Treesearch

Since Parresol's (2001) seminal paper on the subject, it has become common practice to develop nonlinear tree biomass equations so as to ensure compatibility among total and component predictions and to fit equations jointly using multi-step least squares (MSLS) methods. In particular, many researchers have specified total tree biomass models by aggregating the expectations of nonlinear component equations. More recently, an alternative approach has been used wherein compatibility is ensured by specifying a total biomass equation plus one or more component disaggregation functions. Yet...

Accurately assessing forest biomass potential is contingent upon having accurate tree biomass models to translate data from forest inventories. Building generality into these models is especially important when they are to be applied over large spatial domains, such as regional, national and international scales. Here, new, generalized whole-tree mass / volume component models are discussed and tested. The models integrate principles of tree branching architecture and stem taper into compatible equation systems for estimating whole-tree mass or volume components across a range of species...

Performance of three groups of methods to estimate total and/or component aboveground biomass was evaluated using the data collected from destructively sampled trees in different parts of Oregon. First group of methods used analytical approach to estimate total and component biomass using existing equations, and produced biased estimates for our dataset. The second group used a system of equations fitted with seemingly unrelated regression (SUR), and was superior to group I methods. The third group of methods predicted the proportions of biomass in each component using beta, Dirichlet, and...

Forest mensurationists in the United States have expended considerable effort over the past century making detailed observations of trees’ dimensions. In recent decades efforts have focused increasingly on weights and physical properties. Work is underway to compile original measurements from past volume, taper, and weight or biomass studies for North American tree species. To date, taper records have been recovered from over 150,000 trees, and biomass records from another 22,000. Upon completion the database will serve many purposes including the development and testing of taper, volume,...

Tree biomass models are widely used but differ due to variation in the quality and quantity of data used in their development. We reviewed over 250 biomass studies and categorized them by species, location, sampled diameter distribution, and sample size. Overall, less than half of the tree species in Forest Inventory and Analysis database (FIADB) are without a published biomass model and most of the sampled trees are less than 13 inches diameter at breast height (d.b.h.). Although some species are well represented with biomass sampled, most focus on the aboveground components and as a...

The conversion factors (CFs) or expansion factors (EFs) are often used to convert volume to green or dry weight, or from one component biomass to estimate total biomass or other component biomass. These factors might be inferred from the previously developed biomass and volume equations with or without destructive sampling data. However, how the factors are related to tree size such as DBH, height or tree volume had not been examined. Using the tape and biomass measurement data of about 2000 destructively sampled loblolly pine trees, we developed several nonlinear equations to relate...

Interior Alaska (approx. 112 million forested acres in size) is the last remaining forested area within the United States where the Forest Inventory and Analysis (FIA) program is not currently implemented. A joint NASA-FIA inventory pilot project was carried out in 2014 to increase familiarity with interior Alaska logistics and evaluate the utility of state-of-the-art high-resolution remote sensing (lidar+hyperspectral+thermal airborne imaging) to support an FIA inventory of interior Alaska.

Models leveraging repeat LiDAR and field collection campaigns may be one possible mechanism to monitor carbon flux in remote forested regions. Here, we look to the spatio-temporally data-rich Kenai Peninsula in Alaska, USA to examine the potential for Bayesian spatio-temporal mapping of terrestrial forest carbon storage and uncertainty.

As part of a study of aquatic faunal community changes along riverine-lacustrine transition zones upstream of Lewis Smith Reservoir in northwest Alabama, USA, we collected crayfish from 60 sites in the Sipsey Fork, Brushy Creek, and selected tributaries (Black Warrior River system). After finding two unexpected and possibly-introduced crayfish species, we expanded our investigation of crayfish distributions to include crayfish obtained from stomachs of black bass (Micropterus spp.) caught at seven sites in the reservoir. To explore what crayfish species were in the drainage historically,...

Dr. Paul Van Deusen’s recent passing concluded a rich 30+-year research career dedicated to development and implementation of quantitative methods for forestry and natural resources. Since the early part of his career as a biometrician with the USDA Forest Service Southern Research Station in the 1980s-1990s and continuing with his later employment at NCASI, Dr. Van Deusen has made many research contributions that have been directly or indirectly important for the implementation of FIA data collection methods and for the analysis and interpretation of FIA data. We have attempted to...