Pinyon Pine and Juniper Tree Invasion into New Mexico’s Grasslands:
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Pinyon Pine and Juniper Tree Invasion into New Mexico’s Grasslands: Dr. M. Karl Wood, Director Water Resources Research Institute New Mexico State University Some Hydro-Ecological Considerations
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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. The Nature of New Mexico’s Watersheds. # 1 Environmental Problem in New Mexico?. - PowerPoint PPT Presentation
Transcript of Pinyon Pine and Juniper Tree Invasion into New Mexico’s Grasslands:
Pinyon Pine and Juniper Tree Invasion into New Mexico’s
Grasslands:
Dr. M. Karl Wood, Director
Water Resources Research Institute
New Mexico State University
Some Hydro-Ecological Considerations
The Nature of New Mexico’s Watersheds
# 1Environmental Problem
in New Mexico?Tree and Shrub Increase and Invasion!
Such as: Salt Cedar, Russian Olive, Mesquite,Creosotebush,
andespecially Pinyon Pines and Junipers
1900
1960
Landscapes Containing Pinyon Pines and Junipers
Low lands Steep Hillsides Mesa Tops
Physiographic Positions
Seed dispersal by gravity, water, wind, animals, etc
Rocky and sparse vegetation,
incapable of carrying a fire
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
Erosion After Dominance
Grassland Pinyon-Juniper Pinyon-Juniper Dominated Invasion Established
Amount of Erosion
Erosion After Dominance
Grassland Pinyon-Juniper Pinyon-Juniper Dominated Invasion Established
Amount of Erosion
Diversity(number of plant
& animalspecies)
Bare Early Intermediate Late Climax Rock
Seral Stage
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
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
Kinds of Mismanagement!
• Overgrazing?
Solutions!
• The Clean Water Act amendments of 1972 require the application of Best Management 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
Study: Reclaiming Grassland Invaded by Pinyin Pines and Junipers
• Location: Gila N.F. near Cooney Prairie• When: 1986-1999• Treatments:
1. Untreated control plots
2. Clearcut with slash removed
3. Clearcut with slash scattered
4. Clearcut with slash scattered and burned 4 months later
5. Clearcut with slash scattered and burned 27 months later
Total Yearly Grass and Forb Production
0500
100015002000250030003500
'88 '89 '90 '91 '92 '93 '94 '95 '96 '97 '98 '99
Years
Mas
s (kg
/ha)
Control Remove Scatter Burn '89 Burn '91
Mean Annual Runoff
0
20
40
60
80
100
'88 '89 '90 '91 '92 '93 '94 '95 '96 '97 '98 '99
Years
Dep
th (m
m)
Control Remove Scatter Burn '89 Burn '91
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
Mean Sediment Concentration
0
2
4
6
8
10
'88 '89 '90 '91 '92 '93 '94 '95 '96 '97 '98 '99
Years
Mas
s (k
g/cu
bic
met
er)
Control Remove Scatter Burn '89 Burn '91
Mean Annual Bedload
0
200
400
600
800
1000
1200
'88 '89 '90 '91 '92 '93 '94 '95 '96 '97 '98 '99
Years
Mas
s (k
g/ha
)
Control Remove Scatter Burn '89 Burn '91
Conclusions
Scatter slash Best No resprout potential
Scatter slash & Best Resprout delayed burn potential
Remove slash Good Some risk first 2 years
Scatter slash & Fairimmediate burn
No harvesting Worst
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
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”
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
