Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. S 4 i \ f i | A99.y F764Un outhwest Great Plains Research Note RM-498 April 1990 USDA Forest Service Rocky Mountain Forest and Range Experiment Station Permanent Plots for Quantifying Damage Caused by Western Dwarf Mistletoes and Their Spread and Intensification Frank G. Hawksworth and Michael A. Marsden 1 This note describes 40 permanent plot installations in the West that have been established to monitor the effects of dwarf mistletoes {Arceuthobium spp.) on growth and mortality in infested conifer stands or to quantify spread and intensification of the parasites. The distribu- tion of the plots by host species is: interior ponderosa pine (1 1 ), coastal ponderosa pine and Jeffrey pine (10), lodgepole pine (5), Douglas-fir (6), true firs (4), western larch (2), western hemlock (1), and spruce (1). Keywords: Dwarf mistletoe, Arceuthobium, damage, spread, intensifi- cation. This compilation, which we initiated after a 1989 meeting that involved various units of the Forest Serv- ice, U.S. Department of Agriculture, lists the active per- manent plots in the West that are available to: (1) monitor the spread and intensification of dwarf mistletoes, and/or (2) quantify the effects of these pathogens on the mor- tality, growth, and yield of trees or stands. The plots are listed by dwarf mistletoe and host species, and the unit that established the study or is maintaining the plot records is indicated. Also, publications or reports re- lating to each plot installation are given. This informa- tion should be useful to those attempting to develop and calibrate growth and yield models for dwarf mistletoe- infested stands in the West. When new plots are established, consideration should be given to meeting the standards for permanent plots as described by the USDA Forest Service (1989), al- though additional dwarf mistletoe information is needed. In addition to the plots described here, permanent Forest Inventory plots may provide information on dwarf mistletoe intensification and damage in some areas (Bol- singer 1978). I. ARCEUTHOBIUM VAGINATUM ssp. CRYPTO- PODUM ON INTERIOR PONDEROSA PINE (PI- NUS PONDEROSA var. SCOPULORUM) ''Plant Pathologist and Biometrician, Rocky Mountain Forest and Range Experiment Station. Headquarters is in Fort Collins, in coopera- tion with Colorado State University. 1. Fort Valley Experimental Forest, Arizona: 24 plots with 3 growing stock levels (60, 80, and 100 square feet per acre) x 2 replicates and 4 intensities of dwarf mistletoe infection in a 60-year-old, even-aged stand. (Note: 2 plots were destroyed by fire.) Established in 1978-79, measured in 1983 and 1988. Rocky Mountain Station. Reference: Hawksworth and Geils (1985). 2. Fort Valley Experimental Forest, Arizona: 9 treated plots (each 25 acres) plus 3 untreated plots (each 10 acres) in virgin ponderosa pine; 3 dwarf mistletoe treatments (limited, unlim- ited, and light improvement selection) x 3 replicates. Established in 1952, last examined in 1977. The 225-acre treated area was logged after the 1977 examination, but the 3 check plots remain undisturbed. Rocky Mountain Station. References: Heidmann (1968, 1983), Herman (1961). 3. Fort Valley Experimental Forest, Arizona: 3 plots totalling 19 acres in uneven-aged ponder- osa pine; sanitized by pruning and felling in 1933. Examined in 1950 and 1970. Rocky Mountain Station. Reference: Gill and Hawks- worth (1954). 4. Fort Valley Experimental Forest, Arizona: 16 plots (2.5 acres) in a virgin ponderosa pine stand (G. A. Pearson Natural Area); 3,000 in- 1 dividual trees evaluated at 5-year intervals from 1920 to 1970. The records include dwarf mis- tletoe but the infestation is light (range from no infection to 6% of the trees infected on the 2.5 acre plots in 1920). Rocky Mountain Station and Northern Arizona University. References: Avery et al. (1976), Linhart (1988). 