Spatial Distribution and Structural Characteristics for Haloxylon ammodendron Plantation on the Southwestern Edge of the Gurbantünggüt Desert

Haloxylon ammodendron (C.A.Mey.) Bge. is crucially important for stabilizing sand dunes in the desert area of Junggar Basin and has thus been widely planted oasis–desert ecotone windbreak fixation purposes since 1980s. The spatial distribution structural characteristics plantations three different ages—planted 1983 (36a), 1997 (22a), 2004 (15a)—on southwestern edge Gurbantünggüt Desert were studied. results showed that patterns stages growth a trend cluster was random during transformation from seedlings to juvenile mature trees. Forest density 15a, 22a, 36a was, respectively, 1110, 1189, 1933 plants ha?1; base stem diameter main forest layer 5.85, 8.77, 6.17 cm, tree height concentrated range 1.5–3.0 m, 2.0–3.5 1.5–2.5 m. In regeneration layers, proportion largest all stand ages, followed by trees, trees only appeared 22a plantation. deadwood highest, there no layer. These indicate plantation period rising at stable degenerate with increasing age ability very weak presented degradation due species competition soil moisture, because too many plants. this case, measures such as thinning could be taken prevent rapid accelerate when exceeds 20 years. Considering effect, pressure water resources, capacity renewal sustainability, most suitable would 8.5–9 m2 per plant.