Atmospheric carbon dioxide [CO2] has increased dramatically within the current life spans of long-lived trees and old forests. Consider that a 500-year-old tree in the early twenty-first century has spent 70% of its l...Atmospheric carbon dioxide [CO2] has increased dramatically within the current life spans of long-lived trees and old forests. Consider that a 500-year-old tree in the early twenty-first century has spent 70% of its life growing under preindustrial levels of [CO2], which were 30% lower than current levels. Here we address the question of whether old trees have already responded to the rapid rise in [CO2] occurring over the past 150 years. In spite of limited data, aging trees have been shown to possess a substantial capacity for increased net growth after a period of post-maturity growth decline. Observations of renewed growth and physiological function in old trees have, in some instances, coincided with Industrial Age increases in key environmental resources, including [CO2], suggesting the potential for continued growth in old trees as a function of continued global climate change.展开更多
We analyze the structure and composition of old-growth wet evergreen forest of Nelliampathy hills, the chain of hills lying immediately south of Palghat Gap, in the southern Western Ghats of India. We sampled 30 plots...We analyze the structure and composition of old-growth wet evergreen forest of Nelliampathy hills, the chain of hills lying immediately south of Palghat Gap, in the southern Western Ghats of India. We sampled 30 plots of 0.1 ha each （50 m × 20 m） at six locations enumerating all plants ？ 10 cm girth at breast height. We pooled the data and computed various structural parameters. There were 152 species of 120 genera and 51 families of the study area. Of these, 118 （77%） were trees, 24 were climbers （16%） and 10 were shrubs （7%）. Species richness varied from 58–99 per 0.5 ha sample and Shannon indices of diversity ranged from 4.4 to 5.2. Fifty-nine per cent （89 species） of the species were Indian Sub-continent elements and 34% （51 species） are endemic to the Western Ghats. Fifteen species are listed in various threat categories. Aglaia and Litsea were the most species-rich genera. Numbers of families ranged from 27–43 per 0.5 ha sample. Euphorbiaceae and Lauraceae were the most species-rich families. Stand density varied from 1714 to 2244 stems·ha？1 and basal area from 53.6 to 102.1 m2·ha？1. The vegetation was dominated by 3–6 species and six dominance patterns characterized the species composition within the hill complex. The old-growth evergreen forests of Nelliampathy exist as small fragments rich in biodiversity and can be used as benchmarks for comparison with disturbed forests.展开更多
为了解南宁市武鸣区古树资源现状,探究其空间分布和影响古树分布的地理因素,结合实地调查和地理信息系统(Geographic Information System,GIS)技术,分析武鸣区古树资源和空间分布特征。结果表明,武鸣区共有古树2538株,隶属于27科46属55...为了解南宁市武鸣区古树资源现状,探究其空间分布和影响古树分布的地理因素,结合实地调查和地理信息系统(Geographic Information System,GIS)技术,分析武鸣区古树资源和空间分布特征。结果表明,武鸣区共有古树2538株,隶属于27科46属55种;优势科为无患子科(Sapindaceae)、桑科(Moraceae)、桃金娘科(Myrtaceae)、壳斗科(Fagaceae)和樟科(Lauraceae);优势属为龙眼属(Dimocarpus)、榕属(Ficus)、蒲桃属(Syzygium)和樟属(Cinnamomum);优势种为龙眼(Dimocarpus longan)、高山榕(Ficus altissima)、榕树(Ficus microcarpa)、乌墨(Syzygium cumini)和樟(Cinnamomum camphora)。三级古树最多,特级古树最少。大多数古树生长状况良好,94.84%为正常株。特级古树主要分布在武鸣区东部和西部;一级古树主要分布在武鸣区外围;二级、三级和准古树在所有乡镇均有分布。古树分布呈较强空间集聚性,有1个高密度区中心和4个次密度区中心;城厢镇古树最多,甘圩镇古树最少。耕地中分布的古树最多,其次为林地;建设用地和水域中分布的古树均较少;草地和裸地中均无古树分布。古树喜分布在阳坡、缓坡和无坡向区域。赤红壤中分布的古树最多,其次为水稻土。武鸣区古树资源丰富且极具价值;古树整体生长状况良好,需对其进行定期调查和评估及科学养护。展开更多
基金Supported by Discovery Project Number DP0879531 of the Australian Research Councila University of Western Sydney International Research Schemes Initiative (IRIS) (71827)+2 种基金the National Science Foundation, Divisionof Integrative Organismal Systems (0517521)sabbatical support from Boston University to NGPfrom the Bushfire Cooperative Research Centre.
文摘Atmospheric carbon dioxide [CO2] has increased dramatically within the current life spans of long-lived trees and old forests. Consider that a 500-year-old tree in the early twenty-first century has spent 70% of its life growing under preindustrial levels of [CO2], which were 30% lower than current levels. Here we address the question of whether old trees have already responded to the rapid rise in [CO2] occurring over the past 150 years. In spite of limited data, aging trees have been shown to possess a substantial capacity for increased net growth after a period of post-maturity growth decline. Observations of renewed growth and physiological function in old trees have, in some instances, coincided with Industrial Age increases in key environmental resources, including [CO2], suggesting the potential for continued growth in old trees as a function of continued global climate change.
基金support from the Ministry of Environment and Forests, Government of India
文摘We analyze the structure and composition of old-growth wet evergreen forest of Nelliampathy hills, the chain of hills lying immediately south of Palghat Gap, in the southern Western Ghats of India. We sampled 30 plots of 0.1 ha each （50 m × 20 m） at six locations enumerating all plants ？ 10 cm girth at breast height. We pooled the data and computed various structural parameters. There were 152 species of 120 genera and 51 families of the study area. Of these, 118 （77%） were trees, 24 were climbers （16%） and 10 were shrubs （7%）. Species richness varied from 58–99 per 0.5 ha sample and Shannon indices of diversity ranged from 4.4 to 5.2. Fifty-nine per cent （89 species） of the species were Indian Sub-continent elements and 34% （51 species） are endemic to the Western Ghats. Fifteen species are listed in various threat categories. Aglaia and Litsea were the most species-rich genera. Numbers of families ranged from 27–43 per 0.5 ha sample. Euphorbiaceae and Lauraceae were the most species-rich families. Stand density varied from 1714 to 2244 stems·ha？1 and basal area from 53.6 to 102.1 m2·ha？1. The vegetation was dominated by 3–6 species and six dominance patterns characterized the species composition within the hill complex. The old-growth evergreen forests of Nelliampathy exist as small fragments rich in biodiversity and can be used as benchmarks for comparison with disturbed forests.
