桂西南不同树种人工林评价研究

对桂西南多个树种、多种经营模式人工林的生长量、林下土壤及植被的调查研究和经济效益分析表明:米老排、红椎、西南桦等速生阔叶树种的生长量优于针叶树种,其中,胸径、树高年平均生长量以米老排为最高,分别达1.67 cm、1.29 m,分别比马尾松增长60.6%、61.2%,比杉木增长70.4%、57.3%;林分的年平均蓄积生长量则以西南桦为最高,达20.44 m3·hm-2·a-1,比杉木高了近2倍.阔叶林的经济效益明显优于针叶林,混交林的效益优于针叶纯林,树种之间效益比较达显著或极显著差异,其中以西南桦的效益最好,年平均产值达21 459.7元·hm-2,比杉木高10倍多.对土壤理化性质的研究表明:荒地造林后,土壤的密度、保水性、通透性得到改良;土壤有机质含量提高,富铝化作用增强,而其它的土壤养分,不同树种之间差异较大,但从总体看,阔叶林在改良土壤理化性质方面优于针叶纯林.

Evaluation of Tree Species of Plantation in Southwest Guangxi

The results of investigation and economic benefits analysis on increments,forest soil and vegetation of plantations with multiple tree species and under various management patterns showed that the increments of fast-growing broadleaved tree species such as Mytilaria laosensis,Castanopsis hystrix,Betula alnoides,etc.were higher that of coniferous species.Mytilaria laosensis had the highest annual average dbh and height increments,which were 1.67 cm,1.29 m respectively,60.6% and 61.2% higher compared with Pinus massoniana,70.4% and 57.3% higher compared with Cunninghamia lanceolata.Betula alnoides had the highest annual average stock volume increment(20.44 m³·hm^-2),which was near double compared with that of Cunninghamia lanceolata.The economic benefits of broadleaved forest were obviously higher than that thet of coniferous forest,while that of mixed forest was higher than that of pure coniferous forest.There existed obvious of extreme obvious difference in economic benefits among tree species.Betula alnoides had the highest benefits with the annual average value of 21 459.7 RMB yuan per hectare,ten times that of Cunninghamia lanceolata.The study on soil physical and chemical properties showed that after afforestation,the soil bulk density,water-holding capacity and water permeability improved,the soil organic matter content raised and aluminum-enrichment ability was promoted.For other soil nutrients,there existed significant difference among tree species,but overall,the broadleaved forest was better than coniferous forest in improving soil physical and chemical properties.