August 28, 2018

https://www.linkedin.com/posts/activity-6439985520859758592-VTQ8

This ASP.NET application generates diameter distributions and yield for loblolly and slash pine plantations. The example shows the diameter distribution, yield by dbh and product, and summary statistics for a 25-year-old slash pine plantation with site index=65 and initial (age 10) trees/acre=350. Results can be exported into an Excel worksheet.

ASP.NET and SQL Server are being used to develop a web-based, subscription version of GML, with batch processing, genetics and silvicultural response functions, and thinning and mid-rotation fertilization at multiple ages.

July 30, 2018

Obtaining the height of trees is time-consuming and difficult, especially for species with a decurrent crown architecture. Measuring height to a fixed top diameter is one approach to avoid this problem, but that can be as subjective as total height. Another approach is to use local volume equations, which do not require height measurements. 

Local equations were developed by using Forest Inventory and Analysis (FIA) data in Tennessee.  Within a given FIA region, tree content can be estimated to any top diameter in terms of cubic ft volume, green weight, and board ft volume (Doyle and International log rules). In the example, yellow-poplar in the East Tennessee region with dbh=16 in. and top diameter=11 in. contains 129.8 bd ft (Doyle log rule), 197.7 bd ft (International log rule tables), 29.1 cubic ft, and 1923.6 lbs.

http://steveknowe.com/TennVol/LocalVolume.htm (case sensitive)

July 16, 2018

https://www.linkedin.com/posts/activity-6424736645244809216-kFit

Here is a sneak peek of a new growth and yield feature for genetically improved families in GML 1.3, which will be released in the near future. Diameter distributions and product yields can be predicted by using genetics performance rating systems, which typically consist of productivity, rust resistance, and straightness.

The example shows dbh distributions for unthinned loblolly pine (age 25, site index 75, 8×10 ft spacing) with several productivity ratings. Using a set of preliminary functions, maximum dominant height and basal area response increase with increasing site index and productivity rating, and the maximum response occurs at age 30. As the productivity rating increases, dbh distributions shift to larger diameters and chip-n-saw and sawtimber yield increases by about 10%, or 35 tons/acre. Depending on the rust and straightness ratings, a portion of the potential solid wood products can be reallocated to pulpwood or non-merchantable volume.

September 9, 2018

https://www.linkedin.com/posts/activity-6444741014832902144-0-9L

GML Extension for Natural Stands (GENS) was developed to supplement the growth of pine plantations provided by GML. GENS consists of volume growth functions for natural stands of pine, pine-hardwoods, upland hardwoods, and bottomland hardwoods with cypress. This Windows program is being migrated to ASP.NET and subscription services along with the main GML software.

Initial age, base age 50 site index, initial volume by product and species group, maximum age, and forest type are supplied to GENS by importing an Excel workbook. Volume growth is obtained by applying a compounded growth rate calculated from initial volume and volume for the grown age for a given site index. Results are stored in an Access database, and yield tables can be generated for use in optimization software.

Examples of growth for upland hardwoods and natural pine stands are shown for site index 75 in the graphs. As expected, the green weight of pine and hardwood pulpwood tends to decrease with increasing age, while pine chip-n-saw and both pine and hardwood sawtimber tends to increase.