退化红壤区笋用小径竹幼林结构的变化规律

以红壤丘陵地植被恢复、生态环境改善和生产潜力发挥为目标,以优质笋用小径竹红壳竹Phyllostachys iridescens、早园竹Phyllostachys propinqua为对象,历时5 a定位研究竹子幼林结构主要因子的年际变化规律.结果表明:红壳竹和早园竹抽鞭发笋能力强,成竹率高,年际立竹量变化明显,以造林后第2年增加最为显著,可分别达到2 430株*hm-2和2 970株*hm-2,第3年成林投产.新竹平均胸径造林后第3年分别为3.54 cm和3.21 cm.第5年立竹量和立竹径级达到丰产林分结构水平.红壳竹和早园竹地下鞭系多分布于土壤上层20 cm区间,造林后第3年鞭系长度达10 m*m-2以上,平均鞭径分别为1.75 cm和1.32 cm,鞭系径级均匀度提高.单位面积林地鞭系侧芽数随着造林年限的增加显著增多,造林后第3年分别是第1年的119.4%和202.9%.指出2竹种在红壤丘陵地适应性好,可规模化推广应用.造林母竹标准为2.5～3.5 cm径级的1～2年生健康立竹,初植密度900～1 500株*hm-2.加强幼林期土壤管理和竹林结构调控是早成林和良好经济性状表现的主要措施.表6参12

Circannual rhythm of young stands structure of Phyllostachys iridescens and Phyllostachys propinqua in red soil area

Aimed at vegetation resume and entironment improve, exert potential of production in red soil area ,and objected to Phyllostachys iridescens and Phyllostachys propinqua. Through five years orientation study on the changing rule of young bamboo stands structure. The results showed that the ability of scourging and sprouting of Phyllostachys iridescens and Phyllostachys propinqua are strong, the ratio of new bamboo stand culms is highness, the changing of bamboo stand culms year by year is notability, reach to respectively 2 430 and 2 970 individual plants each hectare second year, and put into production third year after forestation. Average diameter in breast height(DBH) of new culm reach to 3.54 cm and 3.21 cm respectively at third year after forestation. Bamboo stand culms and DBH reach to level of fertility at fifth year after forestation. Bamboo rhizome of the two species mainly distributing the range of above 20 cm thick soil, length of rhizome exceed 10 m per spuare meter third year after forestation, and average diameter of rhizome are 1.75 cm and 1.32 cm respectively, amount of sprout is increasing along with forestation years, third year up to 119.4% and 202.9% than first year after forestation. The paper indicated the two bamboo species can be extend at large scale in red soil with characteristics of strong eco-adaptability and good economic profit. Standard seedling is one and two year age with 2.5 cm and 3.5 cm DBH, and first forestation density is 900 and 1 500 individual plants each heatare. Soil management and bamboo stands structure adjustment are mainly measures to young bamboo stands for ahead of put into production and higher profit.Ch,6 tab.12 ref.]