TABLE 12.3–Relative rates of height growth in relation to intensity of infection by Arceuthobium as quantified with the 6-class dwarf mistletoe rating system (DMR)
  Percentage growth of infected trees
Arceuthobium Host class 1 class 2 class 3 class 4 class 5 class 6
A. americanum Pinus contorta 100 100 98 93 81 72
A. douglasii Pseudotsuga menziesii 94 94 84 84 75 75
A. laricis Larix occidentalis 99 99 87 87 83 83
A. vaginatum Pinus ponderosa* 100 100 96 92 89 85
Pinus ponderosa† 100 100 94 92 87 79
Note: Height growth rates of uninfected trees taken as 100%. Data for Pinus contorta infected by A. americanum represents 10-year average stand growth (Myers and others 1971). Data for Pseudotsuga menziesii infected by A. douglasii and for Larix occidentalis infected by A. laricis are average annual growth rates for individual trees grouped into 3 infection classes: less than 1/3 of crown broomed (class 1-2), 1/3 to 2/3 of crown broomed (class 3-4), and more than 2/3 of crown broomed (class 5-6) (Pierce 1960). Data for Pinus ponderosa infected by A. vaginatum subsp. crytopodum given for two bases: *10-year average stand growth (Myers and others 1976) and †total height of 55-year-old trees (Hawksworth 1961a).

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