CHANGES IN FOREST FLOOR ORGANIC-MATTER AND NUTRIENT CONTENT FOLLOWING CLEAR CUTTING IN NORTHERN HARDWOODS
CHANGES IN FOREST FLOOR ORGANIC-MATTER AND NUTRIENT CONTENT FOLLOWING CLEAR CUTTING IN NORTHERN HARDWOODS
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DOI：
10.2307/1936666
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发表时间：
1981-01-01
期刊：
影响因子：
4.8
通讯作者：
COVINGTON, WW
中科院分区：
文献类型：
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作者：
COVINGTON, WW
二级演替序列的14个北方阔叶林[组成针樱桃，桦树，条纹枫木，糖枫和水曲柳]林分进行了采样，森林地面有机质和养分含量。在第一个15年的皆伐后，森林地面减少了30.7毫克/公顷，下降了50%以上。森林地面和采伐剩余物的减少可能大于活生物量的增加。在接下来的50年中，森林地面增加了28.0毫克/公顷，到64年是56.0毫克/公顷的渐近线的5%以内。对14个林分中的6个进行了养分分析。Mg、K和N含量没有表现出演替规律。钙浓度显着较高的林分中，森林地面质量低。森林地面质量的最初减少是由于较低的树叶和木材凋落物下降和更快的腐烂造成的更高的温度，水分含量和营养水平和早期演替凋落物更容易分解。森林地面的恢复主要是由于木材凋落物的数量和直径的迅速增加。北方阔叶林生长模拟器JABOWA预测，到10-20年，木质凋落物的增长率最大，到30-50年趋于平稳。森林地面和采伐迹地作为营养源的功能明显相似，这对恢复过程可能很重要。在最初的15年里，森林地面是营养物质的主要来源，释放出净含量约为1000万吨。800 kg/ha N.在此期间，林分凋落物分解过程中的N固定作用可能占到林分释放N的1/2。15年后，随着营养物质和有机物质的积累，森林地面不再是营养物质的来源，而是营养物质的汇。到第15年，斜线可能从一个汇的功能转移到一个源，提供N的持续快速N积累超过15年的植被。
A secondary succession sequence of 14 northern hardwoods [composed of pin cherry, birch, striped maple, sugar maple and ash] stands was sampled for forest floor organic matter and nutrient content. During the first 15 yr following clear cutting, the forest floor decreased by 30.7 Mg/ha, a decline of over 50%. The decrease in the forest floor and slash (logging residue) may be greater than the increase in the living biomass. During the next 50 yr, the forest floor increased by 28.0 Mg/ha and by year 64 was within 5% of an asymptote of 56.0 Mg/ha. Nutrients were analyzed in 6 of the 14 stands. Mg, K and N concentrations showed no successional pattern. Ca concentrations were significantly higher in the stands in which forest floor mass was low. The initial decrease in forest floor mass is attributed to lower leaf and wood litter fall and to more rapid decay resulting from higher temperature, moisture content and nutrient levels and to early successional litter being more easily decomposed. The recovery of the forest floor is explained primarily as resulting from the rapid increase in the quantity and diameter of wood litter fall. JABOWA, the northern hardwood forest growth simulator, predicts a maximum rate of increase in woody litter by years 10-20 with a leveling off by years 30-50. An apparent asynchrony in function of the forest floor and slash as nutrient sources may be important to the recovery process. During the first 15 yr the forest floor is a major source of nutrients, releasing a net amount of .apprx. 800 kg/ha of N. During this period N immobilization in the decay of slash may account for as much as 1/2 of the N released from the forest floor. After year 15 the forest floor is no longer a source but a sink for nutrients as nutrients and organic matter accumulate. By year 15 the slash probably shifts in function from a sink to a source, providing N for the continuing rapid N accumulation in vegetation beyond year 15.