So I just spent all day cutting up an unproductive plum tree I took most of down this winter. While I am doing a Hail Mary graft on the base and or suckers with a preferred varietal, I should not judge cutting trees as a wipe sawdust off. I heat my house with wood. And if it matters, you all seem like good people to me.
I have done a ton of research on dendrology and forest biomass accumulation as a education ranger in Olympic and Redwood NP. I was told to stop by my boss because I got too wonky. Most of my knowledge is about NW species and the SE’ deciduous forest has important differences that I should not pretend to know about. However, Robert, while of course your points about tree growth rates are useful in selective logging of second growth to maximize regrowth, It seems correlated that the largest biomass forests on earth like those I have lived in are also sequestering more carbon each year they grow intact (Noss’ book on Redwood Ecology), with trees that grow faster each year (on average) until their heartwood overtakes their sap wood and chokes the cambium. This limits the Redwood trunk lifespan to about 2500yrs because the heartwood increases at a faster exponential rate to the sapwood. At the same time, these Redwood trees are unique as conifers able to reiterate from any part of the plant like vines. Either way, it is generally true of coniferous trees and forests of the west that they grow more aggregate biomass the older they are, and this makes sense if you think about the increase in photosynthetic surface area with a taller canopy with mixed heights of understory beneath. Of course a fourth year tree has greater potential to put on more relative biomass it’s fifth year, but that’s based on a much smaller base. It’s like a small economy growing at 12% a year, whereas a massive one like the US can’t sustain more than 2-3% but that’s still a lot more money accumulation overall than the developing country. A mature forest has more photosynthetic area to power carbon sequestration, sugar production and all the life processes and ecosystem benefits that result.
That being said, we have finally tipped towards more Redwood growth than is being cut down with selective logging in Redwood country’s second growth along the lines of points Robert made about how trees grow to fill gaps in the canopy from fallen trees. When thinning second growth and taking some larger trees for some short term economic benefit (their wood is also vastly better) but still considering longterm sustainability and profit, we take out a large percentage of small trees and a very small percentage of the larger trees, and none of the truly old growth (250yrs+) ideally.
Back to the original post, I think you will do the right thing for your situation given that you seem to care and seek advice. I would prioritize summer shade in your climate, but I am from the temperate rainforest and can’t take heat. In looking for your tree/trees to take out, you could remove one that shades prized trees that will be north of your house site and they would help make up for the carbon and habitat loss in the tree you take. Ultimately, A good house site and build can save many trees in the long run by reducing heating costs if you use wood, so that may be more important than any individual tree if it’s not really that old. My neighbor cut down some trees here that were 24” thick and 18yrs old.