5. Grand Canyon National Park, Arizona: 7 plots (4 treated and 3 untreated) totalling 35 acres, in uneven-aged and even-aged ponderosa pine. Established in 1950-52, examined in 1955, 1961, 1970, and 1982 (also 1 plot examined in 1988); next examination planned for 1990. Rocky Mountain Station. References: Dixon and Hawksworth (1979), Hawksworth and Geils (1990), Lightle and Hawksworth (1973), Maffei (1984). 6. Mescalero Apache Reservation, New Mexico: 7 plots totalling 64 acres in even-aged and uneven-aged ponderosa pine. Established in 1945-1951, examined in 1955, 1961, 1970, and 1982; next examination planned for 1990. Rocky Mountain Station. Reference: Hawks- worth and Lusher (1956). 7. Bryce Canyon National Park, Utah: 5 plots totalling 6 acres in uneven-aged ponderosa pine and mixed limber pine (Pinus flexilis)- bristlecone pine (P. Jongaeva)-ponderosa pine types (1 plot destroyed by park development). Established in 1952, last examined in 1987. Rocky Mountain Station. References: none. 8. Manitou Experimental Forest, Colorado: 30 plots (0.1-0.4 acre) in even-aged ponderosa pine pole stands; thinned to various growing stock levels in 1978. Last measured in 1988. Rocky Mountain Station. References: none. 9. Manitou Experimental Forest, Colorado: 20 plots (1-2.5 acres) in mature uneven-aged pon- derosa pine; various silvicultural applications, including no treatment. Established in 1978, last measured in 1988. Rocky Mountain Sta- tion. Reference: Maffei (1989). 10. Roosevelt National Forest, Colorado: 30 plots (0.1-0.4 acre) in even-aged pole stands; thinned to various growing stock levels in 1978-79. Last examined in 1988-89. Rocky Mountain Station. References: none. 11. Apache-Sitgreaves National Forest, Arizona: 553 ponderosa pines tagged in 1979 in virgin mixed-conifer stands on the 1,800-acre Willow- Thomas Creek Watershed. Trees were rerated for dwarf mistletoe in 1989. Rocky Mountain Station. Reference: Gottfried (1978). II. ARCEUTHOBIUM CA MP YLOPODUM ON COASTAL PONDEROSA PINE {PINUS PONDER- OSA var. PONDEROSA) AND JEFFREY PINE (PI- NUS JEEEREYl) 1. Eastern Washington State Lands: 32 plots (0.1-acre) in even-aged pole stands. Most plots are in pure ponderosa pine but about one-fifth are mixed ponderosa pine-Douglas-fir. The Douglas-fir is also infected by dwarf mistletoe. Trees of both species were thinned and sani- tized for dwarf mistletoe in 1974. Plots were remeasured in 1979 and in 1986. Ken Russell, Washington Department of Natural Resources, Olympia. References: Russell (1980, 1987). 2. Eastern Oregon National Forests: 6 thinning plots in even-aged ponderosa pine established in 4 areas in 3 national forests — Hahn Springs on the Ochoco National Forest (1 plot with 53 trees measured in 1976 and 1982), 2 plots on the Malheur National Forest (Fawn Creek with 90 trees measured in 1970, 1975, and 1982 and Sunshine with 100 trees measured in 1970, 1975, and 1982), and 3 plots near Beatty in the Fremont National Forest (with 95, 89, and 98 trees measured in 1970-72, 1975, and 1982). Plots established by the Pacific Northwest Forest and Range Experiment Station; now maintained by Region 6, Forest Pest Manage- ment. Summary of data from all plots made by Tom Gregg of Region 6, Forest Pest Manage- ment, in 1984. Copies of tree records also at Rocky Mountain Station. References: none. 3. Pringle Falls Experimental Forest, Oregon: 48 plots (0.22-acre) (4 thinning levels x 12 repli- cates) established by Lew Roth of Oregon State University in 1966; mistletoe data recorded an- nually between 1966 and 1980. tree data re- corded in 1968, 1976, and 1988. Assistance in the analyses of the 1988 readings being pro- vided by the Rocky Mountain Station. Refer- ences: none. 4. Pringle Falls Experimental Forest. Oregon: 6 plots (0.19-acre) established by Lew Roth of Oregon State University in mature ponderosa pine with a sapling understory in 1957; infect- ed overstory removed and understory thinned to 48 trees per plot (250 trees per acre). Plots measured in 1959 and 1969. Pacific Northwest Station. References: Barrett and Roth (1985). Roth and Barrett (1985). 