PARENT SESSION
Contributed Oral Session 4: Forest Management
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 514 A, Level 5, Palais des congrès de Montréal

Indicators of oak decline in an Ozark landscape.

Spetich, Martin^*,1, ¹ Southern Research Station, USDA Forest Service, Hot Springs, AR, USA

ABSTRACT- The current oak decline event occurring across the Ozark landscape in Arkansas and Missouri is severely affecting at least 120,000 ha in Arkansas alone. Results of early changes in physical tree characteristics during the oak decline event are presented. Unlike other oak decline studies permanent research inventory plots were serendipitously established at locations that later became part of a severe oak decline incident. In August of 2000, standing trees greater than 14 cm in diameter were inventoried on twenty-four 0.3025 ha plots. By late summer of 2001 oak decline symptoms became visually evident across all plot locations. In November 2001, overstory trees were remeasured. Changes in physical tree characteristics are compared among the two inventory periods. For example, trees exhibiting epicormic branching increased from 9 trees per ha in 2000 to 55 trees per ha in 2001 (p = 0.005). Standing dead trees increased from 23 trees per ha in 2000 to 51 trees per ha in 2001 (p = 0.029). This increase in epicormic branching on living trees and increase in number and size of standing dead trees were the two best indicators of oak decline by the second year. While an overall unhealthy appearance in the first year appears to be the best indicator of tree death and tree fall by the second year. However, during the first year, prior to any visually identifiable evidence, the best indicator of decline was an elevated dead to live standing tree ratio, as compared to healthy forests across the Midwest US region. These results may help in the early detection of future oak decline events in other regions.

Key words: oak, decline, forest, ozark