Understory vegetation changes, caused by forestry management, can alter the litter species composition and microclimate in situ, which while profoundly influence litter lignin degradation processes, is seldom investigated. To reveal the effects of these changes, understory vegetation in plots was treated as follows: no understory vegetation removal; only shrub removal; only herb removal; and, both shrub and herb removal. Single‐ and mixed‐species litterbags (1.0 mm mesh with uncut leaf litter) matching the treated vegetation characteristics (complied with a 7:2:1 air‐dried mass ratio for the litter form trees, shrubs, and herbs) were placed on the floor. After 2 years, 5.9% (single‐tree litter in the plots with shrub removal) to 41.4% (mixture in the plots with no understory vegetation removal) of the initial lignin content was degraded among litterbag types and plot treatments. Incidence of nonadditive effects was reduced, and the nonadditive lignin degradation rate varied but remained low among plot treatments when understory vegetation was removed. In all plot treatments, lignin degradation rate was higher in single‐shrub or single‐herb litter than in single‐tree litter (at least 9.7% ± 1.2% for the deviation). Mixtures in the plots, with no understory vegetation removal, exhibited a greater lignin degradation rate than that of the litter mixtures in the other plots. Path analysis indicated that microbial biomass nitrogen, average temperature, and lignin concentration were positively correlated with lignin degradation rate. Therefore, in addition to the litter species composition, alterations in microclimate as a result of understory vegetation changes can be a key factor that influence lignin degradation rate.

中文翻译：

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马尾松人工林下垫木去除对凋落木质素的降解

林业管理引起的林下植被变化可以原地改变凋落物的种类组成和小气候，尽管这对深刻影响凋落物木质素的降解过程却很少进行研究。为了揭示这些变化的影响，对地块下的植被进行了以下处理：仅清除灌木；仅去除草药；以及灌木和草药的清除。将与处理过的植被特征相匹配的单种和混合垃圾袋（1.0毫米网眼，未切割的树叶垃圾）（对于树木，灌木和草本植物，其风干质量比为7：2：1）放置在草坪上。地面。2年后，占总面积的5.9％（该地块中的单棵树凋落物已清除灌木）。在垃圾袋类型和地块处理之间，初始木质素含量的4％（在未去除林下植被的地块中混合）降解。当去除林下植被时，非加成作用的发生率降低了，并且非加成木质素的降解率发生了变化，但在地块处理之间仍然很低。在所有样地处理中，单灌木或单草凋落物中的木质素降解率均高于单树凋落物（偏差至少为9.7％±1.2％）。在没有去除地下植被的样地中，混合料的木质素降解率高于其他样地中的混合料。通径分析表明，微生物量氮，平均温度和木质素浓度与木质素降解率呈正相关。所以，