scholarly journals Percent canopy cover and stand structure statistics from the Forest Vegetation Simulator

Author(s):  
Nicholas L. Crookston ◽  
Albert R. Stage
2008 ◽  
Vol 23 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Treg A. Christopher ◽  
John M. Goodburn

Abstract The Forest Vegetation Simulator (FVS) estimates percent canopy cover without spatially explicit information. Estimates of canopy cover in FVS can be corrected for crown overlap, based on the assumption that trees in a stand are randomly distributed. This research assessed the accuracy of FVS estimates of canopy cover in stands with nonrandom spatial patterns. A method for measuring canopy cover within a geographic information system was developed to compare with FVS estimates of cover for 19, stem-mapped plots across Idaho and Montana. The Ripley's K(d) statistic was used to describe natural and simulated spatial patterns, so that the accuracy of canopy cover estimated by FVS could be considered for groups of plots classified as regular, clustered, or random. Results from the analyses of the effects of spatial patterns indicated that the FVS may underestimate canopy cover by 11% for plots with highly regular spatial patterns and overestimate by 2% for plots with clustered patterns. Although the magnitude of this bias likely is insufficient to justify changing the model's algorithm for canopy cover, users of this model should be aware of the potential bias that can occur as a result of assuming that trees in a stand are randomly distributed. Information on the general spatial pattern of the stand (i.e., clumped, random, and even) could be used by managers to anticipate the expected degree and direction of the bias.


2021 ◽  
Vol 748 (1) ◽  
pp. 012009
Author(s):  
Agusyadi Ismail ◽  
Yayan Hendrayana ◽  
Dadan Ramadani ◽  
Sri Umiyati

Abstract Mount Ciremai National Park forest that area had been encroached. Because of that condition, stand structure especially the species composition and vegetation structure need to be researched. The aim of this research was to identify plant species and analyze forest vegetation structure. This research was conducted between March–April 2018 in the 15.500 ha area with 0.02% sampling intensity. Data was collected using grid line method that consisted of 34 sample plots with the 10 m distance between the plots and 20 m between the lines. The numbers of identified plant species at the research location were 43 species, classified by 10 families and 24 genera. Cinnamomum sintoc has a high level of dominance species. The forest vegetation was consisting by the different growth phases. The tree phase has the highest density of 3672 species/ha, while the seedling phase was lowest density of 1060 species/ha. The forest crown stratification were consisting of A, B, C, D and E stratum. The highest number of plants were from C strata for 4651 trees and the least from A strata with 25 trees with the highest tree was 42 m. Could be concluded that the composition of Mount Ciremai National Park forest have so many number of species and complex structure vegetation forest.


Author(s):  
Kellen Nelson ◽  
Daniel Tinker

Understanding how live and dead forest fuel moisture content (FMC) varies with seasonal weather and stand structure will improve researchers’ and forest managers’ ability to predict the cumulative effects of weather on fuel drying during the fire season and help identify acute conditions that foster wildfire ignition and high rates of fire spread. No studies have investigated the efficacy of predicting FMC using mechanistic water budget models at daily time scales through the fire season nor have they investigated how FMC may vary across space. This study addresses these gaps by (1) validating a novel mechanistic live FMC model and (2) applying this model with an existing dead FMC model at three forest sites using five climate change scenarios to characterize how FMC changes through time and across space. Sites include post-fire 24-year old forest, mature forest with high canopy cover, and mature forest affected by the mountain pine beetle with moderate canopy cover. Climate scenarios include central tendency, warm/dry, warm/wet, hot/dry, and hot/wet.


2010 ◽  
Vol 52 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Mait Lang

Metsa katvuse ja liituse hindamine lennukilt laserskanneriga Tests were carried out in mature Scots pine, Norway spruce and Silver birch stands at Järvselja, Estonia, to estimate canopy cover (K) and crown cover (L) from airborne lidar data. Independent estimates Kc and Lc for K and L were calculated from the Cajanus tube readings made on the ground at 1.3 m height. Lidar data based cover estimates depended on the inclusion of different order returns significantly. In all the stands first order return based estimate K1 was biased positively (3-10%) at the reference height of 1.3 m compared to ground measurements. All lidar based estimates decreased with increasing the reference height. Single return (Ky) and all return (Kk) based canopy cover estimates depended more on the sand structure compared to K1. The ratio of all return count to the first return count D behaved like crown cover estimate in all stands. However, in spruce stand D understimated Lc significantly. In the Scots pine stand K1(1.3) = 0.7431 was most similar canopy cover estimate relative to the ground estimate Kc = 0,7362 whereas Ky(1.3) and Kk(1.3) gave significant underestimates (>15%) of K. Caused by the simple structure of Scots pine stand - only one layer pine trees, the Cajanus tube based canopy cover (Kc), crown cover (Lc) and lidar data based canopy density D(1.3) values were rather similar. In the Norway spruce stand and in the Silver birch stand second layer and regeneration trees were present. In the Silver birch stand Kk(1.3) and Ky(1.3) estimated Kc rather well. In the Norway spruce stand Ky(1.3) and K1(1.3) were the best estimators of Kc whereas Kk(1.3) underestimated canopy cover. Lidar data were found to be usable for canopy cover and crown cover assessment but the selection of the estimator is not trivial and depends on the stand structure.


2011 ◽  
Vol 87 (02) ◽  
pp. 251-259 ◽  
Author(s):  
Krish Homagain ◽  
Chander Shahi ◽  
Mathew Leitch ◽  
Nancy Luckai ◽  
F. Wayne Bell

We examined differences in stem quality, and volume and value of fibre produced by planted white spruce 16 years after vegetation management treatments in northwestern Ontario. Forest Vegetation Simulator (FVSOntario) was used to project the total and merchantable volume to age 70 and BUCK-2 was used to optimize the resulting product mix. Projected value was based on 2009 prices for hog fuel, pulpwood and SPF (spruce–pine–fir) eastern green lumber prices. At 16 years posttreatment, gross total volumes in herbicide-treated and mechanically cut plots were significantly higher (120%–165% and 94%–98%, respectively) than that in control plots (14.73 m3 ha-1). Based on height, diameter, and taper criteria, observed tree quality did not differ among treatments. The projected value of the fibre produced was 36% to 53% higher in herbicide- treated plots and 24% to 37% higher in mechanically cut plots than in control plots ($18 486.76 per ha).


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