美国俄亥俄州南部两种不同间伐强度对森林可燃物载量和碳的影响(英文)

本研究的目的是测定两种不同间伐强度下(70%和50%),美国俄亥俄州南部橡树混交林森林可燃物(包括枯落物、木本、草本和倒木)碳储量和其燃烧后可能释放的碳量。研究结果表明枯落物和木本碳含量显著高于草本部分。在50%、70%间伐和对照中,森林枯落物分别占了总的橡树混交林可燃物碳储量的36.6%,50.9%和66.0%。粗木质残体分别占了58.4%,48.0%和32.6%。小的木本和草本在总的森林可燃物中占据很小比例。在50%、70%间伐和对照三种情况下,总的森林可燃物分别是54.07t/ha、41.98t/ha和20.73t/ha。如果对这些森林可燃物进行燃烧,50%、70%间伐和对照中,其森林可燃物将释放碳量分别为90.39t/ha、70.19t/ha和34.66t/ha。虽然它们之间没有产生显著的差异,但和对照进行比较,间伐后仍产生了较多的一、二级森林可燃物。在50%、70%间伐和对照中,分别产生了25.08t/ha、23.47t/ha和14.38t/ha一、二级的可燃物。计划用火在燃烧这些可燃物成分时,在50%、70%间伐和对照中,可能会分别释放41.93t/ha、39.24t/ha和23.55t/ha碳。此研究对使用计划用火来减少引起森林火灾的森林可燃物具有一定的意义。

Fuel Loading and the Potential for Carbon Emissions from Fire Following Two Shelterwood Harvest Treatments in Southern Ohio

The purpose of this paper is to report the fuel load following shelterwood harvest of two intensities (70% residual stocking and 50% residual stocking), the total carbon content contained in these fuels, and the potential carbon emissions from fire. And the fuel load includes forest litter, woody and herbaceous plants and dead wood. The research results show that the forest litter and the woody plants display significantly greater carbon content than herbaceous plants. The forest litter represents 36.6%, 50.9% and 66.0% of the total fuel load for the 50% treatment, 70% treatment and control respectively. Coarse woody debris accounts for 58.4%, 48.0% and 32.6% of the total fuel load for the 50% treatment, 70% treatment and control respectively. Small woody and herbaceous materials contribute very little to the fuel loading in all treatments. The total fuel loading was determined to be 54.07 t/ha, 41.98 t/ha and 20.73 t/ha for the 50% treatment, 70% treatment, and the control,respectively. If all these fuels were consumed in a wildfire, it is estimated that the total carbon compound emissions from a fire would be 90.39 t/ha, 70.19 t/ha, and 34.66 t/ha, in the same respective order. The harvesting treatments produced more 1～10 hours fuels than the control, although not significantly between them. The 50% treatment and 70% treatment produced 25.08 t/ha and 23.47 t/ha of 1～10 hours fuels, respectively, compared to 14.38 t/ha in the control. A prescribed fire would more likely consume only the fuels in this fuel category, thus emitting 41.93 t/ha, 39.24 t/ha and 23.55 t/ha of carbon compounds from the 50% treatment, 70% treatment,and the control, respectively. This study may be worthwhile to account for the reduction in carbon emissions obtained when prescribed burns are implemented as a fuel reduction strategy in forest carbon offset projects.