Some variation in Acacia Seyal Del. variety Seyal (BRENAN) in Sudan, in relation to the colour of the bark

Acacia seyal var. seyal is characterized by various colours of the bark which range frome red, blend and green. Four forest sites were selected to study variation in this coloration of the bark. These are Okalma forest (Blue Nile State), El Rawashda forest (Eastern State), Um Fakarein forest (South Kordofan State) and Ed El Heglieg forest (North Kordofan State). Fifteen trees were randomly selected from each colour within each site. Morphometric data was taken for each tree within each site. It includes leaf, inflorescence and fruit parameters, wich were analyzed statisticlly using ANOVA followed by Duncan's multiple range test for mean separation. It was found that the colour of the bark over all or within each site has a significant association with head diameter and floret number per head (P0.005 P0.0001), respectively, but the bark colour did not show significant relationship with leaf and fruit parameters. The site location, on the other hand, is highly significantly associated with leaf, inflorescence and fruit parameters. One year old seedlings of approximately simlar size and density with red and green-bark were subjected to different irrigation regimes of 2-days, 7-days and 14-days inervals. It was found that, there was a significant difference in growth rate of both coloured-bark seedlings with prolonged irrigation interval. However, the rate of growth of the green-bark seedlings was significantly greater than that of the red-bark ones, and the difference in growth of the letter was twice that in the former ones. Sections of juvenile and mature wood were prepared for wach coloured-bark tree. Anatomical structures were compared. It was found that structurally wood of the red, blend and green-bark tree were similar. However, they were different only in the deposition of secondary materials which might be tannins, gum, and starch and calcium oxalate crystals. The green-bark trees had a great amount of deposits followed by the blend-barked, while the red barked ones had the least deosits. Morecover, the section through the bark of each coloured-bark tree showed that, the bark layers varied from each other in the width of the external layer and the density of deposition, the green-bark tree being superior