Foliar scorch damage was also widespread in 1999, although it occurred primarily in eastern and southeastern Missouri. Damage was observed in both years in areas near the Lake of the Ozarks in central Missouri and several isolated locations in south central and southeastern Missouri. Looking at the two years combined, it is apparent that much of the southern half of the state has been recently affected by significant drought conditions. Many cases of mortality of single or small groups of trees have been reported during 2000. Often no immediate cause has been determined, but drought effects are suspected of having played a role.
Diseases are likely to be involved in some cases.
But also, the relatively warm temperatures of the past fall and winter could be expected to cause increased moisture loss from evergreen foliage, thus increasing the already high drought stress. The impacts of the 1999-2000 drought are expected to be seen over the next several years. Oak decline has been a common problem across southern Missouri in the past, and is expected to increase during the next few years. Decline of red oak and other species is due in part to ongoing drought stress, particularly on ridge tops and south-facing slopes with thin soils. Common indicators of decline include Armillaria, Hypoxylon, two-lined chestnut borer and red oak borer.