scholarly journals How to Evaluate Downed Fine Woody Debris Including Logging Residues?

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 881
Author(s):  
Nathalie Korboulewsky ◽  
Isabelle Bilger ◽  
Abdelwahab Bessaad

Volume or biomass estimates of downed woody debris are crucial for numerous applications such as forest carbon stock assessment, biodiversity assessments, and more recently for environmental evaluations of biofuel harvesting practices. Both fixed-area sampling (FAS) and line-intersect sampling (LIS) are used in forest inventories and ecological studies because they are unbiased and accurate methods. Nevertheless, most studies and inventories take into account only coarse woody debris (CWD, >10 cm in diameter), although fine woody debris (FWD) can account for a large part of the total downed biomass. We compared the LIS and FAS methods for FWD volume or biomass estimates and evaluated the influence of diameter and wood density measurements, plot number and size. We used a Test Zone (a defined surface area where a complete inventory was carried out, in addition to FAS and LIS), a Pilot Stand (a forest stand where both LIS and FAS methods were applied) and results from 10 field inventories in deciduous temperate forest stands with various conditions and amounts of FWD. Both methods, FAS and LIS, provided accurate (in trueness and precision) volume estimates, but LIS proved to be the more efficient. Diameter measurement was the main source of error: using the mean diameter, even by diameter class, led to an error for volume estimates of around 35%. On the contrary, wood density measurements can be simplified without much influence on the accuracy of biomass estimates (use of mean density by diameter class). We show that the length and number of transects greatly influences the estimates, and that it is better to apply more, shorter transects than fewer, longer ones. Finally, we determined the optimal methodology and propose a simplification of some measurements to obtain the best time-precision trade-off for FWD inventories at the stand level.

2009 ◽  
Vol 63 (3) ◽  
pp. 239-263 ◽  
Author(s):  
Michael L. Ferro ◽  
Matthew L. Gimmel ◽  
Kyle E. Harms ◽  
Christopher E. Carlton

2015 ◽  
Vol 63 (2) ◽  
pp. 115 ◽  
Author(s):  
Danswell Starrs ◽  
Brendan C. Ebner ◽  
Christopher J. Fulton

Transport and processing of allochthonous material is crucial for trophic pathways in headwater streams. Freshwater crayfish are known to affect and exploit the break-down of in-stream terrestrial plant material into detritus. We recorded Euastacus armatus (Murray River crayfish) individuals feeding on discrete patches of allochthonous material within an unregulated section of the Goodradigbee River, an upland stream in temperate Australia. Despite suggestions of aggressive territoriality, E. armatus were observed by remote and manual underwater filming to feed in non-aggressive aggregations on these piles of fine woody debris and leaf litter. On the basis of observations of 25 individuals found in the vicinity of the allochthonous patches, this population comprised mostly female individuals at smaller sizes of maturity than has been recorded for lowland populations of E. armatus. Our study confirms the importance of concentrated allochthonous food patches for detritivores, and points to the important trophic linkage between terrestrial and aquatic ecosystems via a widespread and iconic freshwater invertebrate. Moreover, these non-aggressive feeding aggregations of E. armatus challenge notions of aggression in this species that have been developed in small-scale aquarium studies.


2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Andréa B. Moreira ◽  
Timothy G. Gregoire ◽  
Hilton Thadeu Z. do Couto

2008 ◽  
Vol 25 (2) ◽  
pp. 99-102 ◽  
Author(s):  
Christopher A. Dahl ◽  
Brent A. Harding ◽  
Harry V. Wiant

Abstract In this study, we compare the efficiency of double sampling using point sampling and fixed-area plots for sawtimber volume estimates in a mixed-hardwood, oak-dominated stand. Multiple sample sizes and combinations were evaluated to determine optimum double-sample ratios. Results indicatedthat double, point-sampling schemes are more efficient in terms of field time and sampling errors than double-sampling schemes incorporating fixed-area plots. Data suggested that the most efficient ratio of measured and nonmeasured points with double sampling varies on the basis of the nonmeasuredvariable used and desired SE percentage levels for the inventory.


2013 ◽  
Vol 33 (3) ◽  
pp. 248-255 ◽  
Author(s):  
Kiomars Sefidi ◽  
Mohammad R. Marvie Mohadjer ◽  
Reinhard Mosandl ◽  
Carolyn A. Copenheaver

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