Changes in Transpiration by Emory Oak Following Tree Harvesting

Transpiration by mature- and sprout-forms of Emory oak (Quercus emoryi) was estimated by the sapflow velocity method on two adjacent sites, one unharvested and the other harvested for fuelwood, in the oak woodlands of southeastern Arizona. There were few differences in daily transpiration between mature trees on either site; however, there were differences in transpiration between the mature trees on the two sites and the post-harvesting stump sprouts on the harvested site. The importance of these differences is shown by translating the estimates of transpiration by individual trees to a stand-basis through extrapolations of the results to inventories of stocking conditions in the vicinity of the sites sampled. On a per-hectare basis, about 1,900 liters of water were transpired by mature Emory oak on the unharvested site, while 3,150 liters of water were transpired annually by the mature trees and post-harvesting stump sprouts. One factor contributing to the greater transpiration of Emory oak in the harvested stand is likely the occurrence of a large number of vigorous post-harvesting sprouts.