The Coppices of Ziziphus Spina Christi (L.) Willd.

Growth in length and Stems Diameters Accumulation Growth in Spate Irrigated Areas at Wadi Shohouh-Hadhramout

Abstract

Wadi Shohouh is linked with southern plateau of main Wadi Hadhramaut. Areas of 25000 ha in the valley
are irrigated by spate irrigation system where rainfall may exceed 150 mm annually but it may reach 50
mm less in other year. Ziziphus ( Seder ) trees are distributed on a simple sloping terraces basins varied
between 6000 -14580 m². After felling Seder trees, ten of regenerated trees from each farm had been
selected randomly. Seder trees had been left for five years under traditional management farming system
and at the end of each year, tree’s coppices are counted and measured for height and stems diameters.
This study showed that the height growth of coppice is fast and high in the first year. The mean growth
may mostly reach above 3 m while in the same year stem diameter growth is also fast and high and mean
growth may reach more than 1.0 cm. On other hand current annual growth increment of diameter varied
between 0.550 – 0.752cm. High standard deviation for height is varied between ± 0.642 – ± 1.890 m,
whereas coefficient variation is also high in general. High standard deviation for coppice stem diameter
growth reached ± 0.542 – ± 1.474 cm while coefficient variation is high in general as well. Data on
annual growth diameters accumulation in this experiment revealed significant differences at 5% level.
Significant differences were found between some years and between some others are non. High mean
growth diameters accumulation occurs in first, second and third years ( 64.2, 63.2 & 62.0 cm )
respectively. At the same level of significance there are significant differences for diameters growth
accumulation between some locations and non between others and high mean diameters growth
accumulation was reached in first location as ( 74.6 cm) .