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Growth process and
diameter structure of Pinus tabulaeformis forest for
soil and water conservation in the hilly loess region of
China
J. B. Xia1, G.
C. Zhang3*, S. Y. Zhang5 and H. B. Shao2,4,6*
1Shandong
Key Laboratory of Eco-Environmental Science for Yellow River
Delta,
Binzhou University, Binzhou 256603, China.
2State
Key Laboratory of Soil Erosion and Dryland Farming on the
Loess Plateau, Institute of Soil and Water Conservation,
Chinese Academy of Sciences, Yangling 712100, China.
3Key
Laboratory of Agricultural Ecology and Environment, Forestry
College, Shandong Agricultural University, Taian 271018,
China.
4Yantai
Institute of Costal Zone Research for Sustainable
Development, Chinese Academy of Sciences, Yantai 264003,
China.
5Resources
and Environmental Sciences College, Northeast Agricultural
University, Harbin 150030, China.
6Institute
of Life Sciences, Qingdao University of Science and
Technology, Qingdao 266042, China.
*Corresponding authors. E-mail:
shaohongbochu@126.com
(Hong-Bo) and
zhgc@sdau.edu.cn (Guang-Can); Tel.: 86-532-84023984.
Accepted
7 July, 2009 |
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Using stem analysis method, the biomass, growing process and
diameter structure of
21-year
shady and sunny slope Pinus tabulaeformis forest
were investigated
in hilly loess-gully region. Results showed that there were
distinct difference in the indexes, tree height, diameter at
breast height (DBH) and timber volume between shady and
sunny slope forest. The biomass, growth status and its
diameter structure of shady slope forest were greater than
those in sunny slope forest. The fast-growing period of tree
was from 9 to 13 years. After 13 years, the annual increment
of shady slope forest was greater than that of the sunny
slope forest (the annual increment of shady slope forest
reached 0.26 m•a-1, while it was about 0.1 m•a-1
in sunny slope forest in the 21st year).The DBH growth
increment of 2 forests were reduced greatly after 13 years,
but the declining degree of shady slope forest was less than
the sunny slope forest. The current annual increment of
shady slope forest was greater than the sunny slope forest
after 17 years. There was little difference in the increment
of 2 timber production before 13 years. But the increment of
shady forest was greater than the sunny forest after 13
years (in the 21st year, the annual increment was 0.0023 m3
in shady slope, but in sunny slope it was only 0.0015 m3).
The summit of DBH distribution curve was both partial to
left, while the skewness (SK was 0.75) of shady forest was
lower than that of the sunny forest (SK was 1.03) and
kurtosis (K was 1.05) of shady forest was higher than that
of sunny forest (K was 0.94). The results indicated the
density structure of sunny slope forest was greater than
shady slope forest.
Key
words:
Hilly loess region, Pinus tabulaeformis forest,
forest increment, diameter structure. |