5. Pringle Falls Experimental Forest. Oregon: an outplanting in 3 replications testing the resist- ance to dwarf mistletoe of each of 12 parent ponderosa pine trees presumably differing in resistance to dwarf mistletoe. Established in 1969 by Lew Roth of Oregon State University. Mistletoe data and tree measurements recorded in 1989. References: none. 6. Eastside Oregon and Washington: thinning plots established in ponderosa pine in central and eastern Washington and Oregon; thinning levels were 82. 128. and 174 trees per acre, which equated to 45. 70. and 95 square feet of basal area per acre based on an average d.b.h. of 10 inches, respectively. A total of 141 plots established: 27. 39. 62. and 13 plots measured for baseline data in 1980. 1981. 1982. and 1983. respectively. First 5-year measurement taken in 1985. 1986. 1987. and 1988. Plots established 2 by the Pacific Northwest Station, and 5-year records taken by Forest Pest Management, Region 6. Data are on file at the National Com- puter Center at Fort Collins but are not yet ana- lyzed. References: none. 7. California and Nevada Recreational Areas: 526 tagged ponderosa pine and Jeffrey pines in 3 campgrounds on the Lassen National Forest, California; 1,545 tagged Jeffrey pines at the Nevada Beach Campground, Tahoe National Forest, Nevada, and 974 tagged Jeffrey pines at Laguna Mountain Campground, Cleveland Na- tional Forest, California. Established in 1973-74 to monitor mortality in mistletoe-infected trees and changes in mistletoe intensification. Pacific Southwest Region and Pacific Southwest Sta- tion. References: Scharpf and Vogler (1986), Scharpf et al. (1988); Vogler and Scharpf (1981). 8. Lassen National Forest, California: 7 plots (1-3 acres) established in the Manzanita Chute area in 1964 to monitor spread and intensification of dwarf mistletoe in understory Jeffrey pines. Pacific Southwest Station. References: Par- meter and Scharpf (1972), Scharpf and Par- meter (1971). 9. Lassen National Forest, California: 7 plots (1-acre) established in 1979 at Grays Valley, Ea- gle Lake Ranger District, to measure the effects of thinnings to various densities in mistletoe- infested ponderosa pine. Pacific Southwest Region, Forest Pest Management. Reference: Fiddler et al. (in prep.). 10. Sierra Nevada, California and Nevada: 4 Jeffrey pine progeny tests were established in 1940 by the Institute of Forest Genetics. These are now being used to quantify resistance to Arceutho- bium campylopodum. Pacific Southwest Sta- tion. Reference: Scharpf (1987). III. ARCEUTHOBIUM AMERICANUM ON LODGE- POLE PINE (PINUS CONTORT A var. LATIFOLIA) 1. Targee National Forest, Idaho: 16 plots (0.1-0.2 acre) in even-aged pole stands; thinned to var- ious spacings in 1983. Last measured in 1988. J. Hoffman, Intermountain Region, Boise; as- sistance in the 1988 re-examination provided by the Rocky Mountain Station. References: none 2. Gallatin National Forest, Montana: 36 plots (0.5-acre) in even-aged pole stands; 3 dwarf mistletoe treatments x 4 thinning levels x 3 replicates. Established in 1971, remeasured in 1984 and 1989. Remeasurements made in 1989 by the Rocky Mountain Region and Rocky Mountain Station. Northern Rocky Mountain Region. References: Dooling et al. (1986), John- son et al. (1986). 3. Fraser Experimental Forest, Colorado: 28 plots (0.4-acre) in even-aged, 60- to 70-year-old, pole-sized stands; thinned to various growing stock levels (40, 80, 100, 120, and 160) in 1976-1981. Plots remeasured at 5-year inter- vals. Rocky Mountain Station, Multiresource Management and Pest Assessment Technolo- gy Projects. References: Alexander and Edmin- ster (1981), Alexander et al. (1985). 