冰雪灾害对杉木林地养分分布的影响

2008年1月至2月,我国南方发生了严重的冰雪灾害,受害的森林地面达2.09×106km2。为了了解冰雪灾害对杉木的损害和由此引起的林地养分分布特点,作者调查粤北一个杉木林地的受害情况。冻雨在杉木枝叶上形成冰柱,造成所有的林木折冠。林木折断的高度和胸径呈显著相关。树冠残体的养分总浓度随残体组分而变化,呈理叶>皮>枝>干。树冠残体的干重达19.11t·hm-2,枝、树干、叶和皮分别占37%、28%、27%和8%。2008年树冠残体的养分分布随组分而急剧变化,其中叶的养分量占残体养分总量的70%,枝、干和皮分别占13%、7%和10%。2008年杉木林地的N、P、K 的积累量为105067.9 t·hm-2,杉木残体、凋落物和土壤分别占0.18%、0.03%和99.79%。养分积累量在树冠残体各组分和凋落物中的排序为N>K>P,而在土壤中为K>N>P。2009年的凋落物中N和P浓度大于2008年的凋落物,而K浓度小于后者。2009年的干和皮残体中N和P浓度略大于2008年的干和皮残体,而K浓度正好相反。2009年的干和皮残体中的N和P储量与2008年接近,K储量略小于后者。2009年的凋落物中N、P和K储量大于20...

Impact of ice-snow damage on nutrient distribution of a <Emphasis Type="Italic">Cunninghamia lanceolata</Emphasis> woodland

During January to February in 2008,severe ice-snows occurred on 2.09 ( 106 km2 of south China and caused tremendous damage to the forests. Stem damage and crown debris input from the ice-snow in a Cunninghamia lanceolata stand in northern Guangdong Province,China,were investigated to determine the extent of ice-snow damage to trees and the nutrient distribution characteristics on woodland. Icicles were produced on branches and leaves of the C. lanceolata trees by sleets,resulting in all live trees were damaged by stem breakage. A strong positive correlation was found between the broken position of trees and diameter at breast height (DBH). Nutrient concentrations varied according to components of crown debris. Total nutrient concentration graded in the following order: leaves > stembark > branches > stemwood. Crown debris input from ice-snows was 19.11 t·ha-2,and branches,stemwood,leaves and stembark accounted for 37%,28%,27% and 8%,respectively. Nutrient distributions between components of crown debris differed drastically in 2008. The contribution of leaves to total nutrient accumulation of crown debris was 70%,whereas branches,stemwood and stembark contributed 13%,7% and 10%,respectively. Accumulations of N,P and K by the woodland were 105067.9 t·ha-2 in 2008,and the nutrients of crown debris,litter and the stand soil accounted for 0.18%,0.03% and 99.79%,respectively. The order of nutrient accumulation in leaves,branches,stembark,stemwood of crown debris and litter was N＞K＞P,but the nutrients stored in the soil were in the order of K > N > P. The N and P concentrations of litter in 2009 were greater than those in 2008,whereas its K concentration was smaller than that of the latter. N and P concentrations of stemwood and stembark in 2009 were slightly greater than those in 2009,whereas their K concentration was smaller than the latter. The N and P accumulations of stemwood and stembark of crown debris in 2009 were close to those in 2008,whereas their K accumulation was slightly smaller than the latter. The N,P and K accumulations of litter in 2009 was greater than those in 2008.