无瓣海桑人工林的生物量与能量研究

Biomass and Energy Flow of Sonneratia apetala Community in Leizhou Peninsula,China

关键词:  红树林  无瓣海桑  生物量  能量

Key words:  Mangrove  Sonneratia apetala  biomass  energy

摘要:

了认识引进红树林树种无瓣海桑(Sonneratia apetala)的生长与生态特征,对雷州附城镇岚北无瓣海桑生态恢复林地进行样方调查与树干生长分析、凋落物收集网收集、干重热值实验分析和网袋就地凋落叶分解试验。结果表明:岚北7a生无瓣海桑群落平均单株无瓣海桑材积为101.415dm³;群落现存生物量为25.016kg/m²,地下部分现存生物量与地上部分现存生物量比例为0.32;当年现存生物量为8.154kg·m^-2·a^-1;2001年2月至2002年1月凋落物总量为1.895 kg·m^-2·a^-1;当年群落生产力为10.040kg/m²;群落能量现存量为443.483MJ/m²;单株能量固定量为1847.849MJ;当年能量固定量为144.132MJ/m²,当年年能量归还量34.152MJ·m^-2·a^-1(2001年),当年能量净固定量为179.474MJ·m^-2·a^-1,当年光能转化率为8.10%。同一季节的落叶分解速率相同,半分解期干冷季节为11d、湿热季节为7d,表现出较高的分解速率。无瓣海桑群落具有显著的高生物量与能量积累和归还量特性,其生产力水平处于我国红树林群落中的最高值,其对太阳能的利用形成生物量的水平接近该生态系统最适条件下的水平。因此,对裸滩宜林地选择无瓣海桑进行红树林生态恢复造林,具有成林快、景观和防护等生态效益明显的特点,适合的华南沿海滩涂推广。但是对红树林保护区而言,人工无瓣海桑群落的上述快速生长特性则表现为极强的入侵性,应引起各沿海红树林保护区高度重视和警惕。

Abstract:

Mangrove Sonneratia apetala has been introduced and planted in large areas of mudflats in South China in order to meet the ecological services.To probe into its growth and ecological characteristics,the plot survey,wood growth analysis of the standard trees,litter fall net collection,in-site decomposing experiments of litter-leaves in net bags and gross caloric value tests of dry samples in the restored mangrove S.apetala communities in Lanbei,Fuchen,Leizhou,were carried out.The results were as follows.In the seven-year old Lanbei community,average single wood volume was 101.415 dm³;stand biomass was 25.016 kg/m² with underground parts to aboveground parts ratio 0.32;current year stand biomass was 8.154 kg·m^-2·a^-1;annual litter fall was1.895 kg·m^-2·a^-1 during the period between Feb.2001 and Jan.2002; current year productivity was 10.040 kg/m²; stand energy fixed amount(EFA) was 443.483 MJ/m²;average single stand EFA was 1847.849 MJ;current year stand EFA was 144.132 MJ/m²;current year energy return amount was 34.152 MJ·m^-2·a^-1;current year net EFA was 179.474 MJ·m^-2·a^-1;solar energy fixed rate was 8.10%.The litter leaf decomposition trials revealed that the high decomposition rate of S.apetala litter leaves with half dry mass decomposed was 11 days in the dry-cold season and 7 days in the rain season.The biomass and energy data of the above parts showed that the S.apetala community was the highest in productivity among mangroves in China as indicated by the ratio of solar energy fixing efficiency which was close to its upmost ecosystem productivity level.Therefore,S.apetala is suggested to be planted in the open coastal mudflats of southern China in order to obtain faster forestation and better coastal sheltering and other ecological benefits.But for the national mangrove reserves,the strong ecological invasion of S.apetala communities should be watched out.