4. Roosevelt National Forest, Colorado: 19 plots (0.3-1.0 acre) near Pingree Park in even-aged pole stands, thinned to various levels in 1949-1981. Last remeasured in 1987. Colora- do State University and Rocky Mountain Sta- tion. References: none. 5. Routt National Forest, Colorado: 37 plots (0.5-acre) in even-aged pole stands; sanitized for dwarf mistletoe and thinned in 1965-66. Last remeasured in 1987. Rocky Mountain Sta- tion and Rocky Mountain Region. References: Hawksworth et al. (1977, 1987). ARCEUTHOBIUM DOUGLASU ON DOUGLAS-FIR [PSEUDOTSUGA MENZIESU var. GLAUCA) 1. Lolo National Forest, Montana: 25 plots (0.25-acre) in even-aged pole stands; 3 dwarf mistletoe treatments x 4 thinning levels x 2 replicates, plus 1 extra plot. Established in 1970, remeasured in 1983 and 1988. Northern Rocky Mountain Region. Reference: Dooling et al. (1986). 2. Okanogan and Malheur National Forests: study of response of pole-sized Douglas-fir and dwarf mistletoe to thinning; 9 plots with 227 trees es- tablished on the Malheur National Forest, Ore- gon, in 1973, remeasured in 1983 and 1988; 6 plots with 144 trees established on the Okano- gan National Forest, Washington, in 1974, remeasured in 1983 and 1989. R. Tinnin, Port- land State University, assisted in the 1988 and 1989 remeasurements provided by the Rocky Mountain Station. References: Knutson and Tinnin (1986), Tinnin (1988, 1989). 3. Apache-Sitgreaves, Carson, Lincoln, and Santa Fe National Forests (Arizona and New Mexi- co): study of permanent inventory plots to quantify Douglas-fir growth, mortality, and spread and intensification in unmanaged, mixed conifer stands; 54 plots with 216 Douglas-firs and 816 trees of other species. Plots first measured in 1977 and remeasured in 1987; remeasurement planned for 1997. Rocky Mountain Station. Reference: Geils and Shaw (in prep.). 4. Apache-Sitgreaves National Forest, Arizona: 1,248 Douglas-fir trees tagged in 1979 in vir- gin mixed-conifer stands on the 1,800-acre Willow-Thomas Creek Watershed. Trees to be rerated for dwarf mistletoe in 1989. Rocky Mountain Station. Reference: Gottfried (1978). 5. Wallowa- Whitman, Wenatchee, and Okanogan National Forests (Washington and Oregon): study of interaction of dwarf mistletoe and western spruce budworm on Douglas-fir growth, mortality, spread, and intensification in unmanaged stands — 94 stands with 1,559 3 Douglas-fir. Plots measured in 1977 and re- measured in 1987; remeasurement planned in 1997. Pacific Northwest Station; Forest Pest Management, Pacific Northwest Region; and Rocky Mountain Station. Reference: Filip et al. (in prep.). 6. Eastern Washington State Lands: 32 plots (0.1-acre) in even-aged pole stands. Most plots are in pure ponderosa pine but about one-fifth are mixed ponderosa pine-Douglas-fir. The Douglas-fir is also infected by dwarf mistletoe. Trees of both species were thinned and sani- tized for dwarf mistletoe in 1974. Plots were remeasured in 1979 and in 1986. Ken Russell, Washington Department of Natural Resources, Olympia. References: Russell (1980, 1987). V. ARCEUTHOBIUM ABIETINUM ON WHITE FIR [ABIES CONCOLOR) AND RED FIR (ABIES MAG- NIFICA) 1. Thinning plots in the Klamath, Lassen, Stan- islaus, Tahoe, and Sequoia National Forests, California: 37 plots in white and red fir estab- lished in 1979-1981. Plots established by the Pacific Southwest Station and being main- tained by the Pacific Southwest Region. Refer- ences: none. 2. California National Forests: 5, 100-tree plots to quantify dwarf mistletoe intensification and tree growth in fully released, advanced red fir 6-20 inches d.b.h. Plots established in 1972 on the Klamath, Lassen (2), Stanislaus, and Sier- ra National Forests. Pacific Southwest Station. References: none. 3. Stanislaus National Forest, California: 3 plots (1 with 50 trees and 2 with 80 trees each) in cutover, released pole-sized red fir stands with dwarf mistletoe. Two plots established in 1970 and 1 in 1976. Pacific Southwest Station. Refer- ences: none. 4. Sierra Nevada, California: Plots with various numbers of trees established in 1958 on the Stanislaus National Forest and Latour State Forest (near Mt. Lassen) to quantify