Pinyon Pine and Juniper Tree Invasion into New Mexico’s Grasslands:

1. Pinyon Pine and Juniper Tree Invasion into New Mexico’s Grasslands: Some Hydro-Ecological Considerations Dr. M. Karl Wood, Director Water Resources Research Institute New Mexico State University

2. The Nature of New Mexico’s Watersheds

4. # 1Environmental Problem in New Mexico? Tree and Shrub Increase and Invasion! Such as: Salt Cedar, Russian Olive, Mesquite, Creosotebush, and especially Pinyon Pines and Junipers

5. 1900

6. 1960

8. Landscapes Containing Pinyon Pines and Junipers Seed dispersal by gravity, water, wind, animals, etc Rocky and sparse vegetation, incapable of carrying a fire Low lands Steep Hillsides Mesa Tops Physiographic Positions

12. Roots from Pinyon Pines and Junipers Extend about 2.5 times the radius of the crown, in all directions, and just beneath surface of soil

19. Erosion After Dominance Amount of Erosion Grassland Pinyon-Juniper Pinyon-JuniperDominated Invasion Established

20. Erosion After Dominance Amount of Erosion Grassland Pinyon-Juniper Pinyon-JuniperDominated Invasion Established

24. Diversity (number of plant & animal species) Bare Early Intermediate Late Climax Rock Seral Stage

25. Pinyon pine and Juniper • Climax on steep, rocky hillsides • Invade lowlands & mesa tops by gravity, water, wind, animals, etc • Controlled by fire in invaded areas until fire became scarce • Compete with grass-forb-shrub understory which results in extremely high erosion rates

26. Kinds of Mismanagement! • Cessation of wildfire by fire suppression • Limiting use of shrub and tree control tools such as: a. Fuelwood harvest b. Mechanical removal c. Herbicide applications

27. Kinds of Mismanagement! • Overgrazing?

28. Solutions! • The Clean Water Act amendments of 1972 require the application of BestManagement Practices to control non-point source pollution • Best Management Practices were determined for all New Mexico lands by the State of New Mexico and approved by the U.S. Environmental Protection Agency in the early 1980’s • Allowing pinyon pines and junipers to invade grasslands is a gross violation of the Clean Water Act

29. Study: Reclaiming Grassland Invaded by Pinyin Pines and Junipers • Location: Gila N.F. near Cooney Prairie • When: 1986-1999 • Treatments: • Untreated control plots 2. Clearcut with slash removed • Clearcut with slash scattered 4. Clearcut with slash scattered and burned 4 months later 5. Clearcut with slash scattered and burned 27 months later

33. How much water can be squeezed from Pinyon pine - Juniper invaded areas? • About 8.75 million acres of pinyon pine and juniper woodland in New Mexico • If water yield could be increased by 1 inch: The volume would be 725,000 acre-ft or about a year’s supply of irrigation and municipal water from Elephant Butte Reservoir

36. Conclusions Scatter slash Best No resprout potential Scatter slash & Best Resprout delayed burn potential Remove slash Good Some risk first 2 years Scatter slash & Fair immediate burn No harvesting Worst

37. Risks from complete tree removalcan be lessoned by: • Seeding • Pitting • Contour Furrowing and Terracing • Ripping • Shaping and grading • Top soiling • Cultivation • Surface mulching • Chisling, offset-listering, gouging, waffling, basin forming • Fertilization • And probably many others

38. Conclusions • Pinyon pines and junipers invade grasslands resulting in: • loss of plant and animal diversity • loss of plant and animal production • changed timing of runoff • accelerated erosion • Removing pinyon pines and junipers from former grasslands represents a Clean Water Act “Best Management Practice”

39. A Good Quote “If the prime objective is wood products, we may continue to overgraze, letting in the woodland and sacrificing watershed values If on the other hand the prime objective is watersheds, we should restore the grass, which all the evidence indicates is a better watershed cover than either brush or woodland” Aldo Leopold