Organic compounds in cryofolists developed on limestone under subalpine coniferous forest, Bavaria

Geoderma ◽  
1985 ◽  
Vol 36 (2) ◽  
pp. 145-157 ◽  
Author(s):  
R. Bochter ◽  
W. Zech
2018 ◽  
Author(s):  
Christian Nyrop Albers ◽  
Magnus Kramshøj ◽  
Riikka Rinnan

Abstract. Biogenic volatile organic compounds (BVOCs) are produced by all life forms. Their release into the atmosphere is important with regards to a number of physical and chemical processes and great effort has been put into determining sources and sinks of these compounds in recent years. Soil microbes as a possible sink for BVOCs in the atmosphere has been suggested, however, experimental evidence for this sink is scarce despite its potentially high importance to both carbon cycling and atmospheric concentrations of these gases. We therefore conducted a study with a number of commonly occurring BVOCs labelled with 14C and modified existing methods to study mineralization of these compounds to 14CO2 in four different top soils. Five of the six BVOCs were rapidly mineralized by microbes in all soils. However, great differences were observed with regards to speed of mineralization, extent of mineralization and variation between soil types. Methanol, benzaldehyde, acetophenone and the oxygenated monoterpene geraniol were mineralized within hours in all soils. The hydrocarbon monoterpene p-cymene was mineralized rapidly in soil from a coniferous forest but slower in soil from and adjacent beech stand while chloroform was mineralized slowly in all soils. From our study it is clear that soil microbes are able to degrade completely BVOCs released by aboveground vegetation as well as BVOCs released by soil microbes and plant roots. In addition to the possible atmospheric implications of this degradation the very fast mineralization rates are likely important in shaping the net BVOC emissions from soil and it is possible that BVOC formation and degradation may be an important but little recognized part of internal carbon cycling in soil.


Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 490
Author(s):  
Takuo Nagaike

Research Highlights: To ensure sustainable forest regeneration, it is important to clarify whether new recruits or advanced regenerants are more likely to be stripped. Therefore, the effects of bark stripping on saplings in subalpine forests with abundant saplings should be analyzed by regeneration mode, but there have been no such studies until now. Background and Objectives: I investigated the effects of bark stripping by Cervus nippon on saplings in a subalpine coniferous forest in central Japan to (1) reveal differences in bark stripping between new recruits and advanced regenerants and (2) clarify the factors affecting survivorship. Materials and Methods: A 50 m × 140 m (0.7 ha) plot was set in the old-growth subalpine coniferous forest. All trees in the plot that were ≥2 m in height were tagged, identified to species, measured diameter at breast height and recorded bark stripping by deer. These trees and new recruits were counted and measured in 2005, 2007, 2012, and 2017. I compared saplings recruited in 2007, 2012, and 2017 (“new recruits”) with existing saplings of the same size (“advanced regenerants”). Results: The density of new recruits of Abies mariesii and Tsuga diversifolia increased, whereas that of Abies veitchii decreased. The proportion of stripped saplings was greater in new recruits than in advanced regenerants, significantly so in A. veitchii, which also had the highest maximum bark stripping ratio. Factors affecting the survivorships applied by the regression tree analysis were the maximum stripping ratio of stems for the two Abies species and the initial size for the T. diversifolia. Conclusions: Bark stripping by deer was more intensive on new recruits than on advanced regenerants in a subalpine forest, and regeneration in canopy gaps might fail because of intensive bark stripping in areas overabundant in deer.


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