intensifi- cation of dwarf mistletoe in inoculated red and white firs. Pacific Southwest Station and Uni- versity of California. Reference: Parmeter and Scharpf (1989). VI. ARCEUTHOBIUM LARICIS ON WESTERN LARCH (LARIX OCCIDENTALS) 1. Growden Area, Colville National Forest. Wash- ington: 40 plots (0.5-acre) in even-aged stands: 4 levels of dwarf mistletoe removal x 5 thin- ning treatments x 2 replicates. Established in 1970-73 by the Intermountain Station, remeas- ured in 1978, 1983, and 1988; 20-year results being analyzed by the Rocky Mountain Station. References: none. 2. Coram Experimental Forest. Montana: 55 tagged western larch inoculated in a 15-year- old stand. Established in 1969 by the Inter- mountain Station; remeasured in 1978 and 1988; 20-year results are being analyzed at the Rocky Mountain Station. Reference: Wicker and Wells (1983). 3. Northeastern Oregon, Boise-Cascade Lands: study of the effects of commercial thinning on volume growth of dwarf mistletoe-infected larch; 554 western larch tagged in a stand near Elgin. Tree volumes were measured in 1970 and 1984; dwarf mistletoe and tree vigor (cam- bial electrical resistance) were measured in 1986. Pacific Northwest Station. Reference: Filip et al. (1989). Vn. ARCEUTHOBIUM TSUGENSE ON WESTERN HEMLOCK [TSUGA HETER OPHYLLA ) 1. Thome Bay, Prince of Wales Island, Alaska: study on rate of spread and intensification of mistletoe from overstory residual western hem- locks into reproduction. In 1981. 19 plots (0.26 ha) established in reproduction of 2 age classes: plots were remeasured in 1983. 1985. and 1987; another examination is planned for 1990. Alaska Region. Juneau. References: Hennon and Shaw (1988), Shaw (1982), Shaw and Hen- non (in prep.). VIII. ARCEUTHOBIUM MICROCARPUM ON ENGEL- MANN SPRUCE [PICEA ENGELMANNII) AND BLUE SPRUCE (PICEA PUNGENS) 1. Apache-Sitgreaves National Forest, Arizona: 554 Engelmann spruce and 67 blue spruce tagged in 1979 in virgin, mixed-conifer stands on the Willow-Thomas Creek Watershed. Trees were rerated for dwarf mistletoe in 1989. Rocky Mountain Station. Reference: Gottfried (1978). Literature Cited Alexander, R. R.; Edminster. C. B. 1981. Management of lodgepole pine in even-aged stands in the central Rocky Mountains. Res. Pap. RM-229. Fort Collins. CO: U.S. Department of Agriculture. Forest Sendee. Rocky Mountain Forest and Range Experiment Station, lip. Alexander, R. R.; Troendle. C. A.: Kaufmann. M. R.; Shepperd, W. D.; Crouch. G. L.; Watkins. R. K. 1985. The Fraser Experimental Forest. Colorado: research program and published research 1937-1985. Gen. Tech. Rep. RM-118. Fort Collins. CO: U.S. Department of Agriculture. Forest Sendee. Rocky Mountain Forest and Range Experiment Station. 46 p. Avery, C. G.; Larson. F. R.; Schubert. G. H. 1976. Fifty- year records of virgin stand development in south- western ponderosa pine. Gen. Tech. Rep. RM-22. Fort Collins, CO: U.S. Department of Agriculture. Forest Service, Rocky Mountain Forest and Range Experi- ment Station. 71 p. Barrett, J. W; Roth. L. F. 1985. Response of dwarf mistletoe-infested ponderosa pine to thinning: 1. sap- ling growth. Res. Pap. PNW-330. Portland. OR: U.S. Department of Agriculture. Forest Sendee. Pacific Northwest Forest and Range Experiment Station. 15 p. Bolsinger, C. L. 1978. The extent of dwarf mistletoe in six principal softwoods in California. Oregon, and Wash- 4 ington, as determined from Forest Survey records. Gen. Tech. Rep. PSW-31. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 45-61. Dixon, G. E.; Hawksworth, F. G. 1979. A spread and in- tensification model for southwestern dwarf mistletoe in ponderosa pine. Forest Science. 24: 43-52. Dooling, O. J.; Johnson, R. R.; Eder, R. G. 1986. Growth impact, spread, and intensification of dwarf mistletoe in Douglas-fir and lodgepole pine in Montana. Pest Mgmt. Rep. 86-6. Missoula, MT: U.S. Department of Agriculture, Forest Service, Northern Region. 