Treesearch

Landscape carbon (C) flux estimates help assess the ability of terrestrial ecosystems to buffer further increases in anthropogenic carbon dioxide (CO2) emissions. Advances in remote sensing have led to coarse-scale estimates of gross primary productivity (GPP; e.g., MODIS 17), yet efforts to develop spatial respiration products are lacking. Here we demonstrate a method to predict growing season soil respiration at a regional scale in a mixed subalpine ecosystem. We related field measurements (n = 396) of growing season soil respiration mostly from subalpine forests in the Southern Rocky...

Two lightning stroke data sets for the same time period from a 7854 sq.km. area in the Black Hills, South Dakota USA , one from Vaisala and the other from WSI (Weather Services International now The Weather Company) were compared with respect to number of events, number of positive and negative strokes, amplitude and number of subevents. There was also an attempt to match strokes between the two data sets. The first stroke recorded for each data set took place on June 15 2012 at 3:49 PM MDT and the last stroke for each data set occurred on June 26 2012 at 2:58 PM MDT. The WSI data set has...

Imputation models were developed to predict seedling regeneration density and composition on National Forest System (NFS) lands in Oregon and Washington. The models were based on Forest Inventory and Analysis and Pacific Northwest Regional NFS Monitoring data. Individual models were developed based on broad forest plant association groups (FPAGs) with all model development and analysis conducted in R using a most similar neighbor-like imputation approach. Model performance was evaluated based on bias, mean absolute deviation, root mean-squared error (RMSE), and error rate in correctly...

Cost-effective strategic management of aerial forest fire suppression resources involves decisions about fleet location, in order to efficiently match supply and demand. In this study, we explore the flexible design of such a system, pooling the demand of several bases into a “zone”, and analyzing alternative partitions of the territory into zones. Feasible partitions consider an upper limit on the distance between bases, and require their adjacency, within the same zone. Then, we classify the feasible partitions according to a set of six criteria and explore the non-dominated partitions....

Large air tankers (LATs) - fixed wing aircraft used for wildfire suppression - are an integral but costly tool for wildfire management. But little evidence is available indicating whether the deployment of LATs is effective at containing fire ignitions during initial attack. Using data on USDA Forest Service wildfire ignitions and LAT deployments from 2010-2012 this paper estimates the effect of deploying a LAT on the likelihood that the fire ignition is contained during initial attack. Results suggest that LATs may be effective for a subset of ignitions with moderate growth potential, but...

Individual tree crown (ITC) segmentation is an approach to isolate individual tree from the background vegetation and delineate precisely the crown boundaries for forest management and inventory purposes. ITC detection and delineation have been commonly generated from canopy height model (CHM) derived from light detection and ranging (LiDAR) data. Existing ITC segmentation methods, however, are limited in their efficiency for characterizing closed canopies, especially in tropical forests, due to the overlapping structure and irregular shape of tree crowns. Furthermore, the potential of...

Swiss needle cast (SNC) is a Douglas-fir foliage disease caused by the fungus Phaeocryptopus gaeumannii Rohde (Petrak). The spore-bearing structures of this fungus (pseudothecia) occlude the stomata in Douglas-fir needles resulting in an inhibition of gas exchange and photosynthesis, premature foliage loss, and reduced growth (Hansen et al., 2000; Manter et al., 2000). The volume growth reductions inflicted by SNC can exceed 50% in severely diseased stands (Maguire et al., 2011). Since the 1990s, the disease has continued to intensify in coastal low-elevation forests in the Pacific...

Accurate forest inventory is of great economic importance to optimize the entire supply chain management in pulp and paper companies. The aim of this study was to estimate stand dominate and mean heights (HD and HM) and tree density (TD) of Pinus taeda plantations located in South Brazil using in-situ measurements, airborne Light Detection and Ranging (LiDAR) data and the non- k-nearest neighbor (k- NN) imputation. Forest inventory attributes and LiDAR derived metrics were calculated at 53 regular sample plots and we used imputation models to retrieve the forest attributes at plot and...

In subalpine forests where snowpacks can persist for 50% of the year or longer, wintertime subnivean soil respiration constitutes a significant, but poorly understood, portion of the carbon (C) cycle. The temporal and seasonal dynamics of this flux are difficult to measure compared to snow-free respiration. This makes it challenging to fully address key knowledge gaps in high-elevation forests, including effects of tree mortality on ecosystem C fluxes. Our paper attempts to overcome these challenges by developing a new method for estimating wintertime CO2 flux from soil underneath winter...

The prediction of snowmelt in mountainous forests strongly depends on the accurate description of sensible and latent heat turbulent fluxes. Uncertainty about the within‐ canopy wind conditions especially poses a challenge, with relatively few studies examining both above‐ and below‐canopy turbulent fluxes. In this study, turbulent flux predictions from a state‐of‐the‐art watershed model GEOtop were verified against eddy covariance data from one above‐canopy tower and two below‐canopy towers in a snow‐dominated coniferous forest in south‐eastern Wyoming. The model was applied in one‐dimensi...