Data_Sheet_1_Spatiotemporal trends of black walnut forest stocking under climate change.docx

Basal area is a key measure of forest stocking and an important proxy of forest productivity in the face of climate change. Black walnut (Juglans nigra) is one of the most valuable timber species in North America. However, little is known about how the stocking of black walnut would change with differed bioclimatic conditions under climate change. In this study, we projected the current and future basal area of black walnut. We trained different machine learning models using more than 1.4 million tree records from 10,162 Forest Inventory and Analysis (FIA) sample plots and 42 spatially explicit bioclimate and other environmental attributes. We selected random forests (RF) as the final model to estimate the basal area of black walnut under climate change because RF had a higher coefficient of determination (R2), lower root mean square error (RMSE), and lower mean absolute error (MAE) than the other two models (XGBoost and linear regression). The most important variables to predict basal area were the mean annual temperature and precipitation, potential evapotranspiration, topology, and human footprint. Under two emission scenarios (Representative Concentration Pathway 4.5 and 8.5), the RF model projected that black walnut stocking would increase in the northern part of the current range in the USA by 2080, with a potential shift of species distribution range although uncertainty still exists due to unpredictable events, including extreme abiotic (heat, drought) and biotic (pests, disease) occurrences. Our models can be adapted to other hardwood tree species to predict tree changes in basal area based on future climate scenarios.</p

Bottles to trees: Plastic beverage bottles as an alternative nursery growing container for reforestation in developing countries - Fig 4

<p><b>Arizona walnut seedling field relative height (A) and root collar diameter (B) growth (Means ± SE) following the first year of outplanting.</b> Container types: Coca-Cola^® bottles (Coke), Deepot^TM D27 containers (D27), polyethylene polybags (Polybag), and Sam’s Club^® bottles (Sams). Means (±SE) not accompanied by the same lowercase letters are significantly different (α = 0.05) according to Fisher’s LSD test.</p

Plastic bottles used as alternative containers for seedling production–photo by R.Heyduck.

<p>Plastic bottles used as alternative containers for seedling production–photo by R.Heyduck.</p

Mean estimates of shoot, root collar diameter (RCD), first-order lateral roots (FOLR), and overall root, and total tree morphological parameters for Afghan pine seedlings in August and November sampling periods.

<p>Mean estimates of shoot, root collar diameter (RCD), first-order lateral roots (FOLR), and overall root, and total tree morphological parameters for Afghan pine seedlings in August and November sampling periods.</p

Effects of root spiraling prevention method by opacity treatment combinations on algae growth on inner container walls.

<p>The data were collected during the August 2013 destructive sampling period. The interaction between root spiraling prevention method and opacity treatments was statistically significant (<i>P</i> = 0.01). Abbreviations are: CB (control with black color), CC (control with clear color), CG (control with green color), RB (internal ridges with black color), RC (internal ridges with clear color), RG (internal ridges with green color), SB (side-slits with black color), SC (side-slits with clear color), and SG (side-slits with green color). Means (±SE) not accompanied by the same lowercase letters are significantly different (α = 0.05) according to Fisher’s LSD test.</p