Models for predicting the within-tree and regional variation of tracheid length and width for plantation loblolly pine
| Authors: | Joseph Dahlen, Mohamad Nabavi, David Auty, Laurence Schimleck, Thomas L. Eberhardt |
| Year: | 2021 |
| Type: | Scientific Journal |
| Station: | Forest Products Laboratory |
| DOI: | https://doi.org/10.1093/forestry/cpaa018 |
| Source: | Forestry: An International Journal of Forest Research |
Abstract
Loblolly pine is a major fibre source for the pulp and paper industry. Herewe developed the first nonlinear models
to predict the within-tree and regional variation of tracheid length and width for planted loblolly pine. Data were
obtained from macerated tracheids and near-infrared spectroscopy calibration models from trees sampled in
109 stands across the southeastern United States. The fixed effects for the final tracheid length model, which
included cambial age, height of disk within tree, and physiographic region, explained 71 percent of the variation
with root mean square error (RMSE) of 0.28 mm, while the fixed effects for the final tracheid width model
explained 57 percent of the variation with RMSE of 1.4 μm. There was significant variation in tracheid properties
across the growing regions. Tree maps showing within-tree variability in tracheid properties were produced. Five
simulated scenarios were compared using the models developed, with mean tracheid dimensions calculated
on a whole-tree basis at a first and second thinnings, and at final harvest. Also from the final harvest, the tops
of trees, and outerwood chips produced during lumber manufacturing were also simulated. For the whole tree
scenarios, both mean tracheid length and width increased with age, increasing from 2.24 mm and 40.5 μm (age
12), to 2.51 mm and 41.3 μm (age 18), and to 2.73 and 41.8 μm at age 25, respectively. The tops of the trees
at age 25 had a mean tracheid length of 2.46 mm and a mean width of 41.0 μm, while the chips had a mean
tracheid length of 3.13 mm and a mean width of 42.5 μm. Due to the models representing samples collected
from across the southeastern United States, and their relatively high precision, they are suitable for incorporation
into growth and yield systems allowing for prediction of tracheid properties.