Monday, 17 November 2003
The Phenology and Natural Regeneration of Two Native Pine Species in Subtropical Forest Burned Areas of Central Taiwan
Fire is one of the major disturbances in subtropical forests in the central Taiwan. The phenology and natural regeneration of two native pines, Pinus taiwanensis and P. morrisonicola, were investigated in the burned areas at the Guandaushi Forest in the central Taiwan. We hypothesized that P. taiwanensis would be more successful in burned areas because of its semi-serotinous cones. Some mature cones of P. taiwanensis remained sealed for up to six months, but cones of P. morrisonicola opened once matured. Semi-serotinous cones exist in P. taiwanensis; however, cones of P. morrisonicola are nonserotinous and release seeds immediately after maturity. The maximum seed fall of P. taiwanensis and P. morrisonicola in burned areas was 17.95 and 7.22 seed/m2/month, respectively. However, the percentage of viable seeds was only 33.3% in P. taiwanensis and 75.0% in P. morrisonicola. The survival and development of seedlings were affected by soil water content and vegetation competition. Density of P. taiwanensis seedlings in burned areas declined from 0.74/m2 in the first year after fire to 0.29/m2 four years after fire, but the density of P. morrisonicola was less than 0.01/m2 in both one year and four years after fire. The P. taiwanensis seedling establishment in the burned areas was more successful than P. morrisonicola, and our hypothesis about relative success of the pine species was confirmed.