How to Find Figured Wood in Aspen Trees

Patrick N. McGovern 2018

Disclaimer:

Chain saws and cutting tools are downright dangerous!  Use all safety precautions - stay safe!   Be sure to obtain the appropriate permission before cutting trees or removing any samples.  This document and the figured wood technology is under development.  Use at your own risk!

Abstract

Aspen trees can have straight or varying degrees of wavy, undulating grain patterns known as figured wood, which lends a shimmering appearance to the wood and can have many variations of figure.  These characteristics may add considerable value as lumber or veneer and have been found to be heritable in aspen [1] and could be used in existing tongue and groove panelling markets.  These traits will be incorporated into the Open4st project by breeding figured European and native aspens with other elite project parents.  It is not uncommon to find figure in aspen clones, but it is considered a rare trait to find highly figured aspen to the degree seen in Maple.  Figure can be fairly consistent on trees with this genetic trait, within each clone and individual trees including one year whips, butt log, upper logs and branches. 

Introduction

The undulating grain patterns can often be viewed when the wood is split on the radial surface and carefully pulled apart.  Note the intense wavy grain of this small Maple figured wood axe chip which would likely result in a highly figured look when finished.  While it is easy to view figure on finished wood, it is rare to view aspen bark and predict if the wood is figured.  Here you can see the figure on the cambium surface of this "Tiger" figured board but it would be difficult to see it on the bark surface.  See the Open4st Figured Wood Photo Gallery.

On 12/31/15 a highly figured bigtooth aspen tree was located near Grand Rapids, MI (see GG12 photos).   This tree had high figure in the butt log, at 25', ~40' and in a nearby 3 year old sapling sucker stem.  We were fortunate to obtain flowering branches and mate the GG12 male clone with 4 female aspens (see GG12 Breeding photos and 2016 Crosses).  The seed was grown at Raker's Greenhouse and the seedlings will be raised to about 4' in 2016 and selected for rootability and figure.  Here is a gif image that shows the figure of clone GG12.

Materials and Methods

Tools:

Chain saw, camera with macro for closeups, tall pole pruner, splitting maul, hammer and wood chisel, pruning shears, zip bags, tape and markers, orange marking tape, binoculars

Determine aspen species and clonal boundaries:

Figured wood can be found in all aspen species.  However, the most desirable for this project is commonly known as Bigtooth aspen (P. grandidentata).   Aspens typically sprout from root suckers after a harvest or a fire creating a multi-tree cluster of the same clone, which can span for many acres.  Aspen clones have many traits that differentiate them from others.  Aspens typically bear male or female flowers that flush in April and have diverse flowering characteristics.   They have variable leaf traits such as  shape, color (Summer and Fall) and leaf drop date, which are all good clonal indicators.  Other obvious differential traits include bark color, twigs and branching habit.  We have also observed that figured aspen wood doesn't split as easily and tends to splinter upon separation.

Obtaining figured wood samples:

Once the clone size is known, determine a strategy to get samples.  Below are potential ideas from easiest to most difficult:

1) Sample small branches: Walk throughout the clonal area and look for dead vertical branches or solid branches laying on the ground that are 2" or larger in diameter.  The ideal material should be round (unstressed) with a centered pith.  I have observed stress induced figure in oval shaped stems taken near branch crotches or growing in non-vertical directions, which may be environmentally induced figure.  I have also observed figure within horizontal branches from trees known to have figure. 

Cut a straight 6" diameter branch section with as few defects (knots) as possible.  Use a wood chisel to split the sample radially and gently pry the pieces apart.  The idea is to make your split follow the grain - not explode it apart.   Note how hard you need to pry apart the pieces and if it splinters - the more the better for figured wood.  Move the pieces in the light to locate any figure.  You should be able to see and feel the undulating grain of highly figured wood in large stems but only small bands in smaller diameter wood.  In general, the figure found in the branches may be less aggressive than observed in the trunk of the same clone.

2) Sample whip sprouts via Split Wood Test:  Aspen clones will often grow 6' to 12' sucker sprouts after a harvest, fire or along open edge areas.   These one or two year whips can provide an excellent resource for testing figure in aspens using the following split wood test method.

Test setup, materials and notes:

• Obtain straight, relatively knot free whip sprouts, ideally 5/8" or more in diameter in 3" lengths with a pruning shears or saw.

  • Measure and record the small end cutting diameter using a digital vernier caliper.

• Use a hand pruning shear and make a 1" centered cut on the larger cutting end with a line that will avoid side buds.

• Gently twist and pry apart the stem with the shear blade or your fingers and observe the halves for figured, undulated grain texture. 

• Below are observations by McGovern of figured aspen split wood patterns:

  • • Zero Figure: Flat, evenly split faces, no splinters, no undulations (e.g. A502, no figure control clone). Undulation score = 0.

    • Low Figure: Flat, evenly split faces, Inconsistent & light undulations, Displays little figure when finished (e.g. AGRR1, low figure control clone).  Undulation score = 1.

    • Medium Figure: Irregular split faces, More consistent and heavier undulations, Should display figure when finished.  Undulation score = 2.

    • High Figure: Irregular split faces, Obvious & heavy undulations. Should display figure when finished.  Undulation score = 3.

• You may need to dry the samples for about 60 days for optimal figure presentation.

• See examples: Clone 25r23 Figured Split Wood,   2018 Aspen Split Wood Comparisons

3) Cut and sample a large tree:  The best way to verify if a clone has figure is to cut a 14" diameter or larger tree and split several 4" to 16" sections from the tree trunk.  It might be as simple as locating and sampling a dead standing tree, even if it has no bark or is rotting on the ground. Split the wood radially with a maul or use a splitting wedge to follow the grain with more control.   If the aggressive grain patterns indicate high figure, consider planning and finishing the piece.  Applying water or an oil based finish on the rough sawn surface to help show any figure.  Trees 6" diameter and smaller of a highly figured clone may only show tight, small bands of figure and higher figure improves with larger sized trees. 

Note that smaller trees of the same clone may have less figure. Look carefully at the bottom book matched sample in this photo and observe that the figure intensity increases towards the outer diameter.  This tangentially cut board does not bisect the center where there would be much less figure.  The center 4" may only have minor banding aberrations.  You may need to be patient for good figure.

Results

Please contact us if you find Highly Figured bigtooth aspen:  Please use our Contact Form if you find a highly figured aspen tree or if you have any questions.  We will contact you and try to determine if the clone has stable figure and will be a candidate for this project.

References:

• • 1. Fan, Y., Rupert, K., Wiedenhoeft, A.C., Woeste, K., Lexer, C., Meilan, R. (2013) Figured grain in aspen is heritable and not affected by graft-transmissible signals. Trees 27(4): 973-983.

Additional Resources:

• FindingFiguredAspens-OnePage.pdf

Highly figured aspen wall panelling