Effect of Initial Planting Spacing on the Growth of Betula alnoides

A spacing trial for Betula alnoides was established in Daqingshan, Guangxi. The results showed that spacing has no considerable impact on height growth while remarkably negative impact on diameter growth. The difference of mean DBH between 3 m×3 m and 1.5 m×2.0 m is 2.88 cm. The growth increment of tree with spacing 3 m × 3 m is 32.3% higher than that with the spacing 1.5 m×2.0 m, 28.4% of 2 m×2 m, and 11.6% of 2 m×3 m. The volume increment of single tree was negatively correlated to the planting spacing which followed the formula of ax-b. The stock volume was positively correlated to planting spacing. The stock volume of these four planting spacing tend to be of less difference with time going.