| Measuring drought and drought impacts in Red Sea Province |
|8. Changes in tree density on five sites in Red Sea Province: early 1960s to 1989. Roy Cole|
The Khor Akwaat sites
The Khor Akwaat sites are situated in middle Khor Akwaat above Sallum Station 30 kilometres southwest of Port Sudan in Rural Port Sudan District. For each site in Khor Akwaat we selected an area 1000 meters square. From each of these areas we selected three strips parallel to the Khor each 100 meters wide and 1000 meters long in which the trees were to be counted. The first, fourth and ninth strips were chosen to be measured; one strip on the edge, one in the middle and on the end of each block. At the Akwaat site the east-west dimensions of the study areas were found by measuring the distance of the telegraph poles along the railway. A Landrover was used to measure the north-south dimension. The map located on the following page shows the Khor Akwaat study area.
The Khor Oko site
The Khor Oko study site is located 170 kilometres west-northwest of Port Sudan on the western side of the Red Sea hills in Halaib District. This remote area is one of the driest in the region. Practically all vegetation is confined to khor beds and water lines. Because of the relatively low density of vegetation and its homogeneity along Khor Oko, a 500 square meter block was chosen randomly from the aerial photographs of the vegetated course of Khor Oko. A 1:250000 false-colour Landsat image was used to locate the study site in the difficult terrain and the 1:40000 photograph of the study area was used to define the location of the site more precisely. The dimensions of this site were measured with ropes 500 meters in length. The map on the following page shows the Khor Oko study area.
The Khor Sitareb site
The Khor Sitareb study site is located on the eastern side of the khor on a minor tributary near the source of Khor Sitareb. This site is 140 kilometres south-southwest from Port Sudan in North Tokar District. A strip 500 meters long and 100 meters wide was chosen from the 1:40000 photographs as the Sitareb study site. The site is located along the east bank of the tributary and extends 500 meters to the west. The 500 meter long strip was divided into 5 onehectare squares using ropes and the trees were counted on a hectare by hectare basis. Map 8.4 on the next page illustrates the situation of this site.
The Khor Nubahawayb site
This site is located on a minor tributary of Khor Nubahawayb. It is located 115 kilometres west-southwest of Port Sudan in Rural Port Sudan District. A study area of 2 hectares was chosen from this minor khor, transecting it at the point just before it leaves the mountains to join sandy Khor Nubahawayb and the sandy 'Udrus basin. The map on the following page presents the site in detail.