8807049 THE CONDITION AND TREND OF ASPEN ON BLM LANDS NORTH-CENTRAL NEVADA IN - - WITH RECOMMENDATIONS FOR MANAGEMENT YEAR THREE Final report to Elko Field Office Bureau of Land Management 3900 Idaho Street Elko, NV 89801 by Charles E. Kay, Ph.D. Wildlife Ecology Wildlife Management Services 480 East 125 North Providence, UT 84332 753-0715 (435) May 2003 SD 397 A7 . K394 2003 c 2 . i%33 ACKNOWLEDGEMENTS This research was funded by the Bureau of Land Management (BLM) under Contract Number FBP 020036 and thank the agency for its support. BLM specialists I Skip Ritter, District Forester, and Ken Wilkinson, Wildlife Biologist, were extremely helpful in selecting study sites and providing documents germane to this study. This report is part of a continuing 5 year aspen study (2000-2004) between the Battle Mountain and Elko BLM Districts funded through the 5900 Forest Health and Restoration Program. Joe Ratliff, Project Coordinator with the Battle Mountain Field Office, and Skip Ritter, Project Coordinator with the Elko Field Office, express their appreciation to Rick Tholen, 5900 Project Lead, for his valued support and assistance in making this project possible. BLM Library Denver Federal Center Bldg. 50, OC-521 P.O. Box 25047 Denver, CO 80225 TABLE OF CONTENTS ACKNOWLEDGEMENTS TABLE OF CONTENTS i LIST OF TABLES il LIST OF FIGURES iv ABSTRACT vii INTRODUCTION AND STUDY AREA 1 METHODS 7 RESULTS AND SITE ANALYSES 10 Stag Mountain 10 Tuscarora Mountains 69 Adobe Mountains 81 DISCUSSION AND CONCLUSIONS 102 MANAGEMENT RECOMMENDATIONS „ 108 LITERATURE CITED 114 APPENDIX A - - Project Maps APPENDIX B - - Project Data Sheets APPENDIX C - - Project Color Slides ttl LIST OF TABLES Page Table 1. Aspen stand parameters on the Deeth Allotment, Connors Basin Field 12 2. Age and diameter of aspen on the Deeth Allotment, Connors Basin Field 15 3. Height of browsed and unbrowsed aspen suckers in recently burned aspen stands on the Deeth and Stag Mountain Allotments 16 4. Understory species composition of aspen stands on the Deeth Allotment, Connors Basin Field 17 5. Aspen stand parameters on the Deeth Allotment, Hanks Creek Basin Field 26 6. Age and diameter of aspen on the Deeth Allotment, Hanks Creek Basin Field 27 7. Understory species composition of aspen stands on the Deeth Allotment, Hanks Creek 28 Basin Field 8. Aspen stand parameters on the Stag Mountain Allotment, McIntyre Field 35 9. Age and diameter of aspen on the Stag Mountain Allotment, McIntyre Field 37 10. Understory species composition of aspen stands on the Stag Mountain Allotment, McIntyre Field 38 11. Aspen stand parameters in the Tuscarora Mountains 70 12. Age and diameter of aspen in the Tuscarora Mountains 71 13. Understory species composition of aspen stands in the Tuscarora Mountains 72 14. Aspen stand parameters in the Adobe Mountains 82 15. Age and diameter of aspen in the Adobe Mountains 84 16. Understory species composition of aspen stands in the Adobe Mountains 85 w LIST OF FIGURES Figure Page 1. General location of aspen study sites in north-central Nevada 6 2. Unburned aspen stand EK-214 in the Connors Basin Field, Deeth Allotment 20 3. Unbumed aspen stand EK-227 in the Connors Basin Field, Deeth Allotment 21 4. Burned aspen stand EK-232 in the Connors Basin Field, Deeth Allotment 22 5. Aspen stand EK-217 in the Connors Basin Field, Deeth Allotment 23 6. Aspen stand EK-228 in the Connors Basin Field, Deeth Allotment 24 7. Aspen stand EK-209 inside the East Hanks Creek Exclosure, Hanks Creek Basin Field, Deeth Allotment 29 8. Aspen stand EK-21 1 inside the Antelope Basin Exclosure, Hanks Creek Basin Field, Deeth Allotment 30 9. Aspen sucker inside the West Hanks Creek Exclosure, Hanks Creek Basin Field, Deeth Allotment 31 10. Aspen stand EK-212 outside the Antelope Basin Exclosure, Hanks Creek Basin Field, Deeth Allotment 32 11. Aspen stand EK-240, McIntyre Field, Stag Mountain Allotment 40 12. Aspen stand EK-247, McIntyre Field, Stag Mountain Allotment 41 13. Aspen stand EK-249, McIntyre Field, Stag Mountain Allotment 42 14. Aspen stand EK-251 McIntyre Field, Stag Mountain Allotment 43 , 15. Aspen stand EK-239 viewed northwest, McIntyre Field, Stag Mountain Allotment 44 16. Aspen stand EK-239 viewed northeast, McIntyre Field, Stag Mountain Allotment 45 17. Fenceline contrast, Cheveller Exclosure, McIntyre Field, Stag Mountain Allotment....47 18. Aspen stand EK-241 inside the Cheveller Exclosure, McIntyre Field, Stag Mountain Allotment 48 19. Browsed aspen sucker inside the Cheveller Exclosure 49 V 20. A recent beaver dam inside the Cheveller Exclosure 50 21. Aspen stand EK-242 inside the Cheveller Exclosure 51 22. Aspen stand EK-243 inside the Cheveller Exclosure 52 23. Recent beaver activity on an unnamed tributary to the South Fork of Hanks Creek, Connors Basin Field, Deeth Allotment 54 24. Old beaver activity on an unnamed tributary to the South Fork of Hanks Creek, Connors Basin Field, Deeth Allotment 55 25. Old beaver activity on Connors Creek, Connors Basin Field, Deeth Allotment 56 26. Old beaver activity on upper Cottonwood Creek, McIntyre Field, Stag Mountain Allotment 57 27. Allotment boundary comparison 59 28. Aspen stand EK-234, Connors Basin Field, Deeth Allotment 60 29. Aspen