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杉木幼苗盆栽试验表明，杉木逢栽0～20cm表层土，盆栽杉苗成活率只有24.4％，生长量比同层头栽土下降41.8％．经连栽与头栽造林试验，结果表明连栽林地杉木保存率比头栽下降13．2％，连栽杉木当年幼树高仅21．6cm，6年生树高也仅214．9cm，而头栽杉木当年、6年生树高分别达37．4cm和367．0cm．采用回心土造林，连栽杉木保存率提高16.8％，树高生长量提高37．9％～60.2％；营造1．53hm2回心土示范林，成活率和生长量均显著高于常规造林.研究认为，不利于杉木连栽生长的限制因子集中在0～20cm表土层，是导致杉木连栽成活率和生长量下降的一个重要因素．
Cunninghamia lanceolata seedlings pot experiments showed that Cunninghamia lanceolata planted 0 ~ 20cm top soil, potted seedlings only 24.4% survival rate, growth of 41.8% lower than the same layer of top soil. The results of continuous planting and head plantation showed that the preservation rate of Chinese fir in continuous plantation decreased by 13.2% compared with that of the first plantation, and the height of the young plantation even in the year of planting Chinese fir was only 21.6cm. The tree height of the 6-year-old tree was only 214.9cm, Year of Chinese fir, 6-year-old tree height respectively 37.4cm and 367.0cm. With the help of soil reforestation, even the preservation rate of Chinese fir was increased by 16.8% and the growth of tree height was increased by 37.9% -60.2%. The 1.53hm2 rehabilitated forest was found to have a higher survival rate and growth rate than conventional reforestation. The study suggests that the limiting factors that are detrimental to the continuous plantation growth of Cunninghamia lanceolata are concentrated in the 0-20 cm topsoil, which is an important factor that leads to the decrease of the survival rate and the growth of continuous plantation.