Sequestration And Distribution Of Carbon In Huitong, Hunan As Affected By Some Different Kinds Of Conversions Of Cropland To Forestland

The raise of carbon dioxide is one of the worst environment problems which peple are confronted with. Forest is the first major form of terrestrial ecosystems. It plays great roles in stopping carbon dioxide from increasing. Conversion of cropland to forestlands is one of the six forestry ecotypic projects. Not only it can reduce the loss of water and soil in sloping field, but also can absorb the atmospheric carbon dioxide. In this paper, comparative analysis biomass, carbon storage of 5 artificial forests in rehabilitated lands in Huitong, Hunan. The 5 different afforestation types are as follows: Pinus massoniana, Cinnamomum camphora, Elaeocarpus sylvestris x Cinnamomum camphora, Elaeocarpus sylvestris x Michelia chapensis,Michelia chapensis×Manglietiainsignis. The main results of the research are as follows:There are some differences in carbon content between different trees, from 43.7～59.5%. The carbon content of different trees varied in the following order: Michelia chapensis(54.4%)> Pinus massoniana(52.6%)> Cinnamomum camphora(52.2%)> Elaeocarpus sylvestris (51.7%-52.1%)> Manglietia insignis (51.1%). The carbon content of under-stratum ground covers in Elaeocarpus sylvestris x Michelia chapensis is the most biggest(53.8%), and in Michelia chapensis×Manglietiainsignis is the least(43.8%). The soil organic carbon contents of plantation lands decreased with the increase of soil deepness. The calculated result of soil organic carbon content was the following:the soil organic carbon content offorest land of Michelia chapensis×Manglietia insignis forest (1.485%), that of Elaeocarpus sylvestris×Michelia chapensis forest (1.346%), that of Elaeocarpus sylvestris×Cinnamomum camphora forest (1.340%), that of Cinnamomum camphora forest (1.207%), that of Pinus massoniana forest (0.786%).The carbon storage of 5 different forests varied in the following order:Michelia chapensis×Manglietia insignis forest (120.967 t/hm2)> Elaeocarpus sylvestris×Cinnamomum camphora forest(106.84 t/hm2)> Elaeocarpus sylvestris×Michelia chapensis forest(105.973 t/hm2)>Cinnamomum camphora forest (98.616 t/hm2)> Pinus massoniana forest(77.457 t/hm2). For Pinus massoniana forest,0～60 cm soil (74.497 t/hm2), under-stratum ground cover (1.488t/hm2), arbor (1.472 t/hm2); for Cinnamomum camphora forest,0-60 cm soil(97.983t/hm2), arbor(0.633t/hm2); for Elaeocarpus sylvestris×Cinnamomum camphora forest,0～60cm soil(104.792 t/hm2), under-stratum ground cover (0.829 t/hm2), arbor(1.219 t/hm2); Michelia chapensis×Manglietia insignis forest,0～60 cm soil(119.483 t/hm2), litter amount(0.253 t/hm2), under-stratum ground cover (0.976 t/hm2), arbor(0.255 t/hm2); Elaeocarpus sylvestris×Michelia chapensis forest,0～60 cm soil(104.547 t/hm2), litter amount (0.243 t/hm2), under-stratum ground cover (0.984 t/hm2), arbor(0.199 t/hm2). According to the above, this paper concluded that the mixed forest was the effective measure for increasing the forest ecosystem organic carbon accumulation, the effect of the Michelia chapensis and Manglietia insignis forest was best.