Abstract:

In order to scientifically manage Juglans mandshurica， combined with its crown width reflecting growing space, the relationship between growing space and individual, stock volume periodic increment of 5, 10 and 15 years’ interval for bringing up Juglans mandshurica in second growth forests of Changbai Mountains was studied based on the 34 analytical trees (DBH 11.0～39.1 cm) growing in canopy layer. Regression models of optimal growing space in different upbringing intervals to DBH were constructed. Based on analytical data from 27 trees (DBH 4.6～14.3 cm) growing in understory, optimal growing space models for growing trees in understory were established to evaluate nurturing effects. The 3-parameter sigmoid models and quadratic models were able to well describe the relationship between individual, stand periodic volume increment to crown width of Juglans mandshurica, respectively. The power models could significantly describe the relationship between optimal growing space in different upbringing intervals to DBH of Juglans mandshurica. The logarithm models could significantly describe the relationship between periodic volume increment to DBH of Juglans mandshurica growing in optimal growing space. The periodic volume increments of J. mandshuria in 5, 10 and 15 years′interval growing in optimal growing space at least increased 97.8%, 114.4% and 128.5%, respectively compared with the suppressed space. The ratioes of optimal growing space (m) for bringing up Juglans mandshurica in 5, 10 and 15 years’ interval to DBH (cm) was 0.256 6～0.368 7, 0.344 1～0.447 1, and 0.449　1～0.504 6, respectively.

Key words: second growth forest, Juglans mandshurica, crown width, optimal growing space