I do agree that there is indeed a logger myth out there that considers old wood to be decadent, but your arguments to that effect are not accurate in my thinking. Not because I'm an old logger who has cut a lot of trees down for huge lumber mills, I'm not an old logger, and although I just got a small mill, I haven't used it yet. But I will. I have, however cut down a lot of trees for firewood in my 48 years, and as a tree planter, and as a kid growing up in serious logging country, I've seen a lot of stumps. Growth rings are, indeed, thicker when the tree grows faster or more in a given year, and thinner on slow growing years. This is how tree scientists can tell if a tree had a bad year based on some small local event like another tree falling on it, or a larger climatic event like a volcanic eruption. All the old trees will have a tighter growth ring at the year of a large climate event, as an example, and if they were downwind from the fallout from the volcanic ash, they might have a great boost in growth as a result of this nutrient gain, and thus have more growth/larger summer growth rings for a while in the few years following. I've seen tree rings that are small for a while, then large for a while then small again. This scenario might look like this in the reality of the tree: when it was a seedling/sapling it grew up in shade of other trees so it's growth rings were small, then one of the large shading trees nearby fell and so the sapling had some extra light so it grew faster and it's growth rings got further apart, then the already mature and strong branches of the other larger shading trees expanded into the gap in the canopy, closing most of the canopy to the younger tree before it got to full height, so it's growth rings got small again for a while... I've seen this, or other iterations of it many times.
“overaged trees are mostly dead and grow slower, just look at how the rings get skinnier as they go out!” This logger fallacy that was used to validate cutting down our greatest forests is just a demonstration of geometric illiteracy, as the skinny rings are going around a much larger circle!
maybe. It depends on a lot of things.
Larger, older trees grow much more biomass per year,
. A young tree the size of a coffee can is blasting a lot of carbon out of the air and building tons of soil, and the OP is talking about taking down a lot of these, OR a large tree. There is a difference to that and what you said, a big difference. While I do agree with your statements about the watershed, wildlife, et cetera, there are always going to be upsides and downsides to making a permacultural design or material choice and it comes down to context and site specifics; permaculture is never cut and dry black or white, it is infinite shading on infinite colors.
taking out a big tree is exponentially worse than taking out a small one
I believe Bill Mollison was speaking of taking down virgin forest. This forest is likely second or third growth, maybe forth. My guess without knowing any specifics of the species or site is that even in those large trees, the growth rings are mostly fat, not skinny. If a tree falls in the forest, and nobody makes use of it, then it will likely rot and most of it's carbon will off gas to the atmosphere. Not that rotting wood is not essential to the forest. It is. I'm just making a point. You can lock that carbon in much longer term storage by building with it or by making char or hugulkultur with it. With huguls the carbon gets locked into the soil below grade in the bodies and wastes of fungi and microbial bacteria. With biochar the carbon is locked in for centuries.
But Bill Mollison is pretty explicit that permaculture ethics do not validate cutting down established forest for doing permaculture
If you are going to make a house or use wood for anything in your life, some trees are gonna be a dying; better to be the guy doing the selecting, clearing, et cetera, and do it consciously then have some distant unknown clearcut (that was very likely made with lots of large trees falling for nothing so that the loggers can get at the choice mill trees, as well as tons of other collateral damage including burning slash piles, and massive eroding road networks) burdening your conscience. I've lived in logging country most of my life, and have seen it all, even recently--like last week when I was huckleberry picking. You can always sequester a ton of carbon in your garden and forest soils with dead branches turned into biochar, to make up for the carbon loss of taking trees down, and you can always plant trees to make up for lost trees, and you can increase wildlife habitat on an acre with small ponds, bat boxes, owl and bird house, butterfly gardens, et cetera. I would suggest, picking a place by the road if that is on the south side, as you seem to indicate. Clear that area and put your house and garden as close to the road as bylaws or your need to be away from traffic allow. I would clear more than you think is necessary, not because I think clearing a ton of trees is a great thing (Bill Mollison and Ben Z are on the right wavelength in this direction of thought), but because it really, really sucks when a tree falls on your house. I've seen whole houses crushed to splinters by a large tree with canopy limbs. I would do the biochar I mentioned and build deep biochar rich beds and hugulkulturs and plant a lot of fruit and nut trees around them in biochar pits beside the stumps of the trees you took down (the fruit tree will utilize the root network and bio community in the soil), and these trees will be in the place of the other trees that might have fallen on your house but because you can choose varieties that are shorter you will thus not have such a worry of them falling on your house. These fruit trees can grow a long time, and you can plant more as they age.
if i want to grow anything, i also need to cut down some trees to get a southern exposure. I plan to do that at the road to minimize the impact, or maybe there is already enough clear to support a garden.
I think that my discussion on the topic was speaking of growth rings or growth rates, regardless of tree species, or forest systems, or management systems, that growth rings do not necessarily get smaller as a tree gets older. This may be true of Redwoods, once they get to an extreme old age, but I'm speaking generally, of trees. If a tree has growth rings that are countable, then the width of those rings directly correlate to how good of a season it had in terms of it's primary needs: sun, nutrients, moisture, and in terms of how these needs are effected by outside influence. Anything that deprives a tree of any of these will hinder it's growth and thus create smaller growth rings, and any factor that increases these needed inputs will create greater growth, and this is correlated to larger growth rings. A pair of tree rings is produced annualy. The thinner one is produced during it's slower growing or in extreme cold climates, dormant period, whereas the fatter ring is produced during the intense growing season that peaks at the summer solstice. Most of the forests that I have seen logged, where I planted trees (in the North Coast Temperate Rainforest), were old growth, or ancient (meaning, that unlike old growth that might have a catastrophic fire reset the majority of the system every 350-500 years, an ancient forest-usually as smaller groves within an old growth system- is so wet that even a lightning strike fire in the heart of summer is unlikely to burn more than that one tree, or perhaps it's closest neighbor, and these forests are dominated by extremely old trees 500-2000+) at the time of the clearcut. I've seen time and again that the pattern of the rings are not uniform, that they vary significantly from year to year in some areas but can have some uniform patterns over the span of decades, and I have been led to believe that this is as a result of what the tree experienced in any given year. Sometimes there is uniformity in it's pattern, which is a result of steady growth (this is more likely in an even aged stand following a catastrophic event, but happens in all types of forest and correlates with a period (years, decades... ) of steady relatively even growth), but generally there will be some variations in the width of the rings due to multi aged effect of healthy old growth systems, and the effect of one tree on the next in addition to the correlations between climatic and external influences, such as drought, el nina type extreme wetness, damaging scars from impacts, fires, et cetera. This is not simply to do with second growth forests, but is true (to my knowledge) across the board (pun intended). I've seen way too many huge old growth sawn stumps to consider your initial statement about growth rings as valid. These include, hemlock, balsam fir, Douglas Fir, Red Cedar, Sitka Spruce, Lodgepole pine, and many of these have diameters that a person can lay down on. I do not have any experience with Redwoods, or their related forests, except to walk in a few of older stands in California and Oregon. I'm glad to hear that they are tipping the balance in the direction of regeneration.
However, Robert, while of course your points about tree growth rates are useful in selective logging of second growth to maximize regrowth,