340 Anulewicz et al.: Emerald Ash Borer Density and Canopy Dieback in Ash D-shaped exit holes made by emerging A. planipennis adults and woodpecker attacks were counted in the fall, after adult beetle emergence was complete. Woodpeckers primarily prey on prepupae, which have completed their feeding and would otherwise have a high probability of emerging as adults (Cap- paert et al. 2005b, 2005c; Lindell et al. unpublished data). The sum of adult exit holes and woodpecker attacks, there- fore, represented the cumulative number of A. planipennis larvae that developed in the area surveyed on each tree. Exit holes and woodpecker attacks were counted on the entire trunk or branch circumference in four areas of each tree: at 1.5 and 3 m (4.95 and 9.9 ft) aboveground, at the base of the lowest first order branch, and 1 m (3.3 ft) out on that branch. Areas above 1.5 m (4.95 ft) were accessed using a ladder. On each tree, an area of ≈0.26 m2 (≈2.81 ft2) was inspected at 1.5 m (4.95 ft) aboveground and 0.13 m2 (1.40 ft2) was examined on the other three sample areas {average total area of 0.65 (±0.01 standard error [SE]) m2 [7.0 (±0.11 SE ft2) per tree]}. At the Butzel site, 11 trees were less than 5 cm (2 in) in dbh, so the entire stem and all branches of each tree were examined. On average, we in- spected 0.52 {(±0.03 SE) m2 [5.60 (±0.32 SE) ft2]} on each of the small trees. Percentage of the canopy that was dead, number of A. planipennis exit holes, and number of wood- pecker attacks on A. planipennis prepupal larvae was re- corded for each area inspected on each tree. Mean A. plani- pennis density per tree was calculated by summing the total number of A. planipennis exit holes and woodpecker attacks and dividing by the total area sampled in the tree. In 2003, canopy dieback was recorded on 12 August and A. planipen- nis exit holes and woodpecker attacks were counted between 12 August and 11 October. Survey methods were modified in 2004 because related research showed that initial attacks by A. planipennis were more common in the upper canopy than on the trunk (Cap- paert et al. 2005a). Therefore, on all trees greater than 5 cm (2 in) in dbh, tree climbers inspected four to six areas be- tween 1.5 and 8.5 m (4.95 and 28.1 ft) aboveground on each tree. On average, the total area examined on each tree was 1.04 (±0.07 SE) m2 [11.19 (±0.75 SE) ft2]. Small trees [dbh <5 cm (2 in)] were completely surveyed as before. With the exception of the sample area at 1.5 m (4.95 ft) aboveground, sample areas were randomly selected each year and may or may not have overlapped with areas sampled the previous year. Counts of exit holes and woodpecker attacks in 2004 were collected on 6 August at Butzel and Larned and on 9 August at Windemere. Canopy dieback was estimated at the three sites on 13 September. In July 2004, however, four green ash trees at Larned and two green ash and one white ash tree at Butzel were felled and removed from the survey sites by the respective municipalities. Canopy dieback for these seven trees was recorded as 100% in the subsequent year’s survey. ©2007 International Society of Arboriculture Seven additional dead trees were removed in 2005, includ- ing one green ash and two white ash trees at Butzel and two green ash and two white ash trees at Windemere. The two white ash trees at Windemere were felled after dieback esti- mates were made but before exit hole and woodpecker attack data could be collected. Dieback for these five trees, there- fore, was recorded as 100% in 2005. Dieback estimates were made on 16 September 2005 at all sites, except Lakeside where leaves began falling before estimates of dieback could be made. Exit holes and woodpecker attacks on the remaining 25 green ash and 30 white ash (55 trees total) were counted on 12 October at Butzel and Windemere, 19 October at Lake- side, and 19 and 21 October 2005 at Larned. Data collected from 25 green ash and 26 white ash trees (51 trees total) at Larned and Butzel in 2003 and at Windemere in 2004 were used to assess the relationship between canopy dieback and A. planipennis density. White versus Blue Ash Woodlot Trees On 2 March 2004, two white ash and three blue ash trees were surveyed by climbers in the Superior Township woodlot. Seven to 11 areas on the main stem and branches between 1.5 and 15 m (4.95 and 49.5 ft) aboveground were examined per tree and A. planipennis exit holes and woodpecker attacks were recorded for each area. An average of 2.9 (±0.22 SE)m2 [31.2 (±2.37 SE) ft2] per tree was inspected. On 28 May 2004, before the onset of A. planipennis adult emergence, two additional white ash and two blue ash trees were felled. Four to eight intervals between 1.5 and 15 m (4.95 and 49.5 ft) aboveground were inspected on each tree. An average of 0.8 (±0.09 SE) m2 [8.6 (±0.97 SE) ft2] per tree was examined. Trees that were felled were debarked and the percentage of phloem surface area covered by A. planipennis galleries was estimated. The total number of exit holes and woodpecker attacks were summed and divided by the total area sampled for each tree. There was no significant difference between counts of A. planipennis density recorded by tree climbers and counts recorded after trees were felled (S 26.0; df1,7; P0.09). Because of the difficulty of accurately estimating dieback on tall, closed-canopy woodlot trees, die- back was not estimated for the woodlot trees. On 20 January 2005, we felled five white ash and five blue ash trees in the Plymouth Township woodlot. Five to 16 trunk and branch sections between 1.5 and 17 m (4.95 and 56.1 ft) aboveground were removed from each tree and transported to the laboratory for inspection and debarking. Average area sampled per tree was 1.4 (±0.21 SE) m2 [15.1 (±2.26 SE) ft2]. Number of A. planipennis exit holes, woodpecker attacks, and percentage of phloem surface area covered by galleries was recorded. On 21 November and 2 December 2005, another four white ash and four blue ash trees in the Superior Township woodlot were felled and inspected using methods from the
September 2007
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