Abstract:

Morphological characters of tree rings of Sabina vulgaris grown in Mu Us Sandland were observed using entitative microscope and optical microscope. Moreover, by means of stem analysis, the growth dynamic both in radial and longitudinal direction were studied for S. vulgaris grown both in lowland and on the top of dune. The results showed that eccentric growth of S. vulgaris on the top of dune was obvious with a ratio of 140.36% (long diameter to short diameter). The false ring occurred at a frequency of 12.07 %. However, the eccentric growth of that grown in the lowland was not obvious with a ratio of 105.22% and the false ring occurred at a frequency of 1.80%. According to the ring, S. vulgaris on the top and lowland of dune existted more than 123 and 50 years respectively. For S. vulgaris grown on the top of the dune, the annual radial growth was only 0.94 mm and had no obvious peak value in the whole annual radial growth. The shape “S" in the cumulative growth curve was not notable. For S. vulgaris grown in the lowland of dune, the peak annual radial growth occurred in the 35^th ring, the annual mean radial growth was 1.51 mm, 1.6 times as much as that on the top of dune. The shape “S" in cumulative growth curve was neither notable. The length and the age of stolon of S. vulgaris on the top of dune showed an exponential correlation, while that in lowland showed a significant linear correlation.

Key words: Mu Us Sandland, Sabina vulgaris, growth dynamic of tree rings