stand EK-233, McIntyre Field, Stag Mountain Allotment 61 30. Aspen stand EK-234, Connors Basin Field, Deeth Allotment 62 31. Aspen along an unnamed tributary to Pole Creek, Indian Creek Field, Devils Gate Allotment 64 32. Aspen along Pole Creek on the Pole Creek Allotment 66 33. Close up of a burned aspen stand along Pole Creek 67 34. An old beaver dam on Pole Creek, Pole Creek Allotment 68 35. A typical aspen stand along Nelson Creek 73 36. Typical aspen stands along Lewis Creek 74 37. Aspen in upper Toe Jam Creek 75 38. Close up of aspen in upper Toe Jam Creek 76 39. Aspen stand EK-253 in upper Toe Jam Creek 77 40. Aspen in upper Rock Creek 78 41 Aspen in upper Big Cottonwood Canyon 79 . VI 42. Close up of a heavily grazed aspen stand along upper Dry Creek in the Tuscarora Mountains 80 43. Aspen stand EK-264 in the Adobe Mountains 87 44. Close up aspen stand EK-264 in the Adobe Mountains 88 45. Aspen stand EK-270 in the Adobe Mountains 89 46. Aspen stand EK-272 in the Adobe Mountains 90 47. A de facto exclosure in aspen stand EK-272 in the Adobe Mountains 91 48. Aspen inside Long Canyon Exclosure number one 92 49. Close up of aspen inside Long Canyon Exclosure number one 93 50. Aspen inside Coal Mine Canyon Exclosure number two 94 51. Aspen inside Coal Mine Canyon Exclosure number three 95 52. Typical riparian conditions in the Adobe Mountains 96 53. Fenceline contrast at Coal Mine Canyon Exclosure number one 97 54. Ungrazed riparian area inside Coal Mine Canyon Exclosure number one 98 55. Grazed riparian area below Coal Mine Canyon Exclosure number one 99 56. Soil erosion in the Adobe Mountains 100 57. Close-up of sheet erosion in Long Canyon 101 VII ABSTRACT Aspen is of special concern in the West because the species does not commonly grow from seed due to its demanding seed-bed requirements. It is thought that environmental conditions have not been conducive to seedling growth and clonal establishment since shortly after the glaciers retreated 10,000 or more years ago. Hence, aspen clones found in north-central Nevada today have likely maintained their presence on those sites for thousands ofyears via vegetative regeneration; i.e. root sprouting. In addition, aspen communities support an array of other species and have the highest biodiversity of any upland forest type in the West. This is especially true in north-central Nevada where many aspen stands are associated with riparian habitats. Aspen, though, has been declining in Nevada and throughout the Intermountain West since shortly after European settlement. The reasons for this have been attributed to climatic change, fire suppression, normal plant succession, wild ungulate browsing, and/or grazing by domestic livestock. To test these hypotheses and to determine the status of aspen on BLM administered lands in north-central Nevada, measured 75 representative aspen stands I on Stag Mountain and in the Tuscarora and Adobe Mountains. also measured all aspen- I containing exclosures in those areas. The exclosures were originally built to study the effect of livestock use, but because the general climate is the same inside and outside the fenced plots, the exclosures can also be used to evaluate the climatic change hypothesis. The same is true of de facto exclosures created by fallen aspen trees or other physical barriers. VIII Many aspen stands in north-central Nevada have not produced new stems greater than 6 feet tall in nearly 100 years and many stands are in very poor condition. The status and trend of aspen communities in north-central Nevada, however, is not related to climatic variation, fire suppression, forest succession, or browsing by mule deer. Instead, the condition of individual aspen communities is related to past and present levels of livestock grazing. That is, aspen is declining throughout most of north-central Nevada due to repeated browsing of aspen suckers by cattle and/or domestic sheep - - repeated browsing eliminates sucker height growth, which prevents their maturation into aspen saplings and trees. Without stem replacement, aspen clones are consigned to extinction. This cause and effect relationship is most clearly demonstrated inside and outside exclosures. In all cases where it was protected, aspen successfully regenerated without fire or other disturbance, while on adjacent, outside plots, aspen continued to decline. Aspen in north-central Nevada also experienced major regeneration events on allotments where livestock use was reduced. Fire can be used to stimulate aspen regeneration, but burned aspen stands must be rested for several years until the majority of new stems are beyond the reach of livestock. Beaver-felled aspen also need to be protected or repeated livestock use will eliminate those clones, as has already happened on some allotments. Thus, to reverse the decline of aspen in north-central Nevada it will be necessary to more closely manage livestock. Depending on individual sites and the present condition of aspen, it may be necessary to fence some stands and/or restrict livestock to only early- season grazing. If aspen does not respond to those measures, it may be necessary to reduce AUM numbers on some allotments. It is also recommended that BLM establish