scholarly journals Estimating Coarse Woody Debris Volume Using Image Analysis and Multispectral LiDAR

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 141 ◽  
Author(s):  
Gustavo Lopes Queiroz ◽  
Gregory McDermid ◽  
Julia Linke ◽  
Christopher Hopkinson ◽  
Jahan Kariyeva

Coarse woody debris (CWD, parts of dead trees) is an important factor in forest management, given its roles in promoting local biodiversity and unique microhabitats, as well as providing carbon storage and fire fuel. However, parties interested in monitoring CWD abundance lack accurate methods to measure CWD accurately and extensively. Here, we demonstrate a novel strategy for mapping CWD volume (m3) across a 4300-hectare study area in the boreal forest of Alberta, Canada using optical imagery and an infra-canopy vegetation-index layer derived from multispectral aerial LiDAR. Our models predicted CWD volume with a coefficient of determination (R2) value of 0.62 compared to field data, and a root-mean square error (RMSE) of 0.224 m3/100 m2. Models using multispectral LiDAR data in addition to image-analysis data performed with up to 12% lower RMSE than models using exclusively image-analysis layers. Site managers and researchers requiring reliable and comprehensive maps of CWD volume may benefit from the presented workflow, which aims to streamline the process of CWD measurement. As multispectral LiDAR radiometric calibration routines are developed and standardized, we expect future studies to benefit increasingly more from such products for CWD detection underneath canopy cover.

2015 ◽  
Vol 76 (4) ◽  
pp. 322-330 ◽  
Author(s):  
Konrad Skwarek ◽  
Szymon Bijak

Abstract Dead wood plays an important role for the biodiversity of forest ecosystems and influences their proper development. This study assessed the amount of coarse woody debris in municipal forests in Warsaw (central Poland). Based on the forest site type, dominant tree species and age class, we stratified all complexes of the Warsaw urban forests in order to allocate 55 sample plots. For these plots, we determined the volume of dead wood including standing dead trees, coarse woody debris and broken branches as well as uprooted trees. We calculated the amount of dead wood in the distinguished site-species-age layers and for individual complexes. The volume of dead matter in municipal forests in Warsaw amounted to 38,761 m3, i.e. 13.7 m3/ha. The obtained results correspond to the current regulations concerning the amount of dead organic matter to be left in forests. Only in the Las Bielański complex (northern Warsaw) volume of dead wood is comparable to the level observed in Polish national parks or nature reserves, which is still far lower than the values found for natural forests. In general, municipal forests in Warsaw stand out positively in terms of dead wood quantity and a high degree of variation in the forms and dimensions of dead wood.


2010 ◽  
Vol 26 (4) ◽  
pp. 467-471 ◽  
Author(s):  
Lisa B. Kissing ◽  
Jennifer S. Powers

The ecological importance of trees lasts much longer than their life spans. Standing dead trees (snags) and fallen trunks and branches are an important component of above-ground carbon stocks and nutrient reserves, provide habitat for wildlife, and interact with disturbance regimes (e.g. by serving as fuel for fires) (Clark et al. 2002, Harmon et al. 1986, Pyle et al. 2008). Despite these diverse functions, woody debris stocks remain poorly quantified in tropical forests in general (Brown 1997), and in tropical dry forests in particular (Harmon et al. 1995). More empirical studies of the patterns of woody debris and processes that control its dynamics are needed to understand its role in global biogeochemical cycles and for ecosystem simulation models, many of which do not represent coarse woody debris (CWD) as a separate pool (Cornwell et al. 2009).


