Effect of planting techniques on the growth of Cunninghamia lanceolata(Lamb.) Hook plantations in Quang Ninh province

Abstract

The results of study planting techniques of Cunninghamia lanceolata
(Lamb.) Hook in Quang Ninh province after 39 months shows that
Cunninghamia lanceolatain the plantation experiments had the growth of
diameter above the crown (D00) from 2.4 cm to 4.9 cm, the mean of growth
stem height (H) from 1.8 m to 3.1 m, and the mean of canopy diameter (Dt
)
from 0.9 m to 2 m. In land preparation techniques experiments, the growth
of D00was measured from 3.4 cm to 4.1 cm, the highest (4.1 cm) at D4
treatment of hole size (60 60 60 cm) was recorded, the growth of H in
those experiments was from 2.1 m to 2.5 m. Seedlings age experime obtained D00was from 3.1 cm to 3.3 cm, the highest D00was 3.3 cm at TC2
treatment (12 - months-old seedling), and TC3 treatment (15 - months-old
seedling). The height of tree seedlings age experiments recorded from 2.0
m to 2.1 m. D00in planting density experiment was recorded from 3.3 cm to
4.9 cm, and H was from 2.3 m to 3.1 m. The highest D00 (4.9 cm) and
highest H (3.1 m) at a planting density of 3,300 trees ha
-1
were recorded. In
the fertilization experiments, D00of tree observed was from 2.8 cm to 3.7
cm, and H from 1.8 m to 2.1 m. The highest mean of D00 (3.7 cm) and the
highest mean stem height (2.1 m) was found in P4 treatment of applying
110gram urea + 350gram super phosphate + 50gram potassium. In pruning
experiments, D00oscillated from 2.4 cm to 2.9 cm, and stem height fluctuated
from 1.6 m to 2.9 m. The highest D00 (2.9 cm) and the highest H (1.8 m) were
found in C3 treatment (pruning from base to 30% height of the tree).