在25 a生马尾松林下分别套种1 a生火力楠、闽粤栲、苦槠、格氏栲、青栲和拉氏栲等阔叶树种的幼苗,16 a后形成郁闭的针阔混交异龄林.通过定位监测和化学分析,对上述6种混交林类型及林下未套种阔叶树的马尾松纯林的森林凋落量及养分通量...在25 a生马尾松林下分别套种1 a生火力楠、闽粤栲、苦槠、格氏栲、青栲和拉氏栲等阔叶树种的幼苗,16 a后形成郁闭的针阔混交异龄林.通过定位监测和化学分析,对上述6种混交林类型及林下未套种阔叶树的马尾松纯林的森林凋落量及养分通量进行了研究.统计结果显示,6个混交群落的年凋落量分别为7 137.3 kg hm-2、6 741.1 kghm-2、8 041.7 kg hm-2、7 151.3kg hm-2、7 533.2kg hm-2和6 149.1 kg hm-2,而马尾松纯林的年凋落量仅3 442.8 kghm-2.在所有林分的凋落物组成中,枯叶占绝对优势,占凋落物总量的49.7%～71.5%,其余依次为枯枝(5.7%～26.1%)、其它组分(5.5%～17.1%)、树皮(7.7%～18.9%)和果实(0.7%～2.0%).各混交林分中来自马尾松的凋落物占50.4%～58.0%,而来自阔叶树的凋落物占42.0%～49.6%,且两者的组成存在明显差异.各林分总凋落量的季节动态呈双峰型,第1次峰值出现在2～4月份,第2次峰值出现在8、9月份.凋落物中主要养分元素的含量依林分类型、凋落物组分和凋落时间不同而异,N、P、K、Ca和Mg的含量范围依次为3.25～12.98 g kg-1、0.23～0.97 g kg-1、0.42～4.02 g kg-1、7.34～32.57 g kg-1和1.34～5.58 g kg-1.不同的林分类型,凋落物中各养分元素的年通量大小均为:Ca＞N＞Mg＞K＞P.马尾松纯林中,通过凋落物的5种养分元素的年流通量为142.01 kg hm-2;而在林下分别套种上述6种阔叶树后,其养分年流通量依次增加到204.95 kg hm-1、223.93 kg hm-2、304.12 kg hm-2、288.46 kg hm-2、213.77 kg hm-2、238.05 kg hm-2.展开更多
Tropical forests play a critical role in mitigating climate change because they account for large amount o terrestrial carbon storage and productivity.However,there are many uncertainties associated with the estimatio...Tropical forests play a critical role in mitigating climate change because they account for large amount o terrestrial carbon storage and productivity.However,there are many uncertainties associated with the estimation o carbon dynamics.We estimated forest structure and carbon dynamics along a slope（17.3°–42.8°）and to assess the relations between forest structures,carbon dynamics,and slopes in an intact lowland mixed dipterocarp forest,in Kuala Belalong,Brunei Darussalam.Living biomass,basa area,stand density,crown properties,and tree family composition were measured for forest structure.Growth rate,litter production,and litter decomposition rates were also measured for carbon dynamics.The crown form index and the crown position index were used to assess crown properties,which we categorized into five stages,from very poor to perfect.The living biomass,basal area and stand density were 261.5–940.7 Mg ha-1,43.6–63.6 m2ha-1and 6,675–8400 tree ha-1,respectively.The average crown form and position index were 4,which means that the crown are mostly symmetrical and sufficiently exposed for photosynthesis.The mean biomass growth rate,litter production,litter decomposition rate were estimated as11.9,11.6 Mg ha-1a-1,and 7.2 g a-1,respectively.Biomass growth rate was significantly correlated with living biomass,basal area,and crown form.Crown form appeared to strongly influence living biomass,basal area and biomass growth rate in terms of light acquisition.However,basal area,stand density,crown properties,and biomass growth rate did not vary by slope or tree family composition.The results indicate that carbon accumulation by tree growth in an intact lowland mixed dipterocarp forest depends on crown properties.Absence of any effect of tree family composition on carbon accumulation suggests that the main driver of biomass accumulation in old-growth forests of Borneo is not species-specific characteristics of tree species.展开更多