2010 ◽  
Vol 25 (4) ◽  
pp. 176-180 ◽  
Author(s):  
David Azuma

Abstract Forest Inventory and Analysis data were used to investigate the effects of a severe western spruce budworm outbreak on the dead wood component of forests in 11 counties of eastern Oregon for two time periods. The ownership and the level of damage (as assessed by aerial surveys) affected the resulting down woody material and standing dead trees. The pattern of coarse woody debris with respect to ownership and management intensity remained consistent into the next 10-year period. Harvesting tended to lower the amount of coarse woody debris on private forests. Federally managed forests had more standing dead trees than private lands, with more in the reserved than nonreserved areas. There was a reduction in the number of standing dead trees between the two periods.


2010 ◽  
Vol 56 (4) ◽  
pp. 411-420 ◽  
Author(s):  
W. B. Sutton ◽  
Y. Wang ◽  
C. J. Schweitzer

Abstract Understanding vertebrate habitat relationships is important to promote management strategies for the longterm conservation of many species. Using a modified drift fence method, we sampled reptiles and compared habitat variables within the William B. Bankhead National Forest (BNF) in Alabama, U.S.A from April 2005 to June 2006. We captured 226 individual reptiles representing 19 species during 564 total trap nights. We used canonical correspondence analysis to examine habitat associations for the reptiles sampled and we detected a distinct habitat gradient ranging from sites with greater litter depth and percent canopy cover to more open sites with greater woody, herbaceous, and coarse woody debris (CWD) coverage, and CWD volume. Little brown skinks Scincella lateralis and eastern worm snakes Carphophis a. amoenus were associated with sites with greater litter depth and canopy cover, whereas eastern fence lizards Sceloporus undulatus, copperheads Agkistrodon contortrix, and gray ratsnakes Pantherophis spiloides were associated with sites possessing greater CWD coverage and volume. We found that disturbances due to the southern pine beetle Dendroctonus frontalis were likely important for influencing reptile distributions through the creation of canopy gaps and fallen coarse woody debris. Compared to other studies, our modified drift-fence trap technique was successful for sampling larger snake species (66 snakes in 564 trap nights). We have also provided detailed schematics for constructing drift fence array and box traps used in this study.


2019 ◽  
Vol 65 (No. 10) ◽  
pp. 408-422
Author(s):  
Vahid Etemad ◽  
Mohsen Javanmiri pour ◽  
Zeinab Foladi

In a natural forest, phases of different dynamics are gradually replaced to create sustainability in the stands. Coarse woody debris is among the most significant structural elements of natural stands that perform an influential position in the identification of dynamic phases. Therefore, the focus of this study is on dead wood conditioning as one of the major structural components in determining the various dynamic phases in the northern forests of Iran as part of the temperate forests. For this study, compartment 326 of Gorazbon District was considered as one of the control parcels of Kheyroud Forest. In this parcel, 25 one-hectare sample plots were selected as permanent plots for a long-term forest structure and succession studies. The coarse woody debris by 100% sampling method was measured. The results showed that there are 8 main phases in this area (gap formation, understorey initiation, stem exclusion, volume accumulation, volume degradation, multiple, lighting, old-growth). The extensive forest area (52%) is located in the understorey initiation and stem exclusion phases. The results also showed that the total average volume of snags and logs was 41.5 m<sup>3</sup>·ha<sup>–1</sup>. Furthermore, the mean dead wood volume in decay classes 1, 2, 3 and 4 was 10.33, 12.22, 9.15 and 83.9 m<sup>3</sup>·ha<sup>–1</sup>, respectively. The average frequency of dead trees in the diameter classes smaller than 25 cm, 25–50 cm and in the diameter class more than 50 cm is 25.79, 6.93, and 4.88. The significance analysis results obtained by ANOVA test showed that there is a significant difference between volume, snag and log stock and the shape of dead wood in various dynamic phases. Therefore, in general, dead wood in the forest differs according to habitat, evolutionary stage (dynamic phases), standing volume and species diversity of the tree species.


2000 ◽  
Vol 30 (9) ◽  
pp. 1489-1493 ◽  
Author(s):  
Neil Gale

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.