11 p. Filip, G. M.; Colbert, J. J.; Parks, C. A.; Seidel, K. W. 1989. Effects of thinning on volume growth of western larch infected with dwarf mistletoe in northeastern Oregon. Western Journal Applied Forestry. 4: 143-145. Gill, L. S.; Hawksworth, F. G. 1954. Dwarf mistletoe control in southwestern ponderosa pine forests under management. Journal of Forestry. 52: 347-353. Gottfried, G. J. 1978. Five-year growth and development in a virgin Arizona mixed conifer stand. Res. Pap. RM-203. Fort Collins, CO: U.S. Department of Agricul- ture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 22 p. Hawksworth, F. G.; Geils, B. W. 1985. Vertical spread of dwarf mistletoe in thinned ponderosa pine in Ari- zona. Res. Note RM-460. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 3 p. Hawksworth, F. G.; Geils, B. W. 1990. How long do dwarf mistletoe infected ponderosa pines live? Western Journal of Applied Forestry. [In press.] Hawksworth, F. G.; Hinds, T. E.; Johnson, D. W.; Lan- dis, T. D. 1977. Silvicultural control of dwarf mistle- toe in young lodgepole pine stands. Tech. Rep. R2-10. Lakewood, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Region, Forest Insect and Disease Management. 12 p. Hawksworth, F. G.; Johnson, D. W.; Geils, B. W. 1987. Sanitation thinning in young, dwarf mistletoe- infested, lodgepole pine stands. Gen. Tech. Rep. RM-149. Fort Collins, CO: U.S. Department of Agricul- ture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 218-219. Hawksworth, F. G.; Lusher, A. D. 1956. Dwarf mistle- toe survey and control on the Mescalero Apache Reser- vation, New Mexico. Journal of Forestry. 54: 384-390. Heidmann, L. J. 1968. Silvicultural control of dwarf mistletoe in heavily infected ponderosa pine in the Southwest. Res. Pap. RM-36. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, lip. Heidmann, L. J. 1983. Silvicultural control of dwarf mis- tletoe in southwestern ponderosa pine. Res. Note RM-433. Fort Collins, CO: U.S. Department of Agricul- ture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 4 p. Hennon, P.; Shaw C. G., III. 1988. Hemlock dwarf mis- tletoe demonstration area, Thome Bay, Prince of Wales Island, Alaska. Leaflet R10-TP-5. Juneau, AK: U.S. Department of Agriculture, Forest Service, Alaska Region. 9 p. Herman, F. R. 1961. Silvicultural control of dwarf mis- tletoe on southwestern ponderosa pine. Station Pap. 62. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Ex- periment Station. 20 p. Johnson, R. R.; Dixon, G. E.; Schroeder, D. I. 1986. The south central Oregon/northeastern California prog- nosis (SORNEC). Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Washington Office Timber Management. 45 p. Knutson, D.; Tinnin, R. 1986. Effects of dwarf mistle- toe on the response of young Douglas-fir to thinning. Canadian Journal of Forest Research. 16: 30-35. Lightle, P. C; Hawksworth, F. G. 1973. Control of dwarf mistletoe in a heavily used ponderosa pine recreation forest: Grand Canyon, Arizona. Res. Pap. RM-106. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experi- ment Station. 22 p. Linhart, Y. B. 1988. Ecological and evolutionary studies of ponderosa pine in the Rocky Mountains. In: Baum- gartner, D. M.; Lotan, J. E., eds. Ponderosa pine, the species and its management: proceedings of the sym- posium; 1987 September 29-October 1; Pullman, WA. Pullman, WA: Washington State University, Cooper- ative Extension: 77-89. (See p. 81.) Maffei, H. 1984. Control of dwarf mistletoe at the Grand Canyon: results after a third of a century. In: Proceed- ings of the 32nd western international forest disease work conference; 1984 September 25-28; Taos, NM: 59-60. Maffei. H. M. 1989. Southwestern dwarf mistletoe damage to multi-aged ponderosa pine stands of the Colorado Front Range. Fort Collins, CO: Colorado State University, Department of Plant Pathology and Weed Science. 