A comparison of techniques for measuring density and concentrations of carbon and nitrogen in coarse woody debris at different stages of decay

2004 ◽  
Vol 34 (3) ◽  
pp. 744-753 ◽  
Author(s):  
I F Creed ◽  
K L Webster ◽  
D L Morrison
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Significant Degree ◽  
Picea Rubens ◽  
Classification Systems ◽  
Southern Appalachians ◽  
Abies Fraseri ◽  
Carbon And Nitrogen ◽  
Comparison Of Techniques ◽  
The Relationship

This research considered the relationship between the stage of decay and the concentration of nitrogen (N, %) and the ratio of carbon to N (C/N) in coarse woody debris. Density (g/cm3) was used as an indicator of the stage of decay. In samples collected from the red spruce – Fraser fir (Picea rubens Sarg. – Abies fraseri (Pursh) Poir.) forest of the southern Appalachians, density explained up to 60% of the variation in N and C/N in coarse woody debris. The technique used to estimate density was important. Laboratory-based methods (including displacement and mensuration density) explained the greatest degree of the variation, with coefficients of determination (r2) ranging from 0.39 to 0.59 (p < 0.001) for N and from 0.39 to 0.58 for C/N (p < 0.001). Field-based methods (including penetrometer and resisto graph readings) explained a smaller but still significant degree of the variation, with r2 ranging from 0.17 to 0.25 (p < 0.01) for N and from 0.14 to 0.26 for C/N (p < 0.05). Consideration of within-bole heterogeneity in density improved the explanation of variation in N and C/N for a single bole. Density provides a continuous indicator of stage of decay that is not bound by the artificiality of discrete decay classification systems. Furthermore, statistical models relating density to N and C/N provide a means of hind casting and (or) forecasting changes in N and C/N in coarse woody debris at different stages of decay.

Coarse woody debris in old-growth temperate beech (Nothofagus) forests of New Zealand

1994 ◽  
Vol 24 (10) ◽  
pp. 1989-1996 ◽  
Author(s):  
Glenn H. Stewart ◽  
Larry E. Burrows
Keyword(s):  
New Zealand ◽  
Coarse Woody Debris ◽  
Tree Mortality ◽  
Structural Integrity ◽  
Woody Debris ◽  
Hardwood Forests ◽  
Old Growth ◽  
Carbon And Nitrogen ◽  
Decay Sequence ◽  
Nothofagus Forests

The volume, biomass, and carbon and nitrogen content of coarse woody debris were measured on three 1-ha reference plots in old-growth Nothofagusfusca (Hook. f.) Oerst.–Nothofagusmenziesii (Hook. f.) Oerst. forest on the South Island of New Zealand. Two decay sequences for logs and one for standing dead trees (snags) were recognised from two-way indicator species analysis (TWINSPAN) of up to 30 variables related to physical characteristics and structural integrity. Wood volume (up to 800 m3•ha−1) and biomass were high (up to 300 Mg•ha−1), and the inside-out decay sequence from heartwood to sapwood was unusual compared with that of other temperate hardwood forests. Coarse woody debris represented significant carbon and nitrogen pools, with ca. 150 Mg•ha−1 and 370 kg•ha−1, respectively, in one stand. The coarse woody debris component of these broad-leaved evergreen hardwood forests was much higher than that reported for other temperate hardwood forests and approaches that of many northern hemisphere conifer forests. The large coarse woody debris pools are discussed in relation to live stand biomass, natural disturbances and tree mortality, and decomposition processes.

scholarly journals Patterns of mass, carbon and nitrogen in coarse woody debris in five natural forests in southern China

2014 ◽  
Vol 71 (5) ◽  
pp. 585-594 ◽  
Author(s):  
Jianfen Guo ◽  
Guangshui Chen ◽  
Jinsheng Xie ◽  
Zhijie Yang ◽  
Yusheng Yang
Keyword(s):  
Coarse Woody Debris ◽  
Southern China ◽  
Woody Debris ◽  
Natural Forests ◽  
Carbon And Nitrogen

The aftermath of tree death: coarse woody debris and the topography in four tropical rain forests

2000 ◽  
Vol 30 (9) ◽  
pp. 1489-1493 ◽  
Author(s):  
Neil Gale
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Basal Area ◽  
Slope Position ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Dead Tree ◽  
Dead Trees ◽  
Relationship Of ◽  
The Relationship

The relationship of coarse woody debris (CWD) was examined with respect to topography and site in four lowland tropical rain forests in northern Borneo and western Ecuador. In total, 1914 dead trees [Formula: see text]20 cm diameter at breast height were enumerated in 46 ha. The basal area per hectare of dead trees varied strongly with both site and slope position. Dead basal area and its correlate dead tree density increased moving up the topographic gradient from the valleys to the ridges. Site estimates for CWD volume ranged from 96 to 154 m3·ha-1. Mean standing CWD volume was four times higher on the ridge tops (54 m3·ha-1) compared with the valley and cross-terrain areas (both 13 m3·ha-1). In contrast, downed volume did not vary with slope position. The proportions of CWD present as standing wood were two to three times higher in the Bornean sites compared with Hoja Blanca. These topographical and site differences in CWD were linked to differences in mode of tree death as well as the distribution of live trees per hectare.

Is coarse woody debris a net sink or source of nitrogen in the red spruce – Fraser fir forest of the southern Appalachians, U.S.A.?

2004 ◽  
Vol 34 (3) ◽  
pp. 716-727 ◽  
Author(s):  
I F Creed ◽  
D L Morrison ◽  
N S Nicholas
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Red Spruce ◽  
Organic N ◽  
Southern Appalachians ◽  
N Dynamics ◽  
Fraser Fir ◽  
N Source ◽  
Ammonium N ◽  
Export Signal

The red spruce (Picea rubens Sarg.) – Fraser fir (Abies fraseri (Pursh) Poir.) forest of the southern Appalachians contains a significant amount of coarse woody debris (CWD) that may affect the nitrogen (N) export signal in streams originating from this N-saturated system. Interpretation of the N sink versus source status of CWD of red spruce and Fraser fir was dependent on the method used. Over a chronosequence of decay, (1) N concentrations suggested a N sink (i.e., a net gain of N of 923% in red spruce and 563% in Fraser fir relative to N in live trees); (2) N contents that reflected changes in density suggested a smaller N sink (i.e., a net gain of N of 218% in red spruce and 125% in Fraser fir relative to N in live trees), but the stoichiometry of N and C suggested a N source in early stages of decay and a N source in the most advanced stage of decay only; and (3) N contents that reflected changes in volume suggested a N source (i.e., a net N loss of –172% in red spruce and –122% in Fraser fir). The C/N ratios in CWD suggested that the shift from a N source to a N sink represented a shift from the mobilization of dissolved organic N to the immobilization of ammonium N and (or) nitrate N. The magnitude of the net change in N contents in both red spruce and Fraser fir was amongst the highest reported in literature, suggesting that CWD plays a particularly important role in N dynamics in N saturated forests.

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