文摘在25 a生马尾松林下分别套种1 a生火力楠、闽粤栲、苦槠、格氏栲、青栲和拉氏栲等阔叶树种的幼苗,16 a后形成郁闭的针阔混交异龄林.通过定位监测和化学分析,对上述6种混交林类型及林下未套种阔叶树的马尾松纯林的森林凋落量及养分通量进行了研究.统计结果显示,6个混交群落的年凋落量分别为7 137.3 kg hm-2、6 741.1 kghm-2、8 041.7 kg hm-2、7 151.3kg hm-2、7 533.2kg hm-2和6 149.1 kg hm-2,而马尾松纯林的年凋落量仅3 442.8 kghm-2.在所有林分的凋落物组成中,枯叶占绝对优势,占凋落物总量的49.7%～71.5%,其余依次为枯枝(5.7%～26.1%)、其它组分(5.5%～17.1%)、树皮(7.7%～18.9%)和果实(0.7%～2.0%).各混交林分中来自马尾松的凋落物占50.4%～58.0%,而来自阔叶树的凋落物占42.0%～49.6%,且两者的组成存在明显差异.各林分总凋落量的季节动态呈双峰型,第1次峰值出现在2～4月份,第2次峰值出现在8、9月份.凋落物中主要养分元素的含量依林分类型、凋落物组分和凋落时间不同而异,N、P、K、Ca和Mg的含量范围依次为3.25～12.98 g kg-1、0.23～0.97 g kg-1、0.42～4.02 g kg-1、7.34～32.57 g kg-1和1.34～5.58 g kg-1.不同的林分类型,凋落物中各养分元素的年通量大小均为:Ca＞N＞Mg＞K＞P.马尾松纯林中,通过凋落物的5种养分元素的年流通量为142.01 kg hm-2;而在林下分别套种上述6种阔叶树后,其养分年流通量依次增加到204.95 kg hm-1、223.93 kg hm-2、304.12 kg hm-2、288.46 kg hm-2、213.77 kg hm-2、238.05 kg hm-2.
基金supported by research grants from the Korea Forest Service(S121314L130100)
文摘Tropical forests play a critical role in mitigating climate change because they account for large amount o terrestrial carbon storage and productivity.However,there are many uncertainties associated with the estimation o carbon dynamics.We estimated forest structure and carbon dynamics along a slope（17.3°–42.8°）and to assess the relations between forest structures,carbon dynamics,and slopes in an intact lowland mixed dipterocarp forest,in Kuala Belalong,Brunei Darussalam.Living biomass,basa area,stand density,crown properties,and tree family composition were measured for forest structure.Growth rate,litter production,and litter decomposition rates were also measured for carbon dynamics.The crown form index and the crown position index were used to assess crown properties,which we categorized into five stages,from very poor to perfect.The living biomass,basal area and stand density were 261.5–940.7 Mg ha-1,43.6–63.6 m2ha-1and 6,675–8400 tree ha-1,respectively.The average crown form and position index were 4,which means that the crown are mostly symmetrical and sufficiently exposed for photosynthesis.The mean biomass growth rate,litter production,litter decomposition rate were estimated as11.9,11.6 Mg ha-1a-1,and 7.2 g a-1,respectively.Biomass growth rate was significantly correlated with living biomass,basal area,and crown form.Crown form appeared to strongly influence living biomass,basal area and biomass growth rate in terms of light acquisition.However,basal area,stand density,crown properties,and biomass growth rate did not vary by slope or tree family composition.The results indicate that carbon accumulation by tree growth in an intact lowland mixed dipterocarp forest depends on crown properties.Absence of any effect of tree family composition on carbon accumulation suggests that the main driver of biomass accumulation in old-growth forests of Borneo is not species-specific characteristics of tree species.
