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Sothern Yellow Pine standing dead is it rotten?

Started by Georgia088, December 06, 2017, 08:09:21 AM

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WDH

We are not talking about hardwoods here.  You are right that slow growth in ring porous hardwoods gives lower density.  However, in SYP, the latewood is denser that the early wood.  The cell walls are much thicker in the latewood.  It is all about proportions. 
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Don P

Exactly, look for proportion of latewood, forget rate of growth. In the pic above the highest density, that is, the highest proportion of latewood happens to be in the board with the fastest growth. Proportion of latewood is not directly tied to rate of growth in distinct ring softwoods. Other factors like genetics, age, sun, site, latitude, elevation, etc, etc, etc play a stronger role in density of that group of softwoods than rings per inch.

Durability, decay resistance, is more related to heartwood formation than latewood proportion. The heartwood and sapwood contain the same early and latewood. Sapwood containing latewood rots readily, the heartwood is more durable. That is because of the extractives that infiltrate the cells during heartwood formation. Latewood will decay slower than earlywood but much faster than heartwood. Plantations are normally harvested on short rotation that doesn't allow for much heartwood.

In the plantation we are planting trees that were selected based on diameter growth. That might not be the best selection criteria if we are looking for high proportions of latewood. Fast growing trees produce a large juvenile core. The harvest cycle is short enough that heartwood formation, if any at all, is limited to that juvenile core wood. There is nothing wrong with growing softwood timber in a plantation and very high quality timber can be grown that way, it has more to do with what we are growing and how we are growing it than with how fast the plant grows.

I've worked in shops where the guys would pull out the sticks of heart pine and start counting rings per inch as a sign of quality. They could be in excess of 40 rings/inch. No doubt it is beautiful, full of heartwood. Latewood proportion is low in something like that, the rings are quite fine. Strength is low. That tree had a hard life and it shows in the meagerness of its progress. I'm not sure how this equates to quality in a plant... but that is what we as woodworkers keep telling ourselves  :).

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