Cattle grazing on conifer plantations can reduce the competition of understory vegetation with conifer seedlings and thus increase conifer growth, however, cattle may also have detrimental effects on conifer seedling growth if these plants are grazed or trampled. In southwestern Oregon, Karl and Doescher measured the aboveground growth of ponderosa pine (Pinus ponderosa) seedlings that had sustained either removal of terminal stem or bud tissue by cattle grazing and a control with no removal. In 1990, cumulative, absolute height and stem volume of seedlings that sustained terminal tissue removal were similar to control seedlings. In 1988, relative height growth was comparable between control seedlings and seedlings sustaining tissue removal in May 1987. In contrast, 1988 relative height growth was -22% for seedlings sustaining tissue removal in August 1987, compared with control seedlings. Conifer seedlings that were grazed/trampled earlier in the growing season (April or May) were more likely to recover than those grazed/trampled later in the season (August) and short term reductions in growth due to cattle grazing were overcome one to two seasons after the grazing event as long as the seedlings were not repeatedly grazed. Therefore, the authors concluded that early season cattle grazing may be used as a management tool on conifer plantations to reduce competition with understory vegetation without causing long-term damage to conifer seedlings.
Ponderosa pine aboveground growth after cattle removal of terminal tissue
conifer seedling growth
relative growth rate
stem volume growth