mechanical treatments

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1 Lesson Overview Brush management on rangelands Advantages and disadvantages Specific mechanical treatments Brush dominates areas across TX that were previously dominated by grasses. Coping with dense brush can be costly and often futile. Eradication is impossible. Brush management became popular & reflected the notion that some woody species are valuable. Particularly to wildlife which became increasingly more valuable to ranchers. 1

2 Brush management may improve or degrade habitat depending on: Wildlife species Type of treatment When treatment applied Weather, soil, plant community, etc. Advantages: Precise treatment area while leaving untreated areas Soil disturbance Seedbed prep Increase forb production GPS/GIS to achieve mosaic Re-growth of browse greater in nutrition, palatability Increase water yield Disadvantages Costs Stimulates undesirable forbs and browse Invasion of exotics Increased shrub stem and plant densities Increased thorns Temporary effects 2

3 Land managers must be able to see into the future from initial treatment and plan follow up practices to achieve desired results. Before After Types of Brush Management Selective thinning - Plant removal from below ground. Selective clearing - Top growth removal from ground up. 3

4 Grubbing By hand, pick, grubbing hoe, or U-shape blade Highly selectiveec e High kill rate 155 mesquite/hour Cost prohibitive for large stands Creates pits Debris left over Root Plow Blade below soil Effective at killing brush Increase in grass and forbs Costly (Raking, reseed) Can destroy other veg. Can decrease species diversity Bulldozing Removes veg. at or below soil surface May cause considerable soil disturbance Moderately selective Best for use on large non-sprouting species in scattered stands 4

5 Trackhoe Used to excavate trees or brush plants Knock down trees Pile debris Create pits/tanks 5

6 Aerator Reduce soil compaction and increase water infiltration Suppresses brush while leaving herbaceous veg intact Re-sprouting Roller Chopping Crush & sever stems Increase in shrub sprouts Maintenance every 2-5 years Mowing Maintenance treatment Increases palatability of shrubs Area must be free of large debris, stumps, etc. 6

7 Base Shearing Selective Not recommended for sprouting brush species Used for cedar removal in Hill Country 7

8 Disking Effective on small, shallow-rooted species Not effective in rocky soils Strip-disking effective for emerging vegetation Ready for reseeding 8

9 Chaining Heavy chain pulled between 2 crawlers Effective on thin to moderate stands of brush Plant kill is low and re-growth is rapid Debris 9

10 Mulching Mulches trees and brush Coarse mulch left behind Selective No debris piles or burning Cost 10

11 Raking Collect and pile debris post treatment Used to remove prickly pear 11

12 Managing Landscapes for Wildlife Wildlife species vary in requirements for Patch size Woody plant cover and density Plant species diversity Woodland versus grassland species Interior versus edge species Scale of Application - Effects of brush management on wildlife may vary dramatically depending on scale of application - Many grassland-adapted species may show a positive response to large scale conversion of woodland to grassland - Landscape composition may interact with patch size - Larger core areas may be more important in landscapes with a mixture of grassland and woodland than in treeless landscapes Bobwhites used patches that averaged >30% woody cover Grass and forb cover did not influence habitat selection Prefer 20-60% woody canopy cover Brush management not likely to benefit bobwhites unless canopy cover >60% 12

13 Brush management may result in long-term changes that are undesirable Only way to improve habitats degraded by brush management is often more brush management 13