Gambel oak root carbohydrate response to spring, summer, and fall prescribed burning

Abstract

Control of Gambel oak (Quercus gambelii Nutt.) for increased forage production and conifer regeneration is difficult because of its vigorous sprouting ability. Nonstructural root carbohydrate concentrations, generally a good indicator of sprouting potential, were measured in understory Gambel oak in a dense ponderosa pine (Pinus ponderosa Laws.) stand following prescribed fire. Carbohydrates in roots of 1- to 2-year-old sprouts after a single fire treatment were similar to those in unburned, mature oaks. Two prescribed burns, 2 years apart during the summer carbohydrate depression, caused these root reserves to remain low into fall dormancy and probably contributed to an observed oak reduction. This summer carbohydrate depression, also observed in open-grown Gambel oak, can be recognized by rapid stem growth and new leaf production.