Wood Grain

The grain pattern in this hickory board is easily seen.

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The large Douglas fir, 30 inches in diameter at chest height, was leaning over the road on the corner of our lot. It was hard to maneuver around and the fire department complained that they couldn’t get their truck past it. It had to go. It was interesting but sad to watch the giant crash to the ground, get sawn into ten-foot lengths and stacked near where it had once stood. I counted the growth rings on the largest portion and realized that this tree was already well-established when Theodore Roosevelt and the Rough Riders charged up San Juan Hill in 1898.

As I studied the concentric rings on the base of the trunk, I wondered at the lumber this tree would yield. I was determined that this tree would be more than just firewood and had purchased a milling device to attach to my chainsaw so I could convert the logs into boards. Although Douglas fir is known for its straight grain, there could be some real surprises inside those logs and this coming summer I am going to find out.

As I have become more interested in woodworking, I have learned a lot about wood grain and wood figure and the differences between the two and the uniqueness of each species.

Wood begins in the cambium layer just under the bark of the tree. Two types of wood cells are generated there. The majority are longitudinal cells, 100 times longer than they are wide, that align themselves with the axis of the trunk, limb or root. Simply put, this is the grain of the wood. Other cells, called ray cells, orient from the pith or center of the tree radiating outward toward the outside. These cells are quite variable in that some trees, such as white oak, have a lot of them, and other trees do not. These cells don’t offer strength but do add character and are part of the figure of the wood.

In the spring, the cambium grows wood cells rapidly, creating light-colored sapwood. Sapwood is living tissue that conducts the water and nutrients within the tree. As the season progresses, the cambium production slows down and the resulting summerwood is darker colored, harder and denser than the springwood, creating distinct concentric growth rings. Season after season as the tree continues to grow, the sapwood eventually dies, leaving behind cell walls composed mostly of cellulose bound by a glue-like substance called lignin. This is the heartwood and it is usually darker than the growing sapwood.

Wood grain also has a texture. Tree species with small diameter longitudinal cells have compact dense wood and are said to be fine-grained. Species with larger diameter longitudinal cells are less dense and are said to have a coarse texture.

We all learned in school that hardwoods are deciduous trees and softwoods are coniferous or evergreen trees. That isn’t the only difference though. Hardwood trees have vessel elements, specialized longitudinal cells that are much larger than regular longitudinal cells. When these are sliced open in the milling process, they leave tiny holes or pores in the wood. This makes hardwood look very different from softwoods.

Hardwoods that have pores concentrated in springwood are known as ring-porous woods and display a strong grain. Finer grained woods have the pores evenly distributed through the springwood and the summerwood and are known as diffuse porous woods.

Wood “figure” is different from grain and combined with the way the wood is milled helps determine the character of the wood and what it will be used for. More on that next time.

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Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates. Buying wildlife plates is a great way for non-hunters and hunters alike to support wildlife-based recreation like birding.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

And tell them that you heard about it from Nature-track.com!

Wildlife License Plates

Great news! as of 2024, there are three NEW designs for license plates. They still are bluebird, cutthroat trout and elk, but they are beautiful.

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program.

I think it is time we let the Legislature know that Idahoan support wildlife funding and that we would like to see these generic plates come to fruition.