5种北美栎树在我国长三角地区的引种生长表现

从美国东南部引进属于红栎组的纳塔栎、舒玛栎、水栎、柳叶栎和属于白栎组的弗栎,在我国长江三角洲平原地区多个地点和不同土壤类型条件下进行造林研究.采用1～2年生裸根苗经长途运输后进行栽种,纳塔栎、舒玛栎和水栎成活率达94％以上,柳叶栎为76％～81％,弗栎仅42％～50％.不同树种之间,幼年阶段的根系发育、枝梢生长习性、秋冬叶色变化和虫害状况存在明显差异.在3～6个地点水稻土上建立的前4种栎树人工林,8～10a后在保留密度900～1 500株·hm-2条件下,其年均径生长量和年均高生长量达到0.96～1.76 cm和0.8～1.33 m.在山坡红黄壤地上栽种的纳塔栎、舒玛栎和柳叶栎,其年均径生长量和年均高生长量分别为0.64～1.01cm和0.57～0.78 m.采用2～4年生带土弗栎苗在6个地点滨海盐土上造林的成活率达87％以上,在保留密度1 110～3 900株·hm-2条件下,其7～9 a林木年均径生长量和年均高生长量分别为0.78～1.13 cm和0.59～0.75 m.当树龄达6～9 a时,5种栎树均开始结实.研究表明,5种北美栎树在长江三角洲地区有较强的适应性,水栎、纳塔栎、舒玛栎、柳叶栎可以应用于平原地区生态景观林和城镇园林绿化建设,而弗栎在沿海防护林建设中具有推广前景.

Growth Performances of Five North Ameirican Oak Species in Yangzi River Delta Of China

Four red oak species including Nuttall oak (Quercus nuttallii), Shumard oak (Q. shumardii), Water oak (Q. nigra), Willow oak (Q. phellos) and one white oak species, Live oak (Q. virginiana) from Southern USA were introduced for establishing plantations at different sites and soil types in Yangtze River Delta of China. When 1-or 2-year-old bare-root seedlings were planted after a long distance of transportation, the survival rates of Nuttall oak, Shumard oak, and Water oak were higher than 94%, while the survival rates of Willow oak and Live oak were 76% 81% and 42% 50% respectively. Obvious differences existed among species in root and shoot growth habits, phenology and pest occurrence at young stage. For the four red oak plantations established on paddy soil, the mean annual DBH increments and height increments after 8 10 years ranged from 0.96 to 1.76 cm and 0.8 to 1.33 m with the reserved density of 900 1 500 trees per hectare. But the mean annual DBH increments and height increments of stands on hill with red-yellow soil ranged from 0.64 to 1.01cm and 0.57 to 0.78m, respectively. The Live oak stands planted with 2-to 4-year-old seedlings with clod-ball on coastal saline soil had a survival rate of higher than 87%, and the mean annual DBH increments and height increments at the age of 7 9 were 0.78 1.13 cm and 0.59 0.75 m respectively with the density of 1 110 3 900 trees per hectare. All the trees of the 5 oak species begun to bear fruit at the age of 6 9. The research showed that the 5 oak species had good adaptability to natural conditions in Yangtze River Delta. Water oak, Nuttall oak, Shumard oak and Willow oak can be applied for construction of plain landscapes and ecological stands, and Live oak has broad prospects for coastal protective forest.