不同生境、造林模式闽楠人工林生长及林分分化

Growth and Structure Differentiation of Phoebe bournei Plantation with Different Sites and Modes of Afforestation

利用福建省三明市和建瓯市不同生境、造林模式闽楠人工林的24块代表性样地材料,对其生长及林分分化进行系统研究。结果表明:45龄闽楠人工纯林北坡、东坡林分树高均值明显高于西坡、南坡,而南坡、东坡林分平均胸径显著较北坡、西坡大,中坡、下坡生长明显优于上坡;45龄不同混交类型闽楠人工林中,与杉木混交效果较好,显著优于分别与福建柏、毛竹、木荷混交的林分;8 10龄弱光环境下闽楠林分在马尾松冠下和杉萌套种模式时生长较好,其树高、胸径显著大于杉木冠下闽楠林分;相同坡向、坡位、混交林及马尾松冠下闽楠人工林树高、胸径变异较小,而冠幅变异较大。不同微环境和造林模式的闽楠人工林径阶分布采用Weibull分布函数拟合,效果较好,各坡向、坡位闽楠人工纯林、与毛竹混交的林分及弱光条件下闽楠幼林均为倒"J"型分布,即其林分结构相对稳定、竞争较合理,而分别与杉木、福建柏和木荷混交的林分径阶呈单峰左偏山状分布,表明其处于竞争的自然稀疏后期;不同生境、造林模式闽楠林分林木分级显示,除杉萌套种和杉木冠下林分各级林木所占比例相对分散外,其他调查林分Ⅱ级木、Ⅲ级木占主导地位。因此,营建闽楠人工林应依据不同培育目标进行立地、混交模式及微环境选择,其人工林分宜选偏阳、半阳坡、中下坡,造林时尽可能选庇荫微环境,至中龄期可逐步移除冠层树种;杉木为其较理想伴生树种,与杉木混交林分的生长后期或杉萌套种闽楠林分郁闭期,建议间伐伴生树种;而弱光微环境应首选立地较好的马尾松冠下。

Based on 24 sample plots with different biotopes and afforestation modes in Sanming and Jian＇ ou of Fu- jian Province, the growth and stand differentiation of Phoebe bournei were analyzed. The results indicated that： for 45-year-old Phoebe bournei pure plantation, the height displayed conversely with the diameter at breast height （DBH）, the average height of Phoebe bournei grown at north and east slope was taller than that at south and west slope; however, the average DBH of stand at south and east slope was significantly larger than that of plantation at north and west slope; while the growth of the plantation at middle and lower slope was better than that at upper slope. For 45-year-old mixed plantation, the plantation mixed with Cunninghamia lanceolata was superior than that of other mixed modes such as mixed with Fokienia hodginsii, Phyllostaehys edulis and Schima superba. Likewise,the 8 to 10-years-old Phoebe bournei plantation grown under different shady environment displayed that young stand planted under Pinus massoniana crown and interplanted with coppice shoot of fir did better than that of under C. lanceolata. Not only the height of Phoebe bournei with the two modes mentioned above, but also the DBH of them were larger than that of under C. lanceolata mode. The variation of height and DBH of Phoebe bournei plantation in same direction and position of slope, mixed plantation and the under Pinus massoniana crown mode were small, oppositely, differentiation in crown of that was large. The model fitting diameter distribution for different microsites （slope, position of slope） and mixed modes of Phoebe bournei plantation with cumulative distribution function of Weibull distribution were good; The diameter distribution for plantation in different direction and position of slope, mixed plantation with Phyllostachys edulis and that planted under shady environment were the reverse ＂ J＂ type which means the stands had been undergoing stable stand structure and reasonable competition and the adaptability of this tree species strong. However, the diameter distribution for plantation mixed with C. lanceolata, F. hodginsii and S. superba took single hump with left avertence shape which indicated that the stands were in the late stage of natural thinning of competition period. And the tree species in class Ⅱ and Ⅲ were dominant in the stands except- ing the plantation grown with coppice shoot of fir and under C. lanceolata according to tree classification. Thus, it is necessary to select the microsite and mixed mode for Phoebe bournei plantation depending on cultivation target. For example, the pure plantation should be in partial sunny, half shady, middle and lower slope. Phoebe bournei plantation should be planted under shady environment and the crown tree species could be removed when the target plantations reach its middle stage. C. lanceolata is a better choice for Phoebe bournei. While, it is better to remove the associated species in Phoebe bournei plantations mixed with C. fir when they reach to closure period. If possible, it should choose ted under shady environment and fertility site. lanceolata and interplanted with coppice shoot of under Pinus massoniana crown mode when planted under shady environment and fertility site.