马尾松不同林龄林分生物量与净生产力研究

Study on Biomass and Net Productivity of Pinus massoniana of Stand at Different Forest Ages

2010年,对贵州省独山县国有林场马尾松人工林幼龄林(七年生)、中龄林(十四年生)和成熟林(三十年生)林分的生物量与净生产力进行了测量研究。结果表明,3种林龄林分生物量分别为19.11、54.68、108.26 t/hm2,幼龄林和成熟林各层次生物量的高低排序都为乔木层、枯落物层、草本层、灌木层,中龄林各层次生物量的高低排序为乔木层、枯落物层、灌木层、草本层。乔木层生物量占林分生物量的43.49%～93.70%,并随着林龄的增加不断提高;而灌木层、草本层和枯落物层则与乔木层相反,生物量所占的比例随着林龄的增加有所下降;不同林龄马尾松林林分中乔木层生物量占有绝对的优势。在不同林龄单株生物量方面,幼龄林单株生物量的高低排序为树干、枝条、针叶、根系,而中龄林、成熟林单株生物量的高低排序都为树干、根系、枝条、针叶,且均以树干生物量所占比例最大,占整株生物量的52.00%～72.46%。在净生产力方面,3个林龄的林分净生产力以中龄林最高,达到10.949 5 t/(hm2.a);其次是成熟林,为9.1526 t/(hm2.a);幼龄林排后,为8.566 4 t/(hm2.a);乔木层净生产力也是中龄林最高,达到5.479 5 t/(hm2.a),大于成熟林的5.040 1 t/(hm2.a)和幼龄林的1.941 4 t/(hm2.a)。该林场马尾松林林分生物量和净生产力相比较而言在国内处于低水平,因此应加强林场马尾松林的经营管理,采取有效措施实施林分结构和密度调整,加大林相改造力度,从而提高林分生产力及群落整体生态效益。

In 2010,the biomass and net productivity of young forest（7-year-old）,medium-aged forest（14-year-old） and mature forest（30-year-old） of Pinus massoniana Lamb.plantation in state-owned forest farm forest of Dushan county,Guizhou province were measured and analyzed.The results showed that the stand biomass of forests with different age was 19.11,54.68,108.26 t / hm2 respectively.The rank of biomass of different layers in young and mature forests from high to low was tree layer,litter layer,herbaceous layer and shrub layer,while in middle-aged forest was tree layer,litter layer,shrub layer and herbaceous layer.The biomass of tree layer accounted for 43.49%～93.70% of forest biomass,and increased with forest age.While the biomass of shrub layer,herbaceous layer and litter layer decreased with the increase of forest age.Biomass of tree layer dominated in P.massoniana forest with different ages.In terms of single plant biomass,the sort of biomass of plant in young forest from high to low was trunk,branch,needle,root,in middle-aged forest and mature forest was trunk,root,branch and needle;and the trunk accounted for the largest proportion of whole plant biomass,52.00% ～72.46%.In terms of net productivity,medium-aged forest was the highest,10.949 5 t /（hm2.a）;followed by mature forest,9.152 6 t /（hm2.a）;young forest was the lowest,8.566 4 t /（hm2.a）.The net productivity of tree layer in medium-aged forest was the highest,5.479 5 t /（hm2.a）,greater than that in mature forest 5.040 1 t /（hm2.a） and young forest 1.941 4 t /（hm2.a）.The biomass and net productivity in the studied P.massoniana forest was at low level.The forest management should be strengthened;and effective measures should be conducted to adjust the stand structure and density and improve the forest form,thereby increasing forest productivity and community ecological effects.