对木麻黄基干林带分别采用不同采伐带宽度带状更新,不同树种和造林密度带状更新,多树种混交配置和林下套种更新,结果表明:10、20及30 m 采伐带宽度更新木麻黄无性系粤_(601),生长差异不显著,受风害程度随采伐带宽度增大而加剧;以木麻黄粤_(601)无性系、刚果12号桉、湿地松3个树种和品系采用挖大穴、下客土、雨天造林等技术对基干林带更新(带宽20 m),更新树种保存率高、生长量大;湿地松不同密度对基干林带更新(带度10 m),在造林初期密度效应不明显,不同密度生长差异主要由小环境造成;木麻黄、厚荚相思、刚果12号桉、湿地松等树种多行配置对林带更新形成合理的多层次结构,木麻黄主林层,厚荚相思、刚果12号桉亚林层,湿地松处于第三层次,这种结构既有利于防风,又达到改良土壤和改善林带气候条件目的。湿地松与厚荚相思、刚果12号桉单行混交受压严重;林下套种树种生长量随基干林带郁闭度增大而下降,郁闭度0.3以下的基干林带套种相思树、刚果12号桉、湿地松、木麻黄等树种保存率高、生长潜力大。
The soil respiration rates （Rh） in 6-year-old （young）, 17-year-old （middle-age）, 31-year-old （mature） Casuarina equisetifolia coastal plantations were measured using an LICOR-8100 automated soil CO2 flux system from May 2006 to April 2007. Results show that Rh displayed an obvious seasonal pattern across the observed years. The maximum values of Rh occurred at June and July and the minimum at December and January. Soil temperature and soil moisture as well as their interaction had significant effects on the monthly dynamics of Rh. The analysis by one-way ANOVA showed that Rh had a significantly exponential relation （p〈0.05） to soil temperature at soil depth of 5 cm, and had a linear relation （p〈0.05） to soil water content of the upper 20 cm. The result estimated by the two-factor model shows that soil temperature at soil depth of 5 cm and soil moisture at soil depth of 20 cm could explain 68.9%-91.9% of seasonal variations in Rh. The or- der of Rh rates between different stand ages was middle-age plantation〉mature plantation〉young-age plantation. With the increase of growth age of plantation, the Q10 of Rh increased. The contribution of Rh to total soil surface CO2 flux was 71.89%, 71.02% and 73.53% for the young, middle-age and mature plantation, respectively. It was estimated that the annual CO2 fluxes from Rh were 29.07, 38.964 and 30.530 t.ha^-1.a^-1 for the young, middle-age and mature plantation, respectively.