112 p. Ph.D. dissertation. Parmeter, J. R., Jr.; Scharpf. R. F. 1972. Spread of dwarf mistletoe from discrete seed sources into young stands of ponderosa and Jeffrey pines. Res. Note PSW-269. Berkeley, CA: U.S. Department of Agriculture. Forest Service, Pacific Southwest Forest and Range Experi- ment Station. 5 p. Parmeter. J. R.. Jr.: Scharpf. R. F. 1989. Dwarf mistle- toe in red and white firs in California — 23 to 28 years after inoculation. Res. Note PSW-406. Berkeley. CA: U.S. Department of Agriculture. Forest Service. Pa- cific Southwest Forest and Range Experiment Station. 5 p. Roth. L. F.; Barrett, J. W. 1985. Response of dwarf mistletoe-infested ponderosa pine to thinning: 2. Dwarf mistletoe propagation. Res. Pap. PNW-331. Portland, OR: U.S. Department of Agriculture. Forest Service, Pacific Northwest Forest and Range Experi- ment Station. 20 p. Russell. K. 1980. Dwarf mistletoe control in eastern Washington ten years after treatment. In: Proceedings of the 27th western international forest disease work conference; 1979 September 25-28: Salem. OR: 98-104. 5 Russell, K. 1987. Dwarf mistletoe control in eastern Washington ponderosa pine and Douglas-fir stands seventeen years after treatment. In: Proceedings of the 35th western international forest disease work confer- ence; 1987 August 18-21; Nanaimo, British Colum- bia: 59-65. Scharpf, R. F. 1987. Resistance of Jeffrey pine to dwarf mistletoe. In: Weber, H. C; Forstreuter, W., eds. Proceedings of the international symposium on para- sitic flowering plants; 1987 August 2-7; Marburg, West Germany: 745-753. Scharpf, R. F.; Parmeter, J. R., Jr. 1971. Seed produc- tion and dispersal by dwarf mistletoe in overstory Jeffrey pines in California. Res. Note PSW-247. Ber- keley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experi- ment Station. 6 p. Scharpf, R. F.; Smith, R. S.; Vogler, D. 1987. Pruning dwarf mistletoe brooms reduces stress on Jeffrey pines, Cleveland National Forest, California. Res. Pap. PSW-186. Berkeley, CA: U.S. Department of Agricul- ture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 7 p. Scharpf, R. F.; Smith, R. S.; Vogler, D. 1988. Manage- ment of western dwarf mistletoe in ponderosa and Jeffrey pines in forest recreation areas. Gen. Tech. Rep. PSW-103. Berkeley, CA: U.S. Department of Agricul- ture, Forest Service, Pacific Southwest Forest and Range Experiment Station, lip. Scharpf, R. F.; Vogler, D. 1986. Western dwarf mistle- toe infects understory Jeffrey pines on Cleveland Na- tional Forest, California. Res. Note PSW-386. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experi- ment Station. 2 p. Shaw, C. G., III. 1982. Development of dwarf mistletoe in western hemlock regeneration in southeast Alaska. Canadian Journal of Forest Research. 12: 482-488. Tinnin, R. O. 1988. Responses of dwarf mistletoe and hosts following thinning in immature stands of Douglas-fir on the Malheur National Forest, Oregon. Final Report: Cooperative Agreement 18-C8-445 with Portland State University, Department of Biology. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experi- ment Station. 39 p. Tinnin, R. O. 1989. Responses of dwarf mistletoe and hosts following thinning in immature stands of Douglas-fir on the Okanogan National Forest, Washington. Final Report: Cooperative Agreement 28-C9-504 with Portland State University, Department of Biology. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 39 p. U.S. Department of Agriculture, Forest Service. 1989. Timber permanent plot handbook. For. Serv. Handb. 2409.19. Washington, DC: U.S. Department of Agri- culture, Forest Service. 29 p. Vogler, D. R.; Scharpf, R. F. 1981. Dwarf-mistletoe relat- ed mortality of ponderosa and Jeffrey pines at five campgrounds in California and Nevada. For. Pest Mgmt. Report 81-28. San Francisco, CA: U.S. Depart- ment of Agriculture, Forest Service, Pacific Southwest Region. 22 p. Wicker, E. F.; Wells, J. M. 1983. Intensification and lateral spread of Arceuthobium laricis in a young stand of western larch with stocking control. Canadian Jour- nal of Forest Research. 13: 314-319. 4 \