A Greener Construction Sector due to Diameter Breast Height

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A Greener Construction Sector due to Diameter Breast Height

Diameter Breast Height (DBH) is a timber-industry gauging factor used to determine the economic feasibility of felling a tree for lumber. It’s a simple measurement with the diameter of the usable trunk material (no bark) taken ~ 4-1/2’ from the ground (Breast Height). An 18-22” DBH was once considered the economically viable measurement for Spruce Pine Fir (SPF) strands providing larger dimensional lumber. These tree sizes were readily available in old growth forests. Timber terms and data loosely collected from both:

Duane Bristow’s Field Forester’s Perspective as Applied In the Appalachian Hardwoods of Eastern Kentucky

and

John Mack’s Economics of Forest Resources

To open a construction component design blog with forestry and timber terms may seem a little odd. This is a blog on positive outcomes with lumber and construction intelligently adapting to the loss of old growth and scarcity of larger dimensional products (2×8, 2×10 & 2×12).

diameter-breast-height

This boon of compatible technology development is obviously economically driven. ~50-years growth cycles, under ideal growing conditions, are now required for commercial timber strands to reach the DBH requirements for larger dimensional products. This is easily extended well passed 70-years or more due to likely variables of a complex environment (severe weather, drought, pests and fire).

Comparatively, SPF timber can attain a 10″ DBH and profitably harvested as 2x4s at ~23 years of age (Frank Roth, Thinning to Improve Pine Timber). Additional attributes of spruce pine and fir softwood strands are their typical yield of tall straight trunks with few knots or other blemishes. Properly managed strands bring a much greater Return On Investment (ROI) to the timber companies and are sustainable resources for the planet at large.

“For every ton of wood grown, a young forest produces 1.07 tons of oxygen and absorbs 1.47 ton of carbon dioxide.”  Diaphragms and Shear Walls (American Plywood Association).

For 2×4 construction, to less waste on site, less energy during construction and better insulation, some analysts place softwood component construction as the greenest construction sector by 35% over everyone else.  Take a deep breath, get a cup of ice water and kick back with some sunscreen applied on your days off!

Mike Sharkey – Design Professional

Gould Design, Inc.

2 comments

  1. Thanks Gold! I’m actually now feeling remiss by not including the advances made from the advent of plywood to the extensive range of structural members now forming the EWP sector (Engineered Wood Product). The range of uses for plywood sheets is now matched by structural EWP beams exceeding all load bearing and span lengths achieved by natural lumber. Thank You for your insight.
    VR
    Mike Sharkey

  2. Engineered wood, also called composite wood, man-made wood, or manufactured board; includes a range of derivative wood products which are manufactured by binding the strands, particles, fibers , or veneers of wood, together with adhesives , to form composite materials . These products are engineered to precise design specifications which are tested to meet national or international standards. Engineered wood products are used in a variety of applications, from home construction to commercial buildings to industrial products.