2006 ◽  
Vol 36 (10) ◽  
pp. 2614-2622 ◽  
Author(s):  
Tomasz Zielonka

The amount and decay stages of dead wood and the residence time of logs was studied in old-growth spruce-dominated stands in the Tatra and Babia Góra in the western Carpathian Mountains in Central Europe. The DBH of living trees and snags as well as the dimensions of logs (with a minimum diameter of 10 cm) were measured on nine sample plots with a pooled area of 4.3 ha. For the logs, the decay stage was identified according to an eight-level decay classification. Dendrochronological cross-dating was applied to 107 wood samples of logs to determine the time since death. The average volume of living trees was 454 m3/ha and the volume of coarse woody debris (CWD) averaged 191 m3/ha. The noted volume of CWD was higher than volumes reported from previous studies in the Carpathian Mountains. On average, CWD made up 30% of the total volume (living plus dead) and varied between 49% and 21% for the stands. The average age of logs for decay class 1 was 13 years and 24, 28, 38, 45, 38, and 60 years for decay classes 2–7, respectively. Considerable variation of time since death between decay classes was probably due to a variable time while dead trees remained standing as snags.


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 901
Author(s):  
Silva Šēnhofa ◽  
Guntars Šņepsts ◽  
Kārlis Bičkovskis ◽  
Ieva Jaunslaviete ◽  
Līga Liepa ◽  
...  

European aspen deadwood is extensively studied as a habitat for saproxylic species, while less is known of its dynamics and role in carbon sequestration. We studied unmanaged mature (41–60 years), moderately overmature (61–80 years), overmature (81–100 years), and old-growth (101–140 years) and managed mature and moderately overmature aspen stands on fertile mineral soils. In unmanaged stands, marginal mean CWD volume was from 67.3 ± 12.1 m3 ha−1 in moderately overmature to 92.4 ± 5.1 m3 ha−1 in old-growth stands, with corresponding marginal mean CWD carbon pool 8.2 ± 1.6 t ha−1 and 12.5 ± 0.7 t ha−1, respectively. Both CWD volume and its carbon pool had substantial yet non-significant differences (all p > 0.05) among the age groups. High CWD volume was present in most stands, by at least two-thirds of plots comprising more than 20 m3 ha−1, and about half of CWD was larger than 30 cm in diameter. Changes in CWD species composition toward a higher proportion of deciduous deadwood in old-growth stands, together with a high volume of recently dead trees, suggest early senescence of the dominant aspen cohort.


2010 ◽  
Vol 56 (No. 9) ◽  
pp. 397-405 ◽  
Author(s):  
K. Merganičová ◽  
J. Merganič

Although coarse woody debris (CWD) represents one of the major carbon pools in natural forest ecosystems, little information is available about its CWD carbon stocks. This study demonstrates the importance of proper estimation of carbon stocks in CWD, which accounts for the decay process of CWD, on an example of a natural mountainous spruce forest located in Central Europe. The study accounts for aboveground coarse woody debris including standing dead trees, lying deadwood, and naturally formed stumps. Basic mensurational information (diameter, height, decay class) about dead wood was collected in the field during the inventory of the forests of the nature reserve Babia hora. The data were used for the calculation of CWD timber volume. In the next step, CWD timber volume was converted to carbon stock using the carbon proportion of 50.1% and density values of decay classes derived from the information published elsewhere. The analysis revealed that when CWD timber volume was converted to carbon stocks using the basic wood density of fresh wood, C stocks were overestimated by 40% or more depending on the developmental stage and elevation. The results also revealed that as the elevation increases, CWD carbon stocks decrease and the differences between the developmental stages diminish.


2007 ◽  
Vol 240 (1-3) ◽  
pp. 87-95 ◽  
Author(s):  
Scott L. Stephens ◽  
Danny L. Fry ◽  
Ernesto Franco-Vizcaíno ◽  
Brandon M. Collins ◽  
Jason M. Moghaddas

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