[RoyalHenOil]

Larger trees grow more slowly due to increasing competition (especially for canopy space) with their neighbors.

If trees are planted with sufficient spacing, an old tree's outer growth rings will be the same density as the inner growth rings. Trees grow to the water, sunlight, and nutrients that are available to them -- up until they become diseased or they grow so large that they struggle to support their own weight (at which point they start losing branches, which means they no longer get enough sunlight). To counteract the pull of gravity, older trees stop gaining height and instead focus on adding girth (i.e., thicker growth rings).

Tree plantations achieve a higher wood output by progressively thinning the plantings as the trees mature. This allows the remaining trees to keep growing at a fast clip and results in more even grain in the lumber.

[njarboe]

I was talking about really large trees like you get in true old growth forests (ie never cut. Many people see 100 year old second growth forests and think they are old growth, but they are not).

Tree plantations are a whole different eco-system (a very improverished one like a cornfield) from an old growth forest (not really an eco-system). I would love to see tree plantations grow trees for 500 years, but I have never heard of that happening.

Check out this paper where the oldest tree in the study (651 years old) was producing the most heartwood per year of any tree in the study area[1]. Or use google scholar and search for "wood production of old growth forests" The rings on this 651 year old tree will be very thin but the volume of wood produced is large due to the huge diameter of the trunk. Have you every seen a 16 ft diameter tree? They are rare but amazing.

[https://www.sciencedirect.com/science/article/pii/S037811270...]