Ash dieback mortality and damage at the Botanic Garden Meise, Belgium

Four 10m × 10m plots were laid out in the naturally regenerating woodland at the Botanic Garden Meise (WGS84: 50° 55ʹ 37ʺ N, 4° 19ʹ 18ʺ E; 50° 55ʹ 37ʺ N, 4° 19ʹ 17ʺ E; 50° 55' 38.6" N 4° 19ʹ 21ʺ E; 50° 55ʹ 39ʺ N, 4° 19ʹ 29ʺ E). They were selected because the areas contained a large number of ash saplings. Within these plots all ash seedlings greater than 40 cm tall were labelled with a small (2 cm × 4 cm) plastic tag attached with stretchable plant tie. Each tag was engraved with a unique number so that the tree could be identified. These plots were not intended to be replicates but just a convenient method of refinding the tagged trees. In the first year either the height or the girth of the tree was measured with a tape measure, depending upon whether the tree was small enough to measure the height. In the first year and each subsequent year each tree was scored for the apparent damage caused by ash dieback (Hymenoscyphus pseudoalbidus). The same scoring scheme was used as that by Pliūra et al. (2011). This is a 5 point system where 1 is a dead tree; 5 is an undamaged tree and 2–4 are progressively less damaged trees. The plots were laid out on 14 April 2013. In 2014 plots 1 and 2 were scored on 14th April  and plots 3 and 4 on 21st April. In 2015 plots 1 and 2 were scored on 6th May and plots 3 and 4 